---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 08/22/06: 50 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:17 AM - Re: AeroElectric-List Digest: 17 Msgs - 08/18/06 (Ernest Christley) 2. 02:53 AM - Re: Pullable 80A Circuit Breaker (Kevin Horton) 3. 03:10 AM - Re: Super flag (William Gill) 4. 03:42 AM - Re: RPM drop Problem (FLYaDIVE@aol.com) 5. 06:07 AM - Re: MOV's vs. Diodes for spike suppression (Robert L. Nuckolls, III) 6. 06:07 AM - Re: MOV's vs. Diodes for spike suppression (Robert L. Nuckolls, III) 7. 06:18 AM - Flap switches/relay wiring (wgill10@comcast.net) 8. 06:46 AM - Re: Re: AeroElectric-List Digest: 17 Msgs - 08/18/06 (Harley) 9. 06:57 AM - Re: Flap switches/relay wiring (Robert L. Nuckolls, III) 10. 07:02 AM - Re: Flap switches/relay wiring (FLYaDIVE@aol.com) 11. 07:05 AM - Re: MOV's (Ernest Christley) 12. 07:08 AM - Re: Pullable 80A Circuit Breaker (glen matejcek) 13. 07:16 AM - Re: Flap switches/relay wiring (Bruce Gray) 14. 07:19 AM - Re: Flap switches/relay wiring (Lloyd, Daniel R.) 15. 07:24 AM - Re: Flap switches/relay wiring (Robert L. Nuckolls, III) 16. 07:54 AM - Re: Flap switches/relay wiring (wgill10@comcast.net) 17. 08:01 AM - Re: Re: Pullable 80A Circuit Breaker (Denis Walsh) 18. 08:03 AM - Re: Flap switches/relay wiring (Dwight Frye) 19. 08:34 AM - Re: Flap switches/relay wiring (Bruce Gray) 20. 08:38 AM - Re: Re: Pullable 80A Circuit Breaker (Robert L. Nuckolls, III) 21. 08:58 AM - Re: Re: Pullable 80A Circuit Breaker (Hopperdhh@aol.com) 22. 09:06 AM - Re: Re: Pullable 80A Circuit Breaker (Hopperdhh@aol.com) 23. 09:16 AM - Re: Re: Pullable 80A Circuit Breaker (Matt Prather) 24. 09:47 AM - Re: Flap switches/relay wiring (Dwight Frye) 25. 09:47 AM - Re: Re: MOV's (Paul Messinger) 26. 10:49 AM - Re: MOV's (Eric M. Jones) 27. 10:54 AM - Re: Re: MOV's (Dave N6030X) 28. 11:11 AM - Re: Flap switches/relay wiring (FLYaDIVE@aol.com) 29. 11:20 AM - Re: Flap switches/relay wiring (FLYaDIVE@aol.com) 30. 01:32 PM - Re: Re: MOV's (Paul Messinger) 31. 01:53 PM - Re: Re: MOV's (Ken) 32. 01:58 PM - Re: Re: MOV's (Tony Babb) 33. 02:10 PM - Re: Flap switches/relay wiring (Gilles Thesee) 34. 02:35 PM - Ergonomics (was: Flap switches/relay wiring) (Brian Lloyd) 35. 03:40 PM - Re: Ergonomics (was: Flap switches/relay wiring) () 36. 03:40 PM - Re: Ergonomics (was: Flap switches/relay wiring) () 37. 03:44 PM - Re: Flap switches/relay wiring (FLYaDIVE@aol.com) 38. 04:15 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 39. 06:42 PM - Re: Ergonomics (was: Flap switches/relay wiring) (Peter Pengilly) 40. 07:29 PM - Re: Ergonomics (was: Flap switches/relay wiring) (Rob Wright) 41. 07:34 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 42. 08:12 PM - Re: Ergonomics (was: Flap switches/relay wiring) (Bruce Gray) 43. 08:24 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 44. 08:49 PM - Re: Re: MOV's (Paul Messinger) 45. 08:49 PM - Re: Re: MOV's (Paul Messinger) 46. 08:57 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 47. 09:42 PM - Re: Re: MOV's/ opening arc (Paul Messinger) 48. 11:00 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 49. 11:21 PM - Re: Re: MOV's (Robert L. Nuckolls, III) 50. 11:47 PM - B-lead Contactors (was MOV's) (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 12:17:37 AM PST US From: Ernest Christley Subject: AeroElectric-List: Re: AeroElectric-List Digest: 17 Msgs - 08/18/06 --> AeroElectric-List message posted by: Ernest Christley AeroElectric-List Digest Server wrote: >Scott Lewis wrote: > > >>Fergus Kyle wrote: >> >> >>>It also implies the PUBLIC is stupid and easily swayed. If that is >>>true his boss is a perfect example. Perhaps that is what marketting >>>is - consumption by the stupid? >>> >>> >>And right there you have hit the nail on the head!! >> >>Also, politics is the art of appealing to the fears of the stupid. >> >> > >I agree but I would change the word "stupid" to "ignorant". I don't >believe there are hundreds of millions of stupid people around the world >voting against their own interests, they are simply ignorant of what's >happening around them. > > > Never forget that, by definition, 50% of people have below average intelligence. I had an argument with one of my wife's girlfriends once over the cheap generics versus expensive but heavily advertised aspirin. I explained the long history of aceti-salicyllic acid (sp?). I showed her how the FDA requires manufacturers to divulge the quantity of each active ingredient right on the packaging. She countered that "they put other stuff in that isn't active but makes it work better." I quit arguing. Advertisers won. In a different instance, another friend was amazed that all of our dinner plates didn't match. How often do you see mismatched dishes on a television show that doesn't involve foul-mouthed trailer trash? I don't know how it is in other countries, but over the last 50yrs Americans have been slowly converted from citizens to "consumers". This has been done with a constant barrage of television and radio advertising that can create feelings and emotions without having to be filtered by the cognitive process of reading and digesting the written word. "Don't think. That's hard. Just have fun. Buy {new shiny thing}. {slightly used shiny thing} is outdated and no longer fashionable. You will only be young, beautiful and hip if you have {new shiny thing}. If one dish breaks, you have to throw out the whole set and buy another. Store brand apirin won't work. You need 5 different flavors depending on which quadrant of your head the ache is in." Cognizant citizens make poor consumers. It's not smart vs stupid. It's trained vs untrained. Spend an hour in front of a TV with a typical teenager. Find out what they think about the advertisements. Everything is cool and exciting. Find a way to isolate them from the boob-tube for a week or two, and then spend another hour at it with them. You'll be amazed at the number of times 'stupid' in used in reference to the commercials. Until we can turn off all the raio an television stations for a few weeks (which will cut consumerism and put most of us out of our jobs), we will have to deal with the prevalent conditions. No matter how it sticks in my craw, I know that I must convince ignoramuses that my airplane is safe. (Not 'safer than a Cessna'. They think those are all kamakazi dive bombers.) We must convince them we're safe. Experimental and amatuer have to be either qualified or not used. "Experimental? Not really. This design has been flying for well over 40 years." "All 'amatuer' means is that I don't have to make a profit. Instead, I have to keep rebuilding a part till it is right. I don't have a schedule for that reason. It will fly only after everything is perfect." If we can fit those explanations into ABEA, then I'm all for it; otherwise, let's stick with OBAM for the time being. -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 2 _____________________________________ Time: 02:53:59 AM PST US From: Kevin Horton Subject: Re: AeroElectric-List: Pullable 80A Circuit Breaker On 22 Aug 2006, at 24:37, Speedy11@aol.com wrote: > Does anybody know a source for a pullable 80A CB to use for the > alternator? I've checked several sources and have found 80A CBs > that cannot be pulled - they can only be reset, but none that are > pullable. > I bought one at Sun n Fun only to discover later that it is 28v. I would have thought that the rating meant the maximum voltage that the CB could be used with. Any lower voltage should be OK. It is measuring amperage, not voltage, and 80A is 80A, no matter what the system voltage is. Kevin Horton Ottawa, Canada ________________________________ Message 3 _____________________________________ Time: 03:10:09 AM PST US From: "William Gill" Subject: RE: AeroElectric-List: Super flag --> AeroElectric-List message posted by: "William Gill" Is this in regards to a bendix-king nav indicator and the wire connection to the nav super flag? Tell us what model indicator and the specific question you have. Bill -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John F. Herminghaus Sent: Tuesday, August 22, 2006 12:24 AM Subject: AeroElectric-List: Super flag --> AeroElectric-List message posted by: "John F. Herminghaus" What is a super flag? Is there any source where it is described in detail? John Herminghaus ________________________________ Message 4 _____________________________________ Time: 03:42:52 AM PST US From: FLYaDIVE@aol.com Subject: Re: AeroElectric-List: RPM drop Problem --> AeroElectric-List message posted by: FLYaDIVE@aol.com Dennis: Here are a few things I would check: ~ Timing ~ Fuel - Have you been using AvGas? If so you may have some coking around the exhaust valve(s). ~ Spark Plug - Bad plug, carbon or lead fouling, cracked porcelain (swap left and right plugs. If the problem follows the plugs, then just search down the bad plug.) ~ Harness - Check the length of the coil springs. Give them a slight pull to stretch the length. Also check down into the plugs looking for carbon or arcing. (I'm assuming you are using massive plugs?) Plugs - While looking down, make sure the screw down there is tight. Mags - You said you eliminated them as being the problem, but why and how? Have you looked inside? What is the e-gap and condition of the coil? Does the problem get worse with time and heat? OK, that is all I can think about before I have my coffee. Let us know how you make out. Barry (McCoy) "Chop'd Liver" "Show them the first time, correct them the second time, kick them the third time." Yamashiada ============================================ I have a 1946 Ercoupe with a 85 HP (started out as a 75HP) Continental engine with a 200 RPM drop on the right mag at run-up. Mechanics have 100% eliminated as the problem both mags, all plugs, P-leads, and switch system. Also, the engine ran perfectly for the last 25 hours after a new wiring harness was installed. The harness was checked out and all wires were fine. We do not know what to check next. I would appreciate any advice anyone can give us. Thanks. Dennis Hatfield ________________________________ Message 5 _____________________________________ Time: 06:07:59 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: MOV's vs. Diodes for spike suppression --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:02 AM 8/21/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >Coil Suppression: > >MOVs are considered to be better than diodes, although they have higher >impedance. But MOVs typically have a limited lifetime. The lifetime issue controls when the MOV is stressed repeatedly to its maximum rated energy levels . . . in coil spike suppression, the energies are tiny by comparison and life-limits do not become an issue. >Diodes are not the best method today. Not even the second-, third-, or >fourth- best method. But in the 1960's they were the way to go. Measurements on my bench have failed to demonstrate the suggestion. A number of papers have been cited over the years, some written by some folks who work for big name companies like Tyco-Amp, Teledyne, etc. wherein authors have suggested that the readily observable effects of plain diodes on opening delay (no big deal in 99.99% of applications) directly translates to slower contact spreading velocity (extended arcing during contact break). Two separate conditions are in play. (1) slower rate of decay in the relay or contactor's coil current and (2) rate of decay in the magnetic attraction force as the moveable armature begins to separate from its seated position within the device. The diode has a profound effect on (1) but a small effect on (2). Most of the papers I've read accurately observed and discussed (1) and even did some measurements but then went on to improperly assume that similar effects would be noted for (2) as well. The trace at: http://www.aeroelectric.com/Pictures/Curves/704-1DelayNoDiode.gif Shows contact OPENING DELAY of an S704-1 plastic high current relay when no diode was present across the coil and the coil current was being interrupted by the "perfect switch". Note the expected coil spike on channel 2 and the opening delay of about 2.5 mS. You can see the arcing across spreading contacts if you look carefully at the falling trace on channel 1. http://www.aeroelectric.com/Pictures/Curves/704-1DelayWithDiode.gif This trace shows what happens when we use the plain-vanilla diode across the coil. Yes, OPENING DELAY goes up by a factor of 500% to about 12.5 mS. Now, let's go take a close look at the arcing phenomenon noted in the two traces above . . . http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif . . . with no diode, a series of about 10 measurements produced an opening time (ARC DURATION) that averaged 210 uS. In the next trace . . . http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeWithDiode.gif . . . the diode was put back on and we see an average of 230 uS ARC DURATION for an increase of about 10% I did similar experiments with other relays and did not formalize the data gathering but got similar results. Bottom line is that the use of the lowly diode for coil spike suppression does not deserve relegation to the dust bins of electronic history as a 5th-rate spike suppression technique. Unfortunately, some big names working for big companies have stubbed their toes on significant but error driven assumptions. The repeatable experiment has demonstrated otherwise. Continued use of diodes as suggested in the 'Connection and on many drawings posted to the website is not a recipe for failure. Substitution of a more "modern" technique will produce no observable effect on the service life of your relays and contactors. Bob . . . ________________________________ Message 6 _____________________________________ Time: 06:07:59 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: MOV's vs. Diodes for spike suppression --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:02 AM 8/21/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >Coil Suppression: > >MOVs are considered to be better than diodes, although they have higher >impedance. But MOVs typically have a limited lifetime. The lifetime issue controls when the MOV is stressed repeatedly to its maximum rated energy levels . . . in coil spike suppression, the energies are tiny by comparison and life-limits do not become an issue. >Diodes are not the best method today. Not even the second-, third-, or >fourth- best method. But in the 1960's they were the way to go. Measurements on my bench have failed to demonstrate the suggestion. A number of papers have been cited over the years, some written by some folks who work for big name companies like Tyco-Amp, Teledyne, etc. wherein authors have suggested that the readily observable effects of plain diodes on opening delay (no big deal in 99.99% of applications) directly translates to slower contact spreading velocity (extended arcing during contact break). Two separate conditions are in play. (1) slower rate of decay in the relay or contactor's coil current and (2) rate of decay in the magnetic attraction force as the moveable armature begins to separate from its seated position within the device. The diode has a profound effect on (1) but a small effect on (2). Most of the papers I've read accurately observed and discussed (1) and even did some measurements but then went on to improperly assume that similar effects would be noted for (2) as well. The trace at: http://www.aeroelectric.com/Pictures/Curves/704-1DelayNoDiode.gif Shows contact OPENING DELAY of an S704-1 plastic high current relay when no diode was present across the coil and the coil current was being interrupted by the "perfect switch". Note the expected coil spike on channel 2 and the opening delay of about 2.5 mS. You can see the arcing across spreading contacts if you look carefully at the falling trace on channel 1. http://www.aeroelectric.com/Pictures/Curves/704-1DelayWithDiode.gif This trace shows what happens when we use the plain-vanilla diode across the coil. Yes, OPENING DELAY goes up by a factor of 500% to about 12.5 mS. Now, let's go take a close look at the arcing phenomenon noted in the two traces above . . . http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif . . . with no diode, a series of about 10 measurements produced an opening time (ARC DURATION) that averaged 210 uS. In the next trace . . . http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeWithDiode.gif . . . the diode was put back on and we see an average of 230 uS ARC DURATION for an increase of about 10% I did similar experiments with other relays and did not formalize the data gathering but got similar results. Bottom line is that the use of the lowly diode for coil spike suppression does not deserve relegation to the dust bins of electronic history as a 5th-rate spike suppression technique. Unfortunately, some big names working for big companies have stubbed their toes on significant but error driven assumptions. The repeatable experiment has demonstrated otherwise. Continued use of diodes as suggested in the 'Connection and on many drawings posted to the website is not a recipe for failure. Substitution of a more "modern" technique will produce no observable effect on the service life of your relays and contactors. Bob . . . ________________________________ Message 7 _____________________________________ Time: 06:18:10 AM PST US From: wgill10@comcast.net Subject: AeroElectric-List: Flap switches/relay wiring Im planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Vans supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance. Bill Gill RV-7 wiring Lees Summit, MO

Im planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Vans supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance.

 

Bill Gill

RV-7 wiring

Lees Summit, MO
________________________________ Message 8 _____________________________________ Time: 06:46:34 AM PST US From: Harley Subject: Re: AeroElectric-List: Re: AeroElectric-List Digest: 17 Msgs - 08/18/06 ________________________________ Message 9 _____________________________________ Time: 06:57:15 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:17 PM 8/22/2006 +0000, you wrote: >I'm planning to install a switch for the flaps in the pilot stick grip in >addition to the standard panel mounted switch that Van's supplies. Can I >simply hook both switches to the same relay(s)? Any suggestions regarding >relay (P/N & source). Thanks in advance for your assistance You can do this. Wiring is similar to that shown in . . http://www.aeroelectric.com/PPS/Flight/Trim/Trim5.pdf where two switches are used to drive a single set of direction control relays for pitch trim . . . same thing works for flaps. Relay can be like the 137357PS in lower left corner of page at: http://www.jameco.com/Jameco/catalogs/c263/P202.pdf This is similar to the B&C S704-1 illustrated in many of my drawings. Now, have you considered design philosophy? Flaps like trim are motor driven surfaces that can have a profound effect on flight dynamics and in some cases, stresses that approach structural limits. Increased complexity of the flap controls that adds the relatively un-robust and easy-to-hit stick grip switches would not pass muster with the customers, managers and regulators I work for. Flaps are used very sparingly during a flight. Uncontrolled operation of flaps under certain conditions are a recipe for a very bad day. I'll suggest that the simplest wiring with the most robust components will minimize probability of an unhappy event. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 10 ____________________________________ Time: 07:02:36 AM PST US From: FLYaDIVE@aol.com Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: FLYaDIVE@aol.com In a message dated 8/22/06 9:21:00 AM Eastern Daylight Time, wgill10@comcast.net writes: > Im planning to install a switch for the flaps in the pilot stick grip in > addition to the standard panel mounted switch that Vans supplies. Can I > simply hook both switches to the same relay(s)? Any suggestions regarding > relay (P/N & source). Thanks in advance for your assistance. > > Bill Gill > RV-7 wiring > Lees Summit, MO ================= Bill: Go for it. Just set the switch up in parallel. BUT! Only ONE switch can be used at a time. Barry "Chop'd Liver" "Show them the first time, correct them the second time, kick them the third time." Yamashiada ________________________________ Message 11 ____________________________________ Time: 07:05:37 AM PST US From: Ernest Christley Subject: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: Ernest Christley >--> AeroElectric-List message posted by: "Eric M. Jones" > >Coil Suppression: > >Diodes are not the best method today. Not even the second-, third-, or fourth- >best method. But in the 1960's they were the way to go. > > > In what aspect does the common, sub-$1, available-everywhere diode fall short enough to justify paying $30 for your single-source solution? -- ,|"|"|, Ernest Christley | ----===<{{(oQo)}}>===---- Dyke Delta Builder | o| d |o http://ernest.isa-geek.org | ________________________________ Message 12 ____________________________________ Time: 07:08:15 AM PST US From: "glen matejcek" Subject: AeroElectric-List: RE: Pullable 80A Circuit Breaker --> AeroElectric-List message posted by: "glen matejcek" Hi Stan- >I bought one at Sun n Fun only to discover later that it is 28v. 28V is the maximum system voltage for that CB. The CB you bought should be fine for your 14V installation. glen matejcek aerobubba@earthlink.net ________________________________ Message 13 ____________________________________ Time: 07:16:48 AM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: Flap switches/relay wiring Have you considered what would happen if you or your passenger inadvertently activated the flap switch while as cruse speed? Normally, it's not a good idea to put switches on control sticks that if activated at the wrong time could adversely impact the safety of the aircraft. Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net Sent: Tuesday, August 22, 2006 9:17 AM Subject: AeroElectric-List: Flap switches/relay wiring I'm planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Van's supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance. Bill Gill RV-7 wiring Lee's Summit, MO ________________________________ Message 14 ____________________________________ Time: 07:19:02 AM PST US Subject: RE: AeroElectric-List: Flap switches/relay wiring From: "Lloyd, Daniel R." www.aircraftextras.com has both the relay boards and the air speed switch to cut out the flaps at certain speeds, which is recommended if you are putting flaps on the sticks because of accidental high speed deployment by bumping the stick. Dan 40269 RV10E (N289DT) _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net Sent: Tuesday, August 22, 2006 9:17 AM Subject: AeroElectric-List: Flap switches/relay wiring I'm planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Van's supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance. Bill Gill RV-7 wiring Lee's Summit, MO ________________________________ Message 15 ____________________________________ Time: 07:24:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:01 AM 8/22/2006 -0400, you wrote: >--> AeroElectric-List message posted by: FLYaDIVE@aol.com > >In a message dated 8/22/06 9:21:00 AM Eastern Daylight Time, >wgill10@comcast.net writes: > > > Im planning to install a switch for the flaps in the pilot stick > grip in > > addition to the standard panel mounted switch that Vans supplies. Can I > > simply hook both switches to the same relay(s)? Any suggestions regarding > > relay (P/N & source). Thanks in advance for your assistance. > > > > Bill Gill > > RV-7 wiring > > Lees Summit, MO >================= >Bill: > >Go for it. Just set the switch up in parallel. BUT! Only ONE switch can be >used at a time. Actually, if wired per my earlier suggestions, operating both switches at the same to extend/retract flaps will cause the flaps to continue motion until BOTH switches are released. If both switches are operated in opposite directions, the motion simply stops until one switch is released whereupon motion will happen in response to the switch that is still closed. No damage will happen due to conflicting commands. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 16 ____________________________________ Time: 07:54:46 AM PST US From: wgill10@comcast.net Subject: RE: AeroElectric-List: Flap switches/relay wiring Hello Bruce, The flap switch would only be installed on the pilot's stick grip -- not co-pilot side. Also, the switch will be momentary and mounted on top of the stick making inadvertent activation difficult. Bill -------------- Original message -------------- From: "Bruce Gray" Have you considered what would happen if you or your passenger inadvertently activated the flap switch while as cruse speed? Normally, it's not a good idea to put switches on control sticks that if activated at the wrong time could adversely impact the safety of the aircraft. Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net Sent: Tuesday, August 22, 2006 9:17 AM Subject: AeroElectric-List: Flap switches/relay wiring Im planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Vans supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance. Bill Gill RV-7 wiring Lees Summit, MO matronics.com/Navigator?AeroElectric-List
Hello Bruce,
 
The flap switch would only be installed on the pilot's stick grip -- not co-pilot side. Also, the switch will be momentary and mounted on top of the stick making inadvertent activation difficult.
 
Bill
 
-------------- Original message --------------
From: "Bruce Gray" <Bruce@glasair.org>
Have you considered what would happen if you or your passenger inadvertently activated the flap switch while as cruse speed? Normally, it's not a good idea to put switches on control sticks that if activated at the wrong time could adversely impact the safety of the aircraft.
 
 

Bruce
www.glasair.org
 

 
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net
Sent: Tuesday, August 22, 2006 9:17 AM
To: aeroelectric-list@matronics.com
Subject: AeroElectric-List: Flap switches/relay wiring

Im planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Vans supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance.

 

Bill Gill

RV-7 wiring

Lees Summit, MO



matronics.com/Navigator?AeroElectric-List
________________________________ Message 17 ____________________________________ Time: 08:01:01 AM PST US From: Denis Walsh Subject: Re: AeroElectric-List: RE: Pullable 80A Circuit Breaker --> AeroElectric-List message posted by: Denis Walsh While I am waiting for the real experts to weigh in, I offer the following unsubstantiated feeling: I don't think a cb "senses" either volts or amps. Rather it reacts to heat, whose generation is better measured in watts which is a function of both. I would therefore surmise that the cb in question would be well within its rated range; however would probably not trip a 14 volt load until 160 amps. well, where are the electro-experts now that we need them?? Denis Walsh On Aug 22, 2006, at 07:06 292080008, glen matejcek wrote: > --> AeroElectric-List message posted by: "glen matejcek" > > > > Hi Stan- > >> I bought one at Sun n Fun only to discover later that it is 28v. > > 28V is the maximum system voltage for that CB. The CB you bought > should be > fine for your 14V installation. > > glen matejcek > aerobubba@earthlink.net > > ________________________________ Message 18 ____________________________________ Time: 08:03:06 AM PST US From: Dwight Frye Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: Dwight Frye On Tue Aug 22 09:56:28 2006, Robert L. Nuckolls, III wrote : >[ ... snip ... ] > Increased complexity of the flap controls that adds > the relatively un-robust and easy-to-hit stick grip > switches would not pass muster with the customers, > managers and regulators I work for. > > Flaps are used very sparingly during a flight. Uncontrolled > operation of flaps under certain conditions are a > recipe for a very bad day. I'll suggest that the > simplest wiring with the most robust components > will minimize probability of an unhappy event. For what its worth ...... I have a friend with an RV-7 who has a flap switch on his stick grip. It is on top, and he has _twice_ hit it while fiddling with charts/etc. in cruise. In both cases he caught it before there was a big problem ..... but he was NOT happy that it happened in either case. His conclusion is that the design is not a good one, for him at least. The flap-switch-on-the-stick idea sounded great to me until I heard my friend's story. I have decided that for me the flap switch is going on the panel within a convenient distance from the throttle. Still easy to get to in the pattern (my hand should be near the throttle most the time then anyway) and less likely to be hit accidentally. YMMV. -- Dwight ________________________________ Message 19 ____________________________________ Time: 08:34:05 AM PST US From: "Bruce Gray" Subject: RE: AeroElectric-List: Flap switches/relay wiring Well, whatever floats your boat. Good Luck! And be careful. Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net Sent: Tuesday, August 22, 2006 10:54 AM Subject: RE: AeroElectric-List: Flap switches/relay wiring Hello Bruce, The flap switch would only be installed on the pilot's stick grip -- not co-pilot side. Also, the switch will be momentary and mounted on top of the stick making inadvertent activation difficult. Bill -------------- Original message -------------- From: "Bruce Gray" Have you considered what would happen if you or your passenger inadvertently activated the flap switch while as cruse speed? Normally, it's not a good idea to put switches on control sticks that if activated at the wrong time could adversely impact the safety of the aircraft. Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of wgill10@comcast.net Sent: Tuesday, August 22, 2006 9:17 AM Subject: AeroElectric-List: Flap switches/relay wiring I'm planning to install a switch for the flaps in the pilot stick grip in addition to the standard panel mounted switch that Van's supplies. Can I simply hook both switches to the same relay(s)? Any suggestions regarding relay (P/N & source). Thanks in advance for your assistance. Bill Gill RV-7 wiring Lee's Summit, MO matronics.com/Navigator?AeroElectric-List ________________________________ Message 20 ____________________________________ Time: 08:38:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Pullable 80A Circuit Breaker --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:06 AM 8/22/2006 -0400, you wrote: >--> AeroElectric-List message posted by: "glen matejcek" > > > > Hi Stan- > > >I bought one at Sun n Fun only to discover later that it is 28v. > >28V is the maximum system voltage for that CB. The CB you bought should be >fine for your 14V installation. Glen is correct. I'll amplify his words with the notion that voltage ratings on switches and breakers are MAXIMUM level for operating voltage at the cited current level. There is no practical minimum voltage. See: http://aeroelectric.com/articles/swtchrat.pdf While this article speaks specifically to switches, the same ratings philosophies apply to breakers that are simply automated switches designed to sense current. Bob . . . ________________________________ Message 21 ____________________________________ Time: 08:58:39 AM PST US From: Hopperdhh@aol.com Subject: Re: AeroElectric-List: RE: Pullable 80A Circuit Breaker Glen, CB's are rated in volts only to show what kind of circuit they should be used in. In other words don't use a breaker rated for 28 volts in a 120 volt circuit. A 28 volt breaker would IMHO be fine for use in a 12-14 volt circuit. It is in series with the load, so it can only know the current. It has no way of knowing the voltage or therefore the wattage of the load. It is heat activated by having a small amount of resistance, and the heating power is I*I*R. (I is current, and R is resistance.) This causes it to waste a little power (and voltage) in order to do its job. Dan Hopper RV-7A Playing with electricity since age 2 when I plugged a key into a wall outlet. Nothing happened so I plugged in another key. I'm told it sent me across the room. I've been hooked on the stuff ever since! In a message dated 8/22/2006 11:03:30 A.M. Eastern Daylight Time, denis.walsh@comcast.net writes: --> AeroElectric-List message posted by: Denis Walsh While I am waiting for the real experts to weigh in, I offer the following unsubstantiated feeling: I don't think a cb "senses" either volts or amps. Rather it reacts to heat, whose generation is better measured in watts which is a function of both. I would therefore surmise that the cb in question would be well within its rated range; however would probably not trip a 14 volt load until 160 amps. well, where are the electro-experts now that we need them?? Denis Walsh On Aug 22, 2006, at 07:06 292080008, glen matejcek wrote: > --> AeroElectric-List message posted by: "glen matejcek" > > > > Hi Stan- > >> I bought one at Sun n Fun only to discover later that it is 28v. > > 28V is the maximum system voltage for that CB. The CB you bought > should be > fine for your 14V installation. > > glen matejcek > aerobubba@earthlink.net > > ________________________________ Message 22 ____________________________________ Time: 09:06:10 AM PST US From: Hopperdhh@aol.com Subject: Re: AeroElectric-List: RE: Pullable 80A Circuit Breaker Glen, Sorry, I should have said Stan at the top. I agree with you completely. Bob's post came in after I hit send, so I think we are all in agreement. Dan In a message dated 8/22/2006 12:02:38 P.M. Eastern Daylight Time, Hopperdhh@aol.com writes: Glen, CB's are rated in volts only to show what kind of circuit they should be used in. In other words don't use a breaker rated for 28 volts in a 120 volt circuit. A 28 volt breaker would IMHO be fine for use in a 12-14 volt circuit. It is in series with the load, so it can only know the current. It has no way of knowing the voltage or therefore the wattage of the load. It is heat activated by having a small amount of resistance, and the heating power is I*I*R. (I is current, and R is resistance.) This causes it to waste a little power (and voltage) in order to do its job. Dan Hopper RV-7A Playing with electricity since age 2 when I plugged a key into a wall outlet. Nothing happened so I plugged in another key. I'm told it sent me across the room. I've been hooked on the stuff ever since! In a message dated 8/22/2006 11:03:30 A.M. Eastern Daylight Time, denis.walsh@comcast.net writes: --> AeroElectric-List message posted by: Denis Walsh While I am waiting for the real experts to weigh in, I offer the following unsubstantiated feeling: I don't think a cb "senses" either volts or amps. Rather it reacts to heat, whose generation is better measured in watts which is a function of both. I would therefore surmise that the cb in question would be well within its rated range; however would probably not trip a 14 volt load until 160 amps. well, where are the electro-experts now that we need them?? Denis Walsh On Aug 22, 2006, at 07:06 292080008, glen matejcek wrote: > --> AeroElectric-List message posted by: "glen matejcek" > > > > Hi Stan- > >> I bought one at Sun n Fun only to discover later that it is 28v. > > 28V is the maximum system voltage for that CB. The CB you bought > should be > fine for your 14V installation. > > glen matejcek > aerobubba@earthlink.net > > bsp; --> nbsp; - NEW MATRONICS LIST WIKI - ======================== (http://www.matronics.com/Navigator?AeroElectric-List) (http://www.matronics.com/contribution) ________________________________ Message 23 ____________________________________ Time: 09:16:52 AM PST US Subject: Re: AeroElectric-List: RE: Pullable 80A Circuit Breaker From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Err.. I am not an expert, but I don't think that is completely correct. Heat generated is correct, but the heat is generated solely by the current passing through the CB. The system voltage has no bearing on how much heat is generated. Draw the circuit and you can see why. The CB goes in series with the load. Beit a 2V or 200V system, a particular current through the CB causes a corresponding voltage drop across the CB while the CB is closed. The voltage rating is more related to the ability of the CB to open an operating (overloaded) circuit. The higher the system voltage the harder it is to open the circuit (break the current) for a given current. Voltage rating is likely about contact speed and distance (maybe not both). A larger system voltage implies the need for faster contacts and/or larger contact distance. Regards, Matt- > --> AeroElectric-List message posted by: Denis Walsh > > > While I am waiting for the real experts to weigh in, I offer the > following unsubstantiated feeling: > > I don't think a cb "senses" either volts or amps. Rather it reacts > to heat, whose generation is better measured in watts which is a > function of both. > > I would therefore surmise that the cb in question would be well > within its rated range; however would probably not trip a 14 volt > load until 160 amps. > > well, where are the electro-experts now that we need them?? > Denis Walsh > > On Aug 22, 2006, at 07:06 292080008, glen matejcek wrote: > >> --> AeroElectric-List message posted by: "glen matejcek" >> >> >> >> Hi Stan- >> >>> I bought one at Sun n Fun only to discover later that it is 28v. >> >> 28V is the maximum system voltage for that CB. The CB you bought >> should be >> fine for your 14V installation. >> >> glen matejcek >> aerobubba@earthlink.net >> >> >> >> >> >> > > ________________________________ Message 24 ____________________________________ Time: 09:47:16 AM PST US From: Dwight Frye Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: Dwight Frye On Tue Aug 22 10:53:49 2006, wgill10@comcast.net wrote : >--> AeroElectric-List message posted by: wgill10@comcast.net >Hello Bruce, > >The flap switch would only be installed on the pilot's stick grip -- not >co-pilot side. Also, the switch will be momentary and mounted on top of >the stick making inadvertent activation difficult. One followup note ... while I (strongly!) agree that having the flap switch on the co-pilot's stick would be bad news, I disagree with the statement that putting it on top of the stick would make inadvertant activation difficult. My friend has his flap switch on the top of the stick in his RV-7, and (as I said before) has accidentally deployed flaps (BRIEFLY, and only minimally, before he caught the mistake) at cruise speeds. This was due to messing with chart books while flying and having them bump the little momentary switch on top of the stick. Consider my comments only as food for thought and a story that speaks to the specific issue under debate. In the end you should clearly just do what you feel would work for you. -- Dwight ________________________________ Message 25 ____________________________________ Time: 09:47:16 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Paul Messinger" I get them for as little as under 25 cents each in qty of one (15 cents each for 100). All industrial electronic suppliers stock them in many types and brands. $30 will get you 100 parts including shipping in some cases. The cost difference is not significant in the big picture. Eric provides a value added KIT of parts etc its up to you to convert convenience for absolute cost. (Eric also posted the exact part number for those who wanted to get just the diodes from most any source as above) Relays with internal diodes are available simply because of demand, not for technical reasons. Engineers resist change and if it seems to work why change? Transorbs are better or (no worse in some opinions) and work in 100% of the cases. Its a "no brainier" for some of us. While they may not appear to make a difference in a 5 amp resistive load with a small relay, Transorbs are proven to have a large advantage in inductive and larger current loads with larger or different type relays. But so what! Bob has his "repeatable" test of one and is convinced he is right. One size (test) does not fit all cases and perhaps its 90% (for diodes) for the average aircraft but clearly not 99.99% based on MY own lab repeatable tests. The entire world, North America, and Europe for example, ALL say the same thing that Eric referenced about Diodes vs. Transorbs etc. Just who is out of step here???? There are hundreds in every modern auto. Given the number of autos made each year and yes Transorbs do cost more than simple diodes why would auto makers spend millions of $$ every year for them if the diode was as good and they could save all that money with diodes. Perhaps they know something not stated on this list?? If you look at the available data including the many references and read and understand the available info, its far more compelling than appears on the surface. Is "good enough" OK if you can get better for little more? I am unwilling to have another useless debate. It ends up with a lot of words/heat etc. and no opinion ever gets changed. Paul ----- Original Message ----- From: "Ernest Christley" Sent: Tuesday, August 22, 2006 7:02 AM Subject: AeroElectric-List: Re: MOV's > --> AeroElectric-List message posted by: Ernest Christley > > > >>--> AeroElectric-List message posted by: "Eric M. Jones" >> >> >>Coil Suppression: >> >>Diodes are not the best method today. Not even the second-, third-, or >>fourth- >>best method. But in the 1960's they were the way to go. >> >> > In what aspect does the common, sub-$1, available-everywhere diode fall > short enough to justify paying $30 for your single-source solution? > > -- > ,|"|"|, Ernest Christley | > ----===<{{(oQo)}}>===---- Dyke Delta Builder | > o| d |o http://ernest.isa-geek.org | > > ________________________________ Message 26 ____________________________________ Time: 10:49:03 AM PST US Subject: AeroElectric-List: Re: MOV's From: "Eric M. Jones" --> AeroElectric-List message posted by: "Eric M. Jones" > Coil Suppression: > > In what aspect does the common, sub-$1, available-everywhere diode fall > short enough to justify paying $30 for your single-source solution? > -- > ,|"|"|, Ernest Christley Ernest, See both of the links I posted, ref: http://relays.tycoelectronics.com/kilovac/appnotes/transients.asp See: http://www.periheliondesign.com/suppressors/SnapJack.pdf but especially: http://relays.tycoelectronics.com/kilovac/appnotes/fig48.asp You are incorrect on several points-- These are not single sourced. Every manufacturer of bi-directional Zener transient voltage suppressors seems to have a trademarked name for these: Transils, Surmetics, Transorbs, TranZorbs, TransGuards, Mosorbs; the list is endless. We call them SnapJacks. They are 18 Volt 600 Watt axial-lead bi-directional Zener transient voltage suppressors, part number P6KE18CA. The kit includes: (12) P6KE18CA (24") of suitable heat shrink tubing, (4) 1/4" faston solder adaptors (10) 6-8-10 Multistud ring tongue connectors (2) 1/4" ring tongues (2) 5/16" ring tongues (4) Faston tabs rivet or screw mount (1) Instructions and technical details, (1) Perihelion Design catalog (1) Free first-class shipping My accountant says I lost $xx,xxx on my little business in '04 and will maybe break even in '05 and '06, due entirely to my Space Shuttle Switch Guards that I sell to NASA (Perihelion Design parts are in orbit!) and the Military. Selling little SnapJack kits like this is a money loser no matter how you cut it, but I get to hang out with the most interesting people. That's worth a lot. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=56397#56397 ________________________________ Message 27 ____________________________________ Time: 10:54:54 AM PST US From: Dave N6030X Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: Dave N6030X Ok, so translated into complete neophyte-speak, for the rest of "us", this means: " 1. The experts disagree (as they do in high vs low wing) 2. You can use a diode or a transorb, but do use something. 3. Pick whichever you find cheaper and more readily available. 4. A transorb can be wired up either direction, while a diode must be wired with the correct polarity. " Dave Morris N5UP At 11:51 AM 8/22/2006, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >I get them for as little as under 25 cents each in qty of one (15 >cents each for 100). All industrial electronic suppliers stock them >in many types and brands. $30 will get you 100 parts including >shipping in some cases. The cost difference is not significant in >the big picture. > >Eric provides a value added KIT of parts etc its up to you to >convert convenience for absolute cost. (Eric also posted the exact >part number for those who wanted to get just the diodes from most >any source as above) > >Relays with internal diodes are available simply because of demand, >not for technical reasons. Engineers resist change and if it seems >to work why change? > >Transorbs are better or (no worse in some opinions) and work in 100% >of the cases. Its a "no brainier" for some of us. > >While they may not appear to make a difference in a 5 amp resistive >load with a small relay, Transorbs are proven to have a large >advantage in inductive and larger current loads with larger or >different type relays. > >But so what! Bob has his "repeatable" test of one and is convinced >he is right. > >One size (test) does not fit all cases and perhaps its 90% (for >diodes) for the average aircraft but clearly not 99.99% based on MY >own lab repeatable tests. > >The entire world, North America, and Europe for example, ALL say the >same thing that Eric referenced about Diodes vs. Transorbs etc. Just >who is out of step here???? > >There are hundreds in every modern auto. Given the number of autos >made each year and yes Transorbs do cost more than simple diodes why >would auto makers spend millions of $$ every year for them if the >diode was as good and they could save all that money with diodes. >Perhaps they know something not stated on this list?? > >If you look at the available data including the many references and >read and understand the available info, its far more compelling than >appears on the surface. > >Is "good enough" OK if you can get better for little more? > >I am unwilling to have another useless debate. It ends up with a lot >of words/heat etc. and no opinion ever gets changed. > >Paul > > >----- Original Message ----- From: "Ernest Christley" >To: >Sent: Tuesday, August 22, 2006 7:02 AM >Subject: AeroElectric-List: Re: MOV's > > >>--> AeroElectric-List message posted by: Ernest Christley >> >> >> >>>--> AeroElectric-List message posted by: "Eric M. Jones" >>> >>> >>>Coil Suppression: >>> >>>Diodes are not the best method today. Not even the second-, >>>third-, or fourth- >>>best method. But in the 1960's they were the way to go. >>> >>In what aspect does the common, sub-$1, available-everywhere diode >>fall short enough to justify paying $30 for your single-source solution? >> >>-- >> ,|"|"|, Ernest Christley | >>----===<{{(oQo)}}>===---- Dyke Delta Builder | >> o| d |o http://ernest.isa-geek.org | >> > > ________________________________ Message 28 ____________________________________ Time: 11:11:41 AM PST US From: FLYaDIVE@aol.com Subject: Re: AeroElectric-List: Flap switches/relay wiring In a message dated 8/22/2006 10:20:11 AM Eastern Standard Time, Bruce@glasair.org writes: Have you considered what would happen if you or your passenger inadvertently activated the flap switch while as cruse speed? Normally, it's not a good idea to put switches on control sticks that if activated at the wrong time could adversely impact the safety of the aircraft. Bruce www.glasair.org =================================== Yup! A quick Right Cross! This is preceded by the Co-Pilots Check List: 1 - Don't say anything. 2 - Don't touch anything. Barry "Chop'd Liver" "Show them the first time, correct them the second time, kick them the third time." Yamashiada ________________________________ Message 29 ____________________________________ Time: 11:20:33 AM PST US From: FLYaDIVE@aol.com Subject: Re: AeroElectric-List: Flap switches/relay wiring In a message dated 8/22/2006 11:05:53 AM Eastern Standard Time, dwight@openweave.org writes: The flap-switch-on-the-stick idea sounded great to me until I heard my friend's story. I have decided that for me the flap switch is going on the panel within a convenient distance from the throttle. Still easy to get to in the pattern (my hand should be near the throttle most the time then anyway) and less likely to be hit accidentally. YMMV. -- Dwight ================================= Dwight: Hitting the flap switch is just like hitting the Mic switch. It is something you learn ... NOT TO DO. None of us were born knowing how to fly, you just have to make a concuss effort. In all cases. It is like flying: To go DOWN you push down. To go UP you pull up. But what has always confused me is ... If you keep pulling UP you go DOWN? Go figure! Barry "Chop'd Liver" "Show them the first time, correct them the second time, kick them the third time." Yamashiada ________________________________ Message 30 ____________________________________ Time: 01:32:08 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Paul Messinger" Comments by your numbers. 1. I only know one "expert" that disagrees with the use of transorbs. I am sure they are more but the overwhelming majority of my engineering associates agree with the "true experts in the field" of relays and contacts etc. 2. Sort of true in most cases. Not usually true with contactor type relays switching inductive loads for example. There are two issues the coil inductive kick that must be addressed that affects the driver of the coil and the relay contacts which can affect the switched load by delays (seldom) and slow opening which power contactors really have a large delay in many cases and the duration and magnitude of the slow opening of a large inductive load can be damaging. 3. Sure quality and use is trumped by price. 5 cents is better than 25 cents. Using the same logic go to your rat shack and get plastic crimp terminals as they are cheaper and easier to find. 4. Transorbs are both uni-directional and bi-directional. True in one case and polarity is important in the other. However a uni-directional transorb is no better than a diode, and is a diode in that use. Paul ----- Original Message ----- From: "Dave N6030X" Sent: Tuesday, August 22, 2006 10:52 AM Subject: Re: AeroElectric-List: Re: MOV's > --> AeroElectric-List message posted by: Dave N6030X > > > Ok, so translated into complete neophyte-speak, for the rest of "us", this > means: > > " > 1. The experts disagree (as they do in high vs low wing) > 2. You can use a diode or a transorb, but do use something. > 3. Pick whichever you find cheaper and more readily available. > 4. A transorb can be wired up either direction, while a diode must be > wired with the correct polarity. > " > > Dave Morris > N5UP > > At 11:51 AM 8/22/2006, you wrote: >>--> AeroElectric-List message posted by: "Paul Messinger" >> >> >>I get them for as little as under 25 cents each in qty of one (15 cents >>each for 100). All industrial electronic suppliers stock them in many >>types and brands. $30 will get you 100 parts including shipping in some >>cases. The cost difference is not significant in the big picture. >> >>Eric provides a value added KIT of parts etc its up to you to convert >>convenience for absolute cost. (Eric also posted the exact part number for >>those who wanted to get just the diodes from most any source as above) >> >>Relays with internal diodes are available simply because of demand, not >>for technical reasons. Engineers resist change and if it seems to work why >>change? >> >>Transorbs are better or (no worse in some opinions) and work in 100% of >>the cases. Its a "no brainier" for some of us. >> >>While they may not appear to make a difference in a 5 amp resistive load >>with a small relay, Transorbs are proven to have a large advantage in >>inductive and larger current loads with larger or different type relays. >> >>But so what! Bob has his "repeatable" test of one and is convinced he is >>right. >> >>One size (test) does not fit all cases and perhaps its 90% (for diodes) >>for the average aircraft but clearly not 99.99% based on MY own lab >>repeatable tests. >> >>The entire world, North America, and Europe for example, ALL say the same >>thing that Eric referenced about Diodes vs. Transorbs etc. Just who is out >>of step here???? >> >>There are hundreds in every modern auto. Given the number of autos made >>each year and yes Transorbs do cost more than simple diodes why would auto >>makers spend millions of $$ every year for them if the diode was as good >>and they could save all that money with diodes. Perhaps they know >>something not stated on this list?? >> >>If you look at the available data including the many references and read >>and understand the available info, its far more compelling than appears on >>the surface. >> >>Is "good enough" OK if you can get better for little more? >> >>I am unwilling to have another useless debate. It ends up with a lot of >>words/heat etc. and no opinion ever gets changed. >> >>Paul >> >> >>----- Original Message ----- From: "Ernest Christley" >> >>To: >>Sent: Tuesday, August 22, 2006 7:02 AM >>Subject: AeroElectric-List: Re: MOV's >> >> >>>--> AeroElectric-List message posted by: Ernest Christley >>> >>> >>> >>>>--> AeroElectric-List message posted by: "Eric M. Jones" >>>> >>>> >>>>Coil Suppression: >>>> >>>>Diodes are not the best method today. Not even the second-, third-, or >>>>fourth- >>>>best method. But in the 1960's they were the way to go. >>>> >>>In what aspect does the common, sub-$1, available-everywhere diode fall >>>short enough to justify paying $30 for your single-source solution? >>> >>>-- >>> ,|"|"|, Ernest Christley | >>>----===<{{(oQo)}}>===---- Dyke Delta Builder | >>> o| d |o http://ernest.isa-geek.org | >>> >> >> >> >> > > > ________________________________ Message 31 ____________________________________ Time: 01:53:17 PM PST US From: Ken Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: Ken True for a bi-directional transorb. But just to muddy the waters, I kind of like the more common uni-directional transorbs. They will still help with positive spikes (if you believe in positive spikes ;) ). Used across a contactor coil, they may delay the opening a smidge compared to a bidirectional transorb, but I suspect that, like the common diode, they are more effective at preventing negative spikes (if you believe in negative spikes comining off contactor coils ;) ). It seems to me that an 18 volt bidirectional transorb may still let negative spikes through that are large enough to damage electrolytic capacitors and perhaps solid state devices, if there is no battery in the circuit. I guess I used diodes on all the contactors and then added a few transorbs on the b-lead just because I could... Are automobiles incorporating transorbs within some devices now? I've never come across one yet that I've noticed. Ken > 4. A transorb can be wired up either direction, while a diode must be > wired with the correct polarity. > " ________________________________ Message 32 ____________________________________ Time: 01:58:34 PM PST US From: "Tony Babb" Subject: RE: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Tony Babb" Dave, As a neophyte thanks for leading me to the bottom line here - THANK YOU !! Tony -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dave N6030X Sent: Tuesday, August 22, 2006 10:53 AM Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: Dave N6030X --> Ok, so translated into complete neophyte-speak, for the rest of "us", this means: " 1. The experts disagree (as they do in high vs low wing) 2. You can use a diode or a transorb, but do use something. 3. Pick whichever you find cheaper and more readily available. 4. A transorb can be wired up either direction, while a diode must be wired with the correct polarity. " Dave Morris N5UP At 11:51 AM 8/22/2006, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" >--> > >I get them for as little as under 25 cents each in qty of one (15 >cents each for 100). All industrial electronic suppliers stock them >in many types and brands. $30 will get you 100 parts including >shipping in some cases. The cost difference is not significant in >the big picture. > >Eric provides a value added KIT of parts etc its up to you to >convert convenience for absolute cost. (Eric also posted the exact >part number for those who wanted to get just the diodes from most >any source as above) > >Relays with internal diodes are available simply because of demand, >not for technical reasons. Engineers resist change and if it seems >to work why change? > >Transorbs are better or (no worse in some opinions) and work in 100% >of the cases. Its a "no brainier" for some of us. > >While they may not appear to make a difference in a 5 amp resistive >load with a small relay, Transorbs are proven to have a large >advantage in inductive and larger current loads with larger or >different type relays. > >But so what! Bob has his "repeatable" test of one and is convinced >he is right. > >One size (test) does not fit all cases and perhaps its 90% (for >diodes) for the average aircraft but clearly not 99.99% based on MY >own lab repeatable tests. > >The entire world, North America, and Europe for example, ALL say the >same thing that Eric referenced about Diodes vs. Transorbs etc. Just >who is out of step here???? > >There are hundreds in every modern auto. Given the number of autos >made each year and yes Transorbs do cost more than simple diodes why >would auto makers spend millions of $$ every year for them if the >diode was as good and they could save all that money with diodes. >Perhaps they know something not stated on this list?? > >If you look at the available data including the many references and >read and understand the available info, its far more compelling than >appears on the surface. > >Is "good enough" OK if you can get better for little more? > >I am unwilling to have another useless debate. It ends up with a lot >of words/heat etc. and no opinion ever gets changed. > >Paul > > >----- Original Message ----- From: "Ernest Christley" > >To: >Sent: Tuesday, August 22, 2006 7:02 AM >Subject: AeroElectric-List: Re: MOV's > > >>--> AeroElectric-List message posted by: Ernest Christley >> >> >> >>>--> AeroElectric-List message posted by: "Eric M. Jones" >>> >>> >>>Coil Suppression: >>> >>>Diodes are not the best method today. Not even the second-, >>>third-, or fourth- >>>best method. But in the 1960's they were the way to go. >>> >>In what aspect does the common, sub-$1, available-everywhere diode >>fall short enough to justify paying $30 for your single-source solution? >> >>-- >> ,|"|"|, Ernest Christley | >>----===<{{(oQo)}}>===---- Dyke Delta Builder | >> o| d |o http://ernest.isa-geek.org | >> > > ________________________________ Message 33 ____________________________________ Time: 02:10:49 PM PST US From: Gilles Thesee Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: Gilles Thesee Barry and all Some builders I know of even went one step farther : they put the flap switch IN THE PLACE of the trim switch. Thus they ensure consistent inadvertent operation at the worst possible time, as often as possible ;-) One of them even wrote to a flying magazine, to tell how the aircraft was dangerous, since his wife retracted the flaps during take-off ! > > Hitting the flap switch is just like hitting the Mic switch. It is > something you learn ... NOT TO DO. > If you have to learn not to actuate the switch, then it is misplaced. In 14 years teaching to fly, I never had to teach not to inadvertently actuate a correctly place flap lever or switch. You can also put the MP gauge behind the wheel at the bottom of the left panel, and the rev counter at the far right, like in some certified ships. Some aircraft builders take pride at confusing pilots. And yet, human factors and ergonomics have improved since WW I ;-))) http://contrails.free.fr/instruments_ergo.php Best regards, Gilles Thesee Grenoble, France http://contrails.free.fr ________________________________ Message 34 ____________________________________ Time: 02:35:11 PM PST US From: Brian Lloyd Subject: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: Brian Lloyd A lot of people seem to want to move functions onto their stick or their throttle. I would counsel some thought about how you use that function before you rush to put it on your stick. The first question is; how much do you use that function? One of the popular functions to put on the stick seems to be the IDENT function of the transponder. How often does ATC ask you to squawk IDENT? Not very often. How hard is it to reach over and press the ident button on the xpdr? Probably not too hard. An IDENT button on your stick or yoke requires you do add wiring and a switch. How much is that likely to gain you in terms of ease of use? I bet that the total amount of effort required to push the IDENT button every time ATC asks you for the life of your airplane is less than the time it will take you to wire the switch. Not a great return on investment. Now, about the flaps. Again, this is not something you are going to be using over and over again in one flight. You are going to use it once or twice per flight. Again, no big impact to have to move your hand to a flap switch on the panel or near your throttle. Likewise something like that radio active/standby frequency toggle. Since you have to put your hand up to the radio to change the frequency anyway, you may as well press the button to toggle between active and standby. So think about the kinds of things you use over and over again in flight. The short list that comes to mind: 1. radio PTT 2. intercom PTT 3. speed brakes 4. trim 5. weapons select 6. weapons release There just isn't a whole lot more you are going to use enough to justify putting it on the stick or throttle so maybe you just want to keep it simple. Brian ________________________________ Message 35 ____________________________________ Time: 03:40:29 PM PST US From: Subject: Re: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: ---- Brian Lloyd wrote: > --> AeroElectric-List message posted by: Brian Lloyd > > A lot of people seem to want to move functions onto their stick or their > throttle. I would counsel some thought about how you use that function > before you rush to put it on your stick. > > The first question is; how much do you use that function? One of the > popular functions to put on the stick seems to be the IDENT function of > the transponder. How often does ATC ask you to squawk IDENT? Not very > often. How hard is it to reach over and press the ident button on the > xpdr? Probably not too hard. An IDENT button on your stick or yoke > requires you do add wiring and a switch. How much is that likely to gain > you in terms of ease of use? I bet that the total amount of effort > required to push the IDENT button every time ATC asks you for the life > of your airplane is less than the time it will take you to wire the > switch. Not a great return on investment. > > Now, about the flaps. Again, this is not something you are going to be > using over and over again in one flight. You are going to use it once or > twice per flight. Again, no big impact to have to move your hand to a > flap switch on the panel or near your throttle. > > Likewise something like that radio active/standby frequency toggle. > Since you have to put your hand up to the radio to change the frequency > anyway, you may as well press the button to toggle between active and > standby. > > So think about the kinds of things you use over and over again in > flight. The short list that comes to mind: > > 1. radio PTT > 2. intercom PTT > 3. speed brakes > 4. trim > 5. weapons select > 6. weapons release > > There just isn't a whole lot more you are going to use enough to justify > putting it on the stick or throttle so maybe you just want to keep it > simple. > > Brian Listers, I suggest that having radio station Flip/Flop and Station Scan switch ( a single pole double throw momentary switch) is a very useful item to have on the stick. If the radio stack is located away from the co-pilot, it is a necessity for them. Charlie Kuss ________________________________ Message 36 ____________________________________ Time: 03:40:30 PM PST US From: Subject: Re: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: ---- Brian Lloyd wrote: > --> AeroElectric-List message posted by: Brian Lloyd > > A lot of people seem to want to move functions onto their stick or their > throttle. I would counsel some thought about how you use that function > before you rush to put it on your stick. > > The first question is; how much do you use that function? One of the > popular functions to put on the stick seems to be the IDENT function of > the transponder. How often does ATC ask you to squawk IDENT? Not very > often. How hard is it to reach over and press the ident button on the > xpdr? Probably not too hard. An IDENT button on your stick or yoke > requires you do add wiring and a switch. How much is that likely to gain > you in terms of ease of use? I bet that the total amount of effort > required to push the IDENT button every time ATC asks you for the life > of your airplane is less than the time it will take you to wire the > switch. Not a great return on investment. > > Now, about the flaps. Again, this is not something you are going to be > using over and over again in one flight. You are going to use it once or > twice per flight. Again, no big impact to have to move your hand to a > flap switch on the panel or near your throttle. > > Likewise something like that radio active/standby frequency toggle. > Since you have to put your hand up to the radio to change the frequency > anyway, you may as well press the button to toggle between active and > standby. > > So think about the kinds of things you use over and over again in > flight. The short list that comes to mind: > > 1. radio PTT > 2. intercom PTT > 3. speed brakes > 4. trim > 5. weapons select > 6. weapons release > > There just isn't a whole lot more you are going to use enough to justify > putting it on the stick or throttle so maybe you just want to keep it > simple. > > Brian Listers, I suggest that having radio station Flip/Flop and Station Scan switch ( a single pole double throw momentary switch) is a very useful item to have on the stick. If the radio stack is located away from the co-pilot, it is a necessity for them. Charlie Kuss ________________________________ Message 37 ____________________________________ Time: 03:44:07 PM PST US From: FLYaDIVE@aol.com Subject: Re: AeroElectric-List: Flap switches/relay wiring --> AeroElectric-List message posted by: FLYaDIVE@aol.com In a message dated 8/22/06 5:13:32 PM Eastern Daylight Time, Gilles.Thesee@ac-grenoble.fr writes: > If you have to learn not to actuate the switch, then it is misplaced. In > 14 years teaching to fly, I never had to teach not to inadvertently > actuate a correctly place flap lever or switch. > You can also put the MP gauge behind the wheel at the bottom of the left > panel, and the rev counter at the far right, like in some certified > ships. Some aircraft builders take pride at confusing pilots. > > And yet, human factors and ergonomics have improved since WW I ;-))) > http://contrails.free.fr/instruments_ergo.php > > Best regards, > Gilles Thesee > Grenoble, France > http://contrails.free.fr ========================== Gill: You are right! And to that I would add the problem twin Beech have with the placement of the Gear switch (saw that accident). And how may of your students have pulled MIXTURE instead if throttle? But, I'd bet the fellow did not brief his wife on the Copilot Check List. Take a look in current military aircraft ... Notice the MANY safety switches? F-4 use to pickle their entire Su-21 rocket pod because their gloves got caught on the switch ... Whoops Did I do that! There was an accident at a local airport ... Plane - C-150 Pilot - CFI Passenger - TV Cameraman The accident happened on take off ... As the plane was climbing out and luckily the plane did not go past the end of the runway. Lucky only because the end of the runway was a major 4 lane highway. The passenger moved his camera bag right on top of the (panel mounted) flap switch ... C-150's don't climb well with 40 Deg of flaps! All survived, but I'd bet that CFI does not get a job with a major airline. This leads to the professor's quote: "The only way to make something idiot proof, is to remove the idiot." Barry "Chop'd Liver" "Show them the first time, correct them the second time, kick them the third time." Yamashiada ________________________________ Message 38 ____________________________________ Time: 04:15:45 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:57 PM 8/22/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Tony Babb" > >Dave, > >As a neophyte thanks for leading me to the bottom line here - THANK YOU !! > >Tony > >-----Original Message----- >From: owner-aeroelectric-list-server@matronics.com >[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Dave >N6030X >Sent: Tuesday, August 22, 2006 10:53 AM >To: aeroelectric-list@matronics.com >Subject: Re: AeroElectric-List: Re: MOV's > > >--> AeroElectric-List message posted by: Dave N6030X >--> > >Ok, so translated into complete neophyte-speak, for the rest of "us", >this means: > >" >1. The experts disagree (as they do in high vs low wing) >2. You can use a diode or a transorb, but do use something. >3. Pick whichever you find cheaper and more readily available. >4. A transorb can be wired up either direction, while a diode must be > wired with the correct polarity. Actually, Transorbs come in two flavors . . . uni-polar and bi-polar. Something else to keep in mind is that a Transorb is just a special variant of a zener diode. Zeners are intended for continuous duty, relatively hi energy dissipation, voltage regulation or limiting tasks and have sharper regulation characteristics than Transorbs which are optimized for short duration, relatively hi power but low energy clamping tasks. They have a might higher dynamic resistance than zeners while performing their "regulation" function. Many companies supply relays with diodes and/or diode-zener combinations already installed inside their product. For example, the S702-1 intermittent duty contactor we used to sell has the coil suppression diode built in. If one checks out the data sheet at: http://www.azettler.com/pdfs/technical_notes.pdf on page 6 we see various coil suppression techniques discussed. Incidently, the "varistor" technique at the bottom of the page is the MOV technique we've been discussing. Note that the diode-only technique is shown along with a notice that it offers long delays for release time which is consistent with the experimental data I posted earlier. Note further that there is no suggestion that this technique not be used in favor of another technique. One presumes that choices are driven by differences in circuit performance and not by a desire to minimize stresses harmful to the relay. On the same page we see the zener (transorb)-diode technique. Note that a diode is used with a zener because it too is a uni-polar device. The diode is necessary to prevent forward conduction of the zener during times the relay is energized but still allows the zener to do its voltage clamping thing during coil-spike-time. One could, of course, use the bi-polar Transorb in place of a zener (transorb)-diode network. Bob . . . ________________________________ Message 39 ____________________________________ Time: 06:42:37 PM PST US From: "Peter Pengilly" Subject: RE: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: "Peter Pengilly" >So think about the kinds of things you use over and over again in >flight. The short list that comes to mind: > >1. radio PTT >2. intercom PTT >3. speed brakes >4. trim >5. weapons select >6. weapons release >There just isn't a whole lot more you are going to use enough to justify >putting it on the stick or throttle so maybe you just want to keep it >simple. Well, if we're going off on this tack I would add -Master mode select (air-to-ground, air-to-air, nav, approach) -AAM cage/uncage -Waypoint step up -Weapon aiming sensor select -Sensor slew/zoom/track/scan -Autopilot/stabs disconnect -Chaff/flare release What's appropriate to small airplanes (as well as those Brian mentioned)? Autopilot disconnect Possibly waypoint step up if your GPS/EFIS allows Where's the flap switch? On the panel in front of the throttle Radio tune/flip flop? On the up front controller (just below the HUD) Waypoint insert/select? Up front controller So for those actions that are done a lot (radio tune), where you have to look in, put the box just below the glare shield so that you move your eyes a minimum distance. Might as well learn something from all those taxpayer $$$! BTW some 2 seat Pitts' had the PTT on the throttle - always seemed like a good idea if you expect to have an autopilot in the right seat. Pete ________________________________ Message 40 ____________________________________ Time: 07:29:14 PM PST US From: "Rob Wright" Subject: RE: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: "Rob Wright" Hear, hear! Maybe add AP disconnect in lieu of the weapons switches.... Do not archive Rob Wright -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Brian Lloyd Sent: Tuesday, August 22, 2006 4:35 PM Subject: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: Brian Lloyd A lot of people seem to want to move functions onto their stick or their throttle. I would counsel some thought about how you use that function before you rush to put it on your stick. The first question is; how much do you use that function? One of the popular functions to put on the stick seems to be the IDENT function of the transponder. How often does ATC ask you to squawk IDENT? Not very often. How hard is it to reach over and press the ident button on the xpdr? Probably not too hard. An IDENT button on your stick or yoke requires you do add wiring and a switch. How much is that likely to gain you in terms of ease of use? I bet that the total amount of effort required to push the IDENT button every time ATC asks you for the life of your airplane is less than the time it will take you to wire the switch. Not a great return on investment. Now, about the flaps. Again, this is not something you are going to be using over and over again in one flight. You are going to use it once or twice per flight. Again, no big impact to have to move your hand to a flap switch on the panel or near your throttle. Likewise something like that radio active/standby frequency toggle. Since you have to put your hand up to the radio to change the frequency anyway, you may as well press the button to toggle between active and standby. So think about the kinds of things you use over and over again in flight. The short list that comes to mind: 1. radio PTT 2. intercom PTT 3. speed brakes 4. trim 5. weapons select 6. weapons release There just isn't a whole lot more you are going to use enough to justify putting it on the stick or throttle so maybe you just want to keep it simple. Brian ________________________________ Message 41 ____________________________________ Time: 07:34:38 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:33 PM 8/22/2006 -0700, you wrote: --> AeroElectric-List message posted by: "Paul Messinger" Comments by your numbers. 1. I only know one "expert" that disagrees with the use of transorbs. I am sure they are more but the overwhelming majority of my engineering associates agree with the "true experts in the field" of relays and contacts etc. Who's claiming to be an expert? Please cite the writings of any other individual who has measured, illustrated and explained variabilities and their effects in the manner which I've offered. The name, job title and organization of any such individual are unimportant. The numbers and explanations are. Good data and experimental technique stands by itself because it (1) makes sense and/or (2) is easily supported (or refuted) by repeating the experiment. I can demonstrate at least three cases in the past 8 years where the best that some big-name companies could bring to bear on high dollar problems was insufficient to the task. Instead of getting their fast-turn advice on how best to deduce failures of their products, it took me months and in one case years to figure it out for myself. In the end, I knew more about some aspects of their product than they did. 2. Sort of true in most cases. Not usually true with contactor type relays switching inductive loads for example. There are two issues the coil inductive kick that must be addressed that affects the driver of the coil and the relay contacts which can affect the switched load by delays (seldom) and slow opening which power contactors really have a large delay in many cases and the duration and magnitude of the slow opening of a large inductive load can be damaging. If I read this correctly, you're citing the occasional system performance issue where a 12 mS dropout delay is okay but a 60+ mS delay causes problems. Yes, I've had to deal with a few systems where multiple relays could get into operating "races" and produce unpredictable and unsatisfactory performance. I know of no situation in OBAM aviation where this could be an issue. However, in the last sentence you seem to be speaking of contact spreading velocity which I've shown is mildly affected by the form of coil spike suppression. 3. Sure quality and use is trumped by price. 5 cents is better than 25 cents. Using the same logic go to your rat shack and get plastic crimp terminals as they are cheaper and easier to find. Price has nothing to do with the design points under discussion. MOVs were attractive to me early on in spite of their price BECAUSE they were bi-directional devices. I reasoned that use of the MOV would prevent the occasional accidental mis-wiring that is possible with the decidedly uni-directional nature of diodes. However, they did not perform as well as diodes for the purpose of reducing stress on the controlling switch. Further, they were hard to find in very low conduction voltage ratings. I abandoned them in my writings after a few years in favor of readily available, lower cost, better performing, plain vanilla diode. 4. Transorbs are both uni-directional and bi-directional. True in one case and polarity is important in the other. However a uni-directional transorb is no better than a diode, and is a diode in that use. In fact, you cannot use a uni-directional Transorb (or plain-vanilla zener) unless combined with a diode to prevent forward conduction as shown in multitudes of catalogs and literature on relays. Paul At 11:51 AM 8/22/2006, you wrote: --> AeroElectric-List message posted by: "Paul Messinger" I get them for as little as under 25 cents each in qty of one (15 cents each for 100). All industrial electronic suppliers stock them in many types and brands. $30 will get you 100 parts including shipping in some cases. The cost difference is not significant in the big picture. Agreed. Let us leave cost out of it. Eric provides a value added KIT of parts etc its up to you to convert convenience for absolute cost. (Eric also posted the exact part number for those who wanted to get just the diodes from most any source as above) Relays with internal diodes are available simply because of demand, not for technical reasons. Engineers resist change and if it seems to work why change? ???? Really. You don't speak very highly of engineers. Stuck in ruts (do they never seek to broaden their horizons?) Further, they're willing to accept anything that "seems" to work. Don't you think it's incumbent upon the savvy engineer to KNOW how and why things work and not rely on mortal perception? Perhaps I benefited from not having finished school if I avoided that upper level class: Ruts and Perceptions 425 - Recipes for Failure. Transorbs are better or (no worse in some opinions) and work in 100% of the cases. Its a "no brainier" for some of us. How are they "better"? I've never said that they SHOULD NOT be used or that they were somehow inferior. The only thing I've said and demonstrated was that there is no measurable value FOR using them. The difference between NO suppression (open circuit) and the most aggressive suppression (diode) was a spread of 10% in arc-time during contact opening. A diode-transorb combo would fall somewhere in between. This means that the delta for diode-transorb versus diode-only could be as little as 1% and maybe as much a 9% . . . that was the point of the experiment, to put some bounds on a spread. Further, it's the only claim being made from analysis of the data. While they may not appear to make a difference in a 5 amp resistive load with a small relay, Transorbs are proven to have a large advantage in inductive and larger current loads with larger or different type relays. Please cite the experiments and the resulting data. Keep in mind that off-the-shelf relays of ALL sizes are available with nothing, diode-zener and diode only coil suppression. If one technique were so decidedly favorable over another technique, why hasn't the relay and contactor industry all jumped onto one bandwagon as your "entire world" citation below suggests they should? But so what! Bob has his "repeatable" test of one and is convinced he is right. I gathered data on one relay and tested three others of various sizes from 2 to 30 or so amps. The measured results with respect to effects on contact spreading velocity were similar. If the test was poorly crafted then it should be no big deal to demonstrate my error. One size (test) does not fit all cases and perhaps its 90% (for diodes) for the average aircraft but clearly not 99.99% based on MY own lab repeatable tests. Please share the data of your tests. What size relay would you like to see data on? I have some real honkers. I think I could do a 400A interrupt experiment for you. Let us compare notes. The entire world, North America, and Europe for example, ALL say the same thing that Eric referenced about Diodes vs. Transorbs etc. Just who is out of step here???? Please cite the literature. You've cited applications literature on Transorbs before that was shown to be overstated or when it came to over-voltage and load-dump mitigation. You once advocated a generous sprinkling of Transorbs on the bus . . . one for every breaker as I recall. The Transorb is a high power, low energy device well suited for mitigating short duration events . . . lightning strikes and ESD. I'm well aware of their usefulness. I stuck an array of Transorbs on an electro-whizzy just this weekend so that I could pass and ESD test in the lab tomorrow morning. At the same time, others here on the list have shown that the Transorb is not suited to a load-dump mitigation without deliberate impedance limiting of the energy source (just like the manual says). In this discussion, we're definitely in the short duration, low energy realm where a Transorb thrives. But I'll say again, I'm not campaigning against Transorbs for this application. I'm only stating that there's no compelling evidence support superior performance over the lowly diode for coil suppression when it comes to fending off the contact-eating gremlins. There are hundreds in every modern auto. Given the number of autos made each year and yes Transorbs do cost more than simple diodes why would auto makers spend millions of $$ every year for them if the diode was as good and they could save all that money with diodes. Perhaps they know something not stated on this list?? Perhaps you have special knowledge of the reasoning behind their use? Yes, we use hundreds of them on airplanes too, but they're not used on large contactors in lieu of diodes . . . for the reasons I've cited. If you look at the available data including the many references and read and understand the available info, its far more compelling than appears on the surface. Let us not talk about "surface" or "appearances". How about physics of test setups and numbers derived therefrom. Is "good enough" OK if you can get better for little more? I am unwilling to have another useless debate. It ends up with a lot of words/heat etc. and no opinion ever gets changed. It is not my wish to convince you or anyone else of anything sir. It's my intent to explain things and support my explanations with demonstrable fact and logical conclusions based on those facts. If I am in error, nobody would be happier to know the nature of the error than I. Go to the lab sir. Show us the data you've collected. I need to know how I screwed up. You name the test conditions and I'll repeat the test so we can compare results. This is where the debate becomes useful . . . not to you or I but to those who choose to read it and deduce facts of the matter for themselves. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 42 ____________________________________ Time: 08:12:46 PM PST US From: "Bruce Gray" Subject: RE: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: "Bruce Gray" In my rather sedate Glasair III I have speed brakes, coolie hat trim (aileron and elevator), CWS (control wheel steering for the AP), PTT, Xponder Ident, and AP disconnect. The CP has duplicate switches but all except PTT are disabled by a panel mounted transfer switch. Bruce www.glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Rob Wright Sent: Tuesday, August 22, 2006 10:28 PM Subject: RE: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: "Rob Wright" Hear, hear! Maybe add AP disconnect in lieu of the weapons switches.... Do not archive Rob Wright -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Brian Lloyd Sent: Tuesday, August 22, 2006 4:35 PM Subject: Ergonomics (was: AeroElectric-List: Flap switches/relay wiring) --> AeroElectric-List message posted by: Brian Lloyd A lot of people seem to want to move functions onto their stick or their throttle. I would counsel some thought about how you use that function before you rush to put it on your stick. The first question is; how much do you use that function? One of the popular functions to put on the stick seems to be the IDENT function of the transponder. How often does ATC ask you to squawk IDENT? Not very often. How hard is it to reach over and press the ident button on the xpdr? Probably not too hard. An IDENT button on your stick or yoke requires you do add wiring and a switch. How much is that likely to gain you in terms of ease of use? I bet that the total amount of effort required to push the IDENT button every time ATC asks you for the life of your airplane is less than the time it will take you to wire the switch. Not a great return on investment. Now, about the flaps. Again, this is not something you are going to be using over and over again in one flight. You are going to use it once or twice per flight. Again, no big impact to have to move your hand to a flap switch on the panel or near your throttle. Likewise something like that radio active/standby frequency toggle. Since you have to put your hand up to the radio to change the frequency anyway, you may as well press the button to toggle between active and standby. So think about the kinds of things you use over and over again in flight. The short list that comes to mind: 1. radio PTT 2. intercom PTT 3. speed brakes 4. trim 5. weapons select 6. weapons release There just isn't a whole lot more you are going to use enough to justify putting it on the stick or throttle so maybe you just want to keep it simple. Brian ________________________________ Message 43 ____________________________________ Time: 08:24:00 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:52 PM 8/22/2006 -0400, you wrote: >--> AeroElectric-List message posted by: Ken > >True for a bi-directional transorb. But just to muddy the waters, I kind >of like the more common uni-directional transorbs. They will still help >with positive spikes (if you believe in positive spikes ;) ). Used across >a contactor coil, they may delay the opening a smidge compared to a >bidirectional transorb, but I suspect that, like the common diode, they >are more effective at preventing negative spikes (if you believe in >negative spikes comining off contactor coils ;) ). It seems to me that >an 18 volt bidirectional transorb may still let negative spikes through >that are large enough to damage electrolytic capacitors and perhaps solid >state devices, if there is no battery in the circuit. I guess I used >diodes on all the contactors and then added a few transorbs on the b-lead >just because I could... > >Are automobiles incorporating transorbs within some devices now? I've >never come across one yet that I've noticed. > >Ken > >>4. A transorb can be wired up either direction, while a diode must be >>wired with the correct polarity. >>" A contactor coil can generate spikes of either polarity. It depends on how you switch it. Here's a trace I took off the coil of a Cole-Hersee battery contactor with no coil suppression. I dug through the archives and found some more data on devices common to the OBAM aviation electrical systems. See: http://www.aeroelectric.com/Pictures/Curves/CH_Bus_Noise_w_0p1_Cap.gif Here you see a 300+ volt POSITIVE spike because the controlling switch (battery master) is in the ground lead. Note that with as little as 0.1 uF capacitor on the supply plus whatever the bench supply (3A regulated) impedance was, the spike noise coupled to the bus was on the order of one or two volts high. And this may have been a test setup artifact (meaning smaller than observed). The point of this setup was to show that coil spikes are a danger only to the controlling device (in this case, battery master switch) and NOT to other devices on the bus. These spikes DO NOT propagate about the system on the lookout for vulnerable electro-whizzies. The next trace . . . http://www.aeroelectric.com/Pictures/Curves/CH_w_120_Ohm.gif shows the coil suppression benefits of a simple resistor. In this case, 120 ohms. The spike is notably smaller, only 90 volts or so and again, the spike coupled to the bus was tiny by comparison and probably not "real". Note the 22 mS release time for the contactor. The next trace . . . http://www.aeroelectric.com/Pictures/Curves/CH_w_1n5400.gif shows what happens with the plain diode spike suppressor. Note the very slight upward inflection of trace #2 above bus voltage where the coil energy is staining against the diode's forward voltage drop as positive going spike is clamped off. Note the 75 mS release time. The next trace . . . http://www.aeroelectric.com/Pictures/Curves/CH_w_2x18v_Transorbs.gif shows the results of a pair of 18v Transorbs (or zeners) hooked back to back to emulate the bi-directional device. Here the spike clamps off at an expected level of about 18 volts above bus voltage and we see a release time of about 14 mS. The next trace . . . http://www.aeroelectric.com/Pictures/Curves/Cole-Hersee_without_Diode.gif Shows a Cole-Hersee contactor release time ploted at some other time without a diode but this time, I captured the release time of 11 mS. The next trace . . . http://www.aeroelectric.com/Pictures/Curves/Cole-Hersee_with_Diode.gif is for the same relay and shows a 53 mS release time, again about 5x the no-diode time noted above. This data is proprotionally consistant with numbers I posted for the smaller relay earlier. Note also that one experiment with the CH contactor and diode yielded a 75 mS release time while the second was only 53 mS. This variability is to be expected and is driven by many factors including contactor temperature and manufacturing variables. The effects of any one suppression technique can be accurately compared only when all techniques are used on the same contactor and done with some effort to keep the contactor temperature constant for each experiment. Note that NONE of these traces went to the issue of contact spreading velocity and resulting arc durations . . . only changes in release time for the various techniques with a peripheral look at spike propagation to the bus. This series of traces serves to illustrate only the variability of release time which a number of articles have mistakenly assumed that proportionate decreases in contact spreading velocity automatically follow. I'll suggest that the assumed proportionality does not exist and that their is no demonstrable advantage for using one suppression technique over another in terms of performance. That suggests we're free to choose techniques based on price. The plain vanilla diode is hard to beat for price and wide spread availability. However, I'd be delighted to be shown wrong if my suggestion is in error. Bob . . . ________________________________ Message 44 ____________________________________ Time: 08:49:15 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Paul Messinger" I cannot let this get past as your statement is in fact TOTALLY technically incorrect (vs opinions). Below requests for links must exclude your own as they need to be unbiased! ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Tuesday, August 22, 2006 7:32 PM Subject: Re: AeroElectric-List: Re: MOV's > In fact, you cannot use a uni-directional Transorb (or > plain-vanilla zener) unless combined with a diode to > prevent forward conduction as shown in multitudes of catalogs > and literature on relays. Please tell the LIST (specific link please) where a 50V uni-directional Transorb device (properly connected) is different from a 50v diode in coil supression or forward conduction for that matter. Of course if you use a Transorb alone as a diode its no better than a diode so that configuration is not addressed. Both forward conduct and both block at voltages under 50V. Heck the common 50V Zener is the same in that respect. Both also conduct in both directions if the breakdown V is exceeded. I thought we agreed the Transorb is like a zener with the special charactericts (specifically its designed for HUGE " zener current" for a very short time and perhaps 10,000 times faster as the normal Zener which is not capable of fast enough response to perform the function of transient supression. Please show me ANY reference that supports your statement (link please) that a single transorb is NOT exactly like a diode when used in relay coil supression just by its self and PROPERLY connected to work as a diode. Or a Zener for that matter. In a pinch a zener or a uni-directional transorb can act as a diode in non critical circuits as long as the Voltage rating is observed. Finally is there (in the industry) any statements that state that a diode is BETTER than a Transorb as you suggest?? (Please supply a link) I sure have not seen any and I have looked as has Eric and together we have found many to look at here and in Europe. EVERY reference we have found stated the diode is not as good as the transorb, or (Zener/diode combination). In fact the LEAST preferred part on EVERY list is the diode. Not that diodes work OK in most applications usually discussed on this list Paul ________________________________ Message 45 ____________________________________ Time: 08:49:15 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Paul Messinger" As I have stated in my original post which you (apparently do not want to respond to) I will not get into a debate with you ever again (actually on ANY subject) and this subject (transorbs) has been debated between us starting nearly 10 years ago. If you truly are interested in the reasons (pros and cons) of the various types of coil suppression please consider reviewing the references Eric posted as your reference had little info other than to illustrate the types of suppression relay delays. Yes (as you have stated) the total circuit (not just the coil) drives the suppression method and Transorbs always work and diodes only usually work. I will not respond to your comments below (however erroneous some may be) as there is no point. Paul ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Tuesday, August 22, 2006 7:32 PM Subject: Re: AeroElectric-List: Re: MOV's > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > At 01:33 PM 8/22/2006 -0700, you wrote: > > --> AeroElectric-List message posted by: "Paul Messinger" > > > Comments by your numbers. > > 1. I only know one "expert" that disagrees with the use of transorbs. I am > sure they are more but the overwhelming majority of my engineering > associates agree with the "true experts in the field" of relays and > contacts etc. > > Who's claiming to be an expert? Please cite the writings > of any other individual who has measured, illustrated and > explained variabilities and their effects in the manner > which I've offered. The name, job title and organization > of any such individual are unimportant. The numbers and > explanations are. Good data and experimental technique > stands by itself because it (1) makes sense and/or (2) > is easily supported (or refuted) by repeating the experiment. > > I can demonstrate at least three cases in the past 8 years > where the best that some big-name companies could bring to > bear on high dollar problems was insufficient to the task. > Instead of getting their fast-turn advice on how best to > deduce failures of their products, it took me months and > in one case years to figure it out for myself. In the end, > I knew more about some aspects of their product than they > did. > > > 2. Sort of true in most cases. Not usually true with contactor type relays > switching inductive loads for example. There are two issues the coil > inductive kick that must be addressed that affects the driver of the coil > and the relay contacts which can affect the switched load by delays > (seldom) and slow opening which power contactors really have a large delay > in many cases and the duration and magnitude of the slow opening of a > large inductive load can be damaging. > > If I read this correctly, you're citing the occasional > system performance issue where a 12 mS dropout delay > is okay but a 60+ mS delay causes problems. Yes, I've > had to deal with a few systems where multiple relays could > get into operating "races" and produce unpredictable and > unsatisfactory performance. I know of no situation in OBAM > aviation where this could be an issue. > > However, in the last sentence you seem to be speaking of > contact spreading velocity which I've shown is mildly > affected by the form of coil spike suppression. > > > 3. Sure quality and use is trumped by price. 5 cents is better than 25 > cents. Using the same logic go to your rat shack and get plastic crimp > terminals as they are cheaper and easier to find. > > Price has nothing to do with the design points under > discussion. MOVs were attractive to me early on in spite > of their price BECAUSE they were bi-directional devices. > I reasoned that use of the MOV would prevent the occasional > accidental mis-wiring that is possible with the decidedly > uni-directional nature of diodes. However, they did not > perform as well as diodes for the purpose of reducing stress > on the controlling switch. Further, they were hard to find > in very low conduction voltage ratings. > > I abandoned them in my writings after a few years in > favor of readily available, lower cost, better performing, > plain vanilla diode. > > > 4. Transorbs are both uni-directional and bi-directional. True in one case > and polarity is important in the other. > > However a uni-directional transorb is no better than a diode, and is a > diode in that use. > > In fact, you cannot use a uni-directional Transorb (or > plain-vanilla zener) unless combined with a diode to > prevent forward conduction as shown in multitudes of catalogs > and literature on relays. > > Paul > > At 11:51 AM 8/22/2006, you wrote: > --> AeroElectric-List message posted by: "Paul Messinger" > > > I get them for as little as under 25 cents each in qty of one (15 cents > each for 100). All industrial electronic suppliers stock them in many > types and brands. $30 will get you 100 parts including shipping in some > cases. The cost difference is not significant in the big picture. > > Agreed. Let us leave cost out of it. > > > Eric provides a value added KIT of parts etc its up to you to convert > convenience for absolute cost. (Eric also posted the exact part number for > those who wanted to get just the diodes from most any source as above) > > Relays with internal diodes are available simply because of demand, not > for technical reasons. Engineers resist change and if it seems to work why > change? > > ???? Really. You don't speak very highly of engineers. Stuck > in ruts (do they never seek to broaden their horizons?) Further, > they're willing to accept anything that "seems" to work. Don't > you think it's incumbent upon the savvy engineer to KNOW how > and why things work and not rely on mortal perception? Perhaps > I benefited from not having finished school if I avoided that > upper level class: Ruts and Perceptions 425 - Recipes for > Failure. > > Transorbs are better or (no worse in some opinions) and work in 100% of > the cases. Its a "no brainier" for some of us. > > How are they "better"? I've never said that they SHOULD > NOT be used or that they were somehow inferior. The only > thing I've said and demonstrated was that there is no > measurable value FOR using them. > > The difference between NO suppression (open circuit) and > the most aggressive suppression (diode) was a spread of > 10% in arc-time during contact opening. A diode-transorb > combo would fall somewhere in between. This means that > the delta for diode-transorb versus diode-only could be > as little as 1% and maybe as much a 9% . . . that was > the point of the experiment, to put some bounds on a > spread. Further, it's the only claim being made from > analysis of the data. > > While they may not appear to make a difference in a 5 amp resistive load > with a small relay, Transorbs are proven to have a large advantage in > inductive and larger current loads with larger or different type relays. > > Please cite the experiments and the resulting data. > Keep in mind that off-the-shelf relays of ALL sizes > are available with nothing, diode-zener and diode > only coil suppression. If one technique were so > decidedly favorable over another technique, why > hasn't the relay and contactor industry all jumped > onto one bandwagon as your "entire world" citation > below suggests they should? > > But so what! Bob has his "repeatable" test of one and is convinced he is > right. > > I gathered data on one relay and tested three others of various > sizes from 2 to 30 or so amps. The measured results with respect > to effects on contact spreading velocity were similar. If the test > was poorly crafted then it should be no big deal to demonstrate > my error. > > One size (test) does not fit all cases and perhaps its 90% (for diodes) > for the average aircraft but clearly not 99.99% based on MY own lab > repeatable tests. > > Please share the data of your tests. What size relay would > you like to see data on? I have some real honkers. I think I > could do a 400A interrupt experiment for you. Let us compare > notes. > > The entire world, North America, and Europe for example, ALL say the same > thing that Eric referenced about Diodes vs. Transorbs etc. Just who is out > of step here???? > > Please cite the literature. You've cited applications literature > on Transorbs before that was shown to be overstated or when it > came to over-voltage and load-dump mitigation. You once advocated > a generous sprinkling of Transorbs on the bus . . . one for every > breaker as I recall. The Transorb is a high power, low energy > device well suited for mitigating short duration events . . . > lightning strikes and ESD. I'm well aware of their usefulness. I > stuck an array of Transorbs on an electro-whizzy just this weekend > so that I could pass and ESD test in the lab tomorrow morning. > > At the same time, others here on the list have shown that the > Transorb is not suited to a load-dump mitigation without > deliberate impedance limiting of the energy source (just > like the manual says). In this discussion, we're definitely in > the short duration, low energy realm where a Transorb thrives. > > But I'll say again, I'm not campaigning against Transorbs for > this application. I'm only stating that there's no compelling > evidence support superior performance over the lowly diode for > coil suppression when it comes to fending off the contact-eating > gremlins. > > There are hundreds in every modern auto. Given the number of autos made > each year and yes Transorbs do cost more than simple diodes why would auto > makers spend millions of $$ every year for them if the diode was as good > and they could save all that money with diodes. Perhaps they know > something not stated on this list?? > > Perhaps you have special knowledge of the reasoning behind their > use? Yes, we use hundreds of them on airplanes too, but they're > not used on large contactors in lieu of diodes . . . for the > reasons I've cited. > > If you look at the available data including the many references and read > and understand the available info, its far more compelling than appears on > the surface. > > Let us not talk about "surface" or "appearances". How about > physics of test setups and numbers derived therefrom. > > Is "good enough" OK if you can get better for little more? > > I am unwilling to have another useless debate. It ends up with a lot of > words/heat etc. and no opinion ever gets changed. > > It is not my wish to convince you or anyone else of anything > sir. It's my intent to explain things and support my explanations > with demonstrable fact and logical conclusions based on those > facts. If I am in error, nobody would be happier to know the > nature of the error than I. Go to the lab sir. Show us the > data you've collected. I need to know how I screwed up. You > name the test conditions and I'll repeat the test so we can > compare results. This is where the debate becomes useful . . . > not to you or I but to those who choose to read it and > deduce facts of the matter for themselves. > > Bob . . . > > --------------------------------------------------------- > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > --------------------------------------------------------- > > > ________________________________ Message 46 ____________________________________ Time: 08:57:37 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:46 AM 8/22/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > > > > Coil Suppression: > > > > In what aspect does the common, sub-$1, available-everywhere diode fall > > short enough to justify paying $30 for your single-source solution? > > -- > > ,|"|"|, Ernest Christley > > >Ernest, > >See both of the links I posted, > >ref: http://relays.tycoelectronics.com/kilovac/appnotes/transients.asp Okay, lets take a look at this citation . . . ---------------------------------------------- * Improving Relay Operate Time Coil suppression can have a profound effect on opening time which is usually called "release time". The citation speaks of "operate time" which is usually the time it takes for a relay to close - which is NOT affected by the popular coil suppression techniques. * Calculating Pull-in & Drop-out Voltages at High or Low Temperatures * Radiation Exposure at High Voltage; Is it a Problem? * Power Conservation Schemes * High Voltage Processing of Vacuum Relays These points are not germane to the discussion at hand and will be ignored for the moment. "When a 28 Vdc relay coil is turned off, the inductive energy stored in it can create surge voltages to 1500 volts on a DC power line. With the increased use of solid state devices which are sensitive to spikes, relay coils must be suppressed to limit voltage spikes to a maximum of 50 to 80 volts." The first paragraph uses impressive numbers . . . 1500 volts will scare the pants off most neophytes. Of course, it's easy to sign up to the notion that solid state devices should be "protected" from such horrific stresses. The paragraph ends with an assertion that bringing the offending spike down to the 50-80 volt range is the magic bullet. But there's a glaring error . . . that 1500 volt spike DOES NOT propagate out onto the bus but instead is impressed across the mechanism of the controlling device be it switch or transistor. "The measure of successful coil suppression depends on the degree to which the method affects the operation of the relay. Improper or excessive suppression can cause the relay to suffer from a long release time, slow contact transfer, and contact bounce on break. All of these conditions will increase contact arcing when load switching, which will reduce relay life dramatically." Yes, slowed transfer and bounce are potentially hard on a relay. Delayed release is not hard on relays but may have an effect on system performance in time-critical situations . . . and were talking MILLISECOND criticality. The paragraph correctly infers that arcing is the proximate cause of reduced relay life. "There are a number of common ways for a relay user to suppress relay coil transients and each has advantages and disadvantages. However, the most widely used methods utilize zener-diode and/or zener-zener combinations. These combinations are compact, provide excellent suppression, and do not affect relay release-time or contact life." We've already demonstrated that the favorably rated zener-zener technique has SOME effect on release time. It's less effect than diode only but the effect is not zero. What is inferred and not supported is that diode only has a profound effect on relay life . . . an assertion I don't understand based on experiments I've conducted over the years. I've not yet been able to confirm the assertion on any size relay I've worked with to date. If someone cares to show me an experiment that supports the assertion, I'd be pleased to know of it. In the mean time, I'm inclined to treat the words of the cited posting with skepticism. They take a couple of true statements, a false statement and then infer some golden actions to be taken based on those statements. As I stated in an earlier post, there's a LOT of writing like that in the wild . . . In this case, the errors are not harmful. There's nothing inherently wrong with the proposed "gold standard" but the writing does not foster understanding. Instead, lots of myths are launched and preached as gospel because they came from the Tyco-Amp or P&B bibles. Bob . . . ________________________________ Message 47 ____________________________________ Time: 09:42:44 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Re: MOV's/ opening arc --> AeroElectric-List message posted by: "Paul Messinger" I disagree that opening time is not significant as related to an aircraft application. I have done dozens of repeatable tests where the contact opening rate was the subject and have demonstrated the duration of the contact opening arc is extended and the arc intensity is much greater, specifically if you are looking at a big Contactor opening an inductor or generator like an alternator. This when the common diode is used across the coil. The issue of "opening time" is very important as the contact suppressor Transorb must absorb the energy from the alternator load dump over 50 ms vs. 10 ms (typical) and this means the transorb must be 5X bigger in heat rating. (The need for a contact suppressor is below a ways) The specific test set up is the contactor has either the diode or the bi-directional transorb across the coil and there is a uni-directional transorb clamping the alternator load dump on the alternator side of the contacts. The alternator is either properly running or has been failed to produce full output with no voltage control. Perhaps not clearly stated above, but the testing was done several years ago to simulate internal regulator alternators where the "B" lead was opened to protect the system (Or the pilot simply opened the "B" lead on a healthy alternator for what ever reason including the false triggering of a OV crow bar circuit. From the point of the opening of the relay coil to the end of the time the relay contacts are fully open the Transorb clipping the OV was tasked with clamping the voltage. The point is that with out the transorb to clamp the alternator output, the opening arc voltage jumped to over 100V and the open contacts continued to arc after they were fully open (this happens regardless of any OV crowbar present as the crow bar is on the other side of the open contacts). The Transorb on the alternator side clips the arc voltage during the opening process and only after the contacts were fully open and unable to restart an arc did the transorb fail short and then open. Thus the time from relay coil power off to final contact open determines the power rating of the transorb and using a diode across the coil added 40+ ms to the total time which is typically 5 times longer that the transorb must keep the alternator voltage in line if the transorb was across the coil. Further the duration and intensity of the arc was increased significantly. If the transorb was not rated high enough it failed during the process and the arc continued after the contacts were fully open. For example 50 amps for 50 ms is a lot of power for the common transorb and they fail short and then quickly fail open. Its well known that relays that are required to break DC voltages above the 40-50V range must use a arc quencher circuit or they usually will simply never stop arcing. Thus something is required to keep the arc voltage under say 35V until the contacts are well open where the contact gap is big enough to prevent a restart of the arc. My conclusion to the above tests is opening a failed internally regulated alternator where the failure was unregulated high voltage output is not as simple as some would believe and the "B" lead contactor (if not special design) has the potential to continue to arc after any type of OV protection has opened the contactor. Paul ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Tuesday, August 22, 2006 8:23 PM Subject: Re: AeroElectric-List: Re: MOV's > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > At 04:52 PM 8/22/2006 -0400, you wrote: > >>--> AeroElectric-List message posted by: Ken >> >>True for a bi-directional transorb. But just to muddy the waters, I kind >>of like the more common uni-directional transorbs. They will still help >>with positive spikes (if you believe in positive spikes ;) ). Used across >>a contactor coil, they may delay the opening a smidge compared to a >>bidirectional transorb, but I suspect that, like the common diode, they >>are more effective at preventing negative spikes (if you believe in >>negative spikes comining off contactor coils ;) ). It seems to me that >>an 18 volt bidirectional transorb may still let negative spikes through >>that are large enough to damage electrolytic capacitors and perhaps solid >>state devices, if there is no battery in the circuit. I guess I used >>diodes on all the contactors and then added a few transorbs on the b-lead >>just because I could... >> >>Are automobiles incorporating transorbs within some devices now? I've >>never come across one yet that I've noticed. >> >>Ken >> >>>4. A transorb can be wired up either direction, while a diode must be >>>wired with the correct polarity. >>>" > > A contactor coil can generate spikes of either polarity. It > depends on how you switch it. Here's a trace I took off the coil > of a Cole-Hersee battery contactor with no coil suppression. > I dug through the archives and found some more data on devices > common to the OBAM aviation electrical systems. See: > > http://www.aeroelectric.com/Pictures/Curves/CH_Bus_Noise_w_0p1_Cap.gif > > Here you see a 300+ volt POSITIVE spike because the controlling switch > (battery master) is in the ground lead. Note that with as little as > 0.1 uF capacitor on the supply plus whatever the bench supply > (3A regulated) impedance was, the spike noise coupled to the bus > was on the order of one or two volts high. And this may have been > a test setup artifact (meaning smaller than observed). The point of > this setup was to show that coil spikes are a danger only to the > controlling device (in this case, battery master switch) and NOT > to other devices on the bus. These spikes DO NOT propagate about > the system on the lookout for vulnerable electro-whizzies. > > The next trace . . . > > http://www.aeroelectric.com/Pictures/Curves/CH_w_120_Ohm.gif > > shows the coil suppression benefits of a simple resistor. In this > case, 120 ohms. The spike is notably smaller, only 90 volts > or so and again, the spike coupled to the bus was tiny by > comparison and probably not "real". Note the 22 mS release > time for the contactor. The next trace . . . > > http://www.aeroelectric.com/Pictures/Curves/CH_w_1n5400.gif > > shows what happens with the plain diode spike suppressor. > Note the very slight upward inflection of trace #2 above > bus voltage where the coil energy is staining against the > diode's forward voltage drop as positive going spike is > clamped off. Note the 75 mS release time. The next trace . . . > > http://www.aeroelectric.com/Pictures/Curves/CH_w_2x18v_Transorbs.gif > > shows the results of a pair of 18v Transorbs (or zeners) > hooked back to back to emulate the bi-directional device. > Here the spike clamps off at an expected level of about 18 volts > above bus voltage and we see a release time of about 14 mS. > The next trace . . . > > http://www.aeroelectric.com/Pictures/Curves/Cole-Hersee_without_Diode.gif > > > Shows a Cole-Hersee contactor release time ploted at some > other time without a diode but this time, I captured the > release time of 11 mS. The next trace . . . > > http://www.aeroelectric.com/Pictures/Curves/Cole-Hersee_with_Diode.gif > > > is for the same relay and shows a 53 mS release time, again > about 5x the no-diode time noted above. This data is proprotionally > consistant with numbers I posted for the smaller relay > earlier. Note also that one experiment with the CH contactor > and diode yielded a 75 mS release time while the second > was only 53 mS. This variability is to be expected and is > driven by many factors including contactor temperature and > manufacturing variables. The effects of any one suppression > technique can be accurately compared only when all techniques > are used on the same contactor and done with some effort to > keep the contactor temperature constant for each experiment. > > Note that NONE of these traces went to the issue of contact > spreading velocity and resulting arc durations . . . only changes > in release time for the various techniques with a peripheral look > at spike propagation to the bus. > > This series of traces serves to illustrate only the variability > of release time which a number of articles have mistakenly > assumed that proportionate decreases in contact spreading > velocity automatically follow. I'll suggest that the > assumed proportionality does not exist and that their is no > demonstrable advantage for using one suppression technique over > another in terms of performance. That suggests we're free to > choose techniques based on price. The plain vanilla diode is > hard to beat for price and wide spread availability. However, > I'd be delighted to be shown wrong if my suggestion is in error. > > Bob . . . > > > ________________________________ Message 48 ____________________________________ Time: 11:00:43 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:53 PM 8/22/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >I cannot let this get past as your statement is in fact TOTALLY >technically incorrect (vs opinions). > >Below requests for links must exclude your own as they need to be unbiased! > >----- Original Message ----- From: "Robert L. Nuckolls, III" > >To: >Sent: Tuesday, August 22, 2006 7:32 PM >Subject: Re: AeroElectric-List: Re: MOV's > > >> In fact, you cannot use a uni-directional Transorb (or >> plain-vanilla zener) unless combined with a diode to >> prevent forward conduction as shown in multitudes of catalogs >> and literature on relays. > >Please tell the LIST (specific link please) where a 50V uni-directional >Transorb device (properly connected) is different from a 50v diode in coil >supression or forward conduction for that matter. Okay, here's one. http://www.azettler.com/pdfs/technical_notes.pdf Check out the options on page 6. I see no instances of a single zener/transorb being suggested. How about . . http://relays.tycoelectronics.com/kilovac/appnotes/fig48.asp Again, where do we see the use of a single zener/transorb junction being suggested? >Of course if you use a Transorb alone as a diode its no better than a >diode so that configuration is not addressed. Agreed . . . but then it's not performing the zener style function that is being sought. You can certainly use the zener/transorb in this manner but why would you do that? I thought the plain-vanilla diode is now relegated to fifth rate performance in comparison to the latest and greatest answer to the airplane owners fondest dream: "Make my relays last forever". Of what value is it to have a single zener-transorb installed for the same purpose. Okay. Let's look at the drawing I posted at: http://www.aeroelectric.com/temp/Relay_Coil_Suppression.pdf In cases 1 and 2 we see an illustration of the phenomenon we're trying to control . . . tame the killer spike. In cases 3 and 4 we see the effects of the plain vanilla diode and it's ability to limit the coil collapse spike to under 1 volt. >Both forward conduct and both block at voltages under 50V. Heck the common >50V Zener is the same in that respect. In case 5 I show the only way a single transorb or zener can be employed in coil suppression. It's cathode must face the + side of the relay coil and, of course, the breakdown voltage of the device must exceed supply voltage. In the energized state, the zener is reverse biased at some point below breakdown voltage. In case 6, the coil's field collapse applies forward bias to the zener and it conducts just as an ordinary diode would as illustrated in case 4 above. I'll confess that my statement was in error to the effect that one MAY use a single zener/transorb but it's effect is no different than having used a plain vanilla diode so applying a zener in this manner is senseless in terms of using the zener's unique characteristics to achieve some design goal that a diode wont do. In case 7 and 8 I show the industry wide practice of adding both diode and zener in series but with the zener now turned over. In case 7, the diode prevents forward conduction of the zener during the energized state. In case 8 the coil's field collapse now forward biases the diode and reverse biases the zener such that it's now expected to conduct at some selected voltage to sink the coil's inductive energy. >Both also conduct in both directions if the breakdown V is exceeded. I >thought we agreed the Transorb is like a zener with the special >charactericts (specifically its designed for HUGE " zener current" for a >very short time and perhaps 10,000 times faster as the normal Zener which >is not capable of fast enough response to perform the function of >transient supression. Really? Zeners have been used in this application for decades. The techniques illustrated in cases 7/8 were developed and in service long before the advent of Transorbs. The relay coil spike is a rather sedate event compared to ESD and lightning and the plain zener's switching times have been and are still adequate to the task. >Please show me ANY reference that supports your statement (link please) >that a single transorb is NOT exactly like a diode when used in relay coil >supression just by its self and PROPERLY connected to work as a diode. Or >a Zener for that matter. > >In a pinch a zener or a uni-directional transorb can act as a diode in non >critical circuits as long as the Voltage rating is observed. Absolutely . . . and I can hold my pants up with a dab of super-glue on my butt. The question remains, why would one do that on purpose? >Finally is there (in the industry) any statements that state that a diode >is BETTER than a Transorb as you suggest?? I didn't say that. I said that there is no compelling reason to support the notion that diodes alone have a profound effect on relay service life which is the mantra used to sell the more expensive transorb. Both techniques are adequate to the spike suppression task but using service life as a compelling sales pitch for transorbs is not supported by the physics. > (Please supply a link) I sure have not seen any and I have looked as > has Eric and together we have found many to look at here and in Europe. > EVERY reference we have found stated the diode is not as good as the > transorb, or (Zener/diode combination). In fact the LEAST preferred part > on EVERY list is the diode. Yup, I'll agree with that. Most folks have taken up the mantra just as many others still believe we never went to the moon, that global warming is caused by too many SUVs and that pure democracy is the best way to run a planet. A preponderance of conforming opinion does not make it correct nor alter the laws of physics. > Not that diodes work OK in most applications usually discussed on this list Oops? Quantify "OK" . . . are you suggesting that the last few hours of explanation have all been for naught? Are you suggesting that the simple diode suppression technique is really okay after all? Gee Paul, I had some glimmer of hope that I was going to badger you into doing some real science after all these years and now you've gone all wobbly on me. Bob . . . ________________________________ Message 49 ____________________________________ Time: 11:21:10 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: MOV's --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:19 PM 8/22/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >As I have stated in my original post which you (apparently do not want to >respond to) I will not get into a debate with you ever again (actually on >ANY subject) and this subject (transorbs) has been debated between us >starting nearly 10 years ago. Yup, that conversation has been enshrined in bytes at http://aeroelectric.com/articles/spike.pdf >If you truly are interested in the reasons (pros and cons) of the various >types of coil suppression please consider reviewing the references Eric >posted as your reference had little info other than to illustrate the >types of suppression relay delays. Yes (as you have stated) the total >circuit (not just the coil) drives the suppression method and Transorbs >always work and diodes only usually work. I've read those references. And I've explained what I've found in them that was in error. If you want to worship at the altars of Tyco-Amp or Potter-Brumfield based on your blind acceptance of their Word, that's your choice . . . but expect to be challenged when you preach philosophies you cannot yourself explain. You expose yourself as a propagandist and not as a teacher. >I will not respond to your comments below (however erroneous some may be) >as there is no point. If you can't be a teacher then don't get into the sandbox to throw mud. Your drive-by insinuations that errors in my posting are unworthy of your time and effort is consistent with the behavior you favored 6 years ago. You stood off and threw rocks at my explanations and NEVER offered a single alternative supported by your own explanation of the underlying physics. You had plenty to complain about but never a plan consistent with anyone else's design goals but your own. You want to play? Fine. If not, then you know the way out. The unsubscribe link is: http://www.matronics.com/subscribe/ Bob . . . ________________________________ Message 50 ____________________________________ Time: 11:47:33 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: B-lead Contactors (was MOV's) --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:47 PM 8/22/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >I disagree that opening time is not significant as related to an aircraft >application. I didn't say that opening time (contact spreading velocity) was insignificant. Obviously, the slower moving contact keeps an arc established longer. What I said was that the benefits of any other coil suppression technique were not significantly better than the simple diode with respect to arc duration in the experiments I conducted. I.e, no compelling reason to take all the diodes out and put in bi-directional transorbs or transorb-diode networks. >I have done dozens of repeatable tests where the contact opening rate was >the subject and have demonstrated the duration of the contact opening arc >is extended and the arc intensity is much greater, specifically if you are >looking at a big Contactor opening an inductor or generator like an >alternator. This when the common diode is used across the coil. You use "extended" and "intensity" and "greater" which are non quantified. How much? And how does your experience illuminate the tasks before our readers on this List? >The issue of "opening time" is very important as the contact suppressor >Transorb must absorb the energy from the alternator load dump over 50 ms >vs. 10 ms (typical) and this means the transorb must be 5X bigger in heat >rating. (The need for a contact suppressor is below a ways) Opps! Stuck your foot in it sir. If you install a transorb as in cases 7/8 then the transorb is isolated from an alternator load dump by the accompanying diode. If you install per cases 5/6 then yes, alternator load dump is impressed across the transorb in the zener mode . . . but if this technique is no better than a simple diode for coil suppression, why do it? Use a plain vanilla diode and the "problem" goes away. >The specific test set up is the contactor has either the diode or the >bi-directional transorb across the coil and there is a uni-directional >transorb clamping the alternator load dump on the alternator side of the >contacts. The alternator is either properly running or has been failed to >produce full output with no voltage control. Now were far-afield from the original discussion. You've injected a feature (alternator load dump) that is a whole new consideration having nothing to do with what I was attempting to explain earlier this evening. >Perhaps not clearly stated above, but the testing was done several years >ago to simulate internal regulator alternators where the "B" lead was >opened to protect the system (Or the pilot simply opened the "B" lead on a >healthy alternator for what ever reason including the false triggering of >a OV crow bar circuit. From the point of the opening of the relay coil to >the end of the time the relay contacts are fully open the Transorb >clipping the OV was tasked with clamping the voltage. Fine. But what does that have to do with spike suppression on relay coils? >The point is that with out the transorb to clamp the alternator output, >the opening arc voltage jumped to over 100V and the open contacts >continued to arc after they were fully open (this happens regardless of >any OV crowbar present as the crow bar is on the other side of the open >contacts). The Transorb on the alternator side clips the arc voltage >during the opening process and only after the contacts were fully open and >unable to restart an arc did the transorb fail short and then open. Thus >the time from relay coil power off to final contact open determines the >power rating of the transorb and using a diode across the coil added 40+ >ms to the total time which is typically 5 times longer that the transorb >must keep the alternator voltage in line if the transorb was across the >coil. Further the duration and intensity of the arc was increased >significantly. If the transorb was not rated high enough it failed during >the process and the arc continued after the contacts were fully open. For >example 50 amps for 50 ms is a lot of power for the common transorb and >they fail short and then quickly fail open. Yes, but you're illuminating a separate issue. If the loads on a relay's contacts are particularly antagonistic such as during the load dump phenomenon on a b-lead contactor, then one has two possibilities. Increase ratings of the contactor or limit the load dump intensity or a combination of both. But this is a special case that is only slightly related to the original discussion. Further, the use of Transorbs on the b-lead contactor in lieu of diodes is not the ultimate solution. Further, getting the b-lead opened is only part of the task. How do you propose to bring a runaway alternator to heel . . . or is the plan to let it self-destruct? >Its well known that relays that are required to break DC voltages above >the 40-50V range must use a arc quencher circuit or they usually will >simply never stop arcing. Thus something is required to keep the arc >voltage under say 35V until the contacts are well open where the contact >gap is big enough to prevent a restart of the arc. >My conclusion to the above tests is opening a failed internally regulated >alternator where the failure was unregulated high voltage output is not as >simple as some would believe and the "B" lead contactor (if not special >design) has the potential to continue to arc after any type of OV >protection has opened the contactor. Absolutely . . . and I think there's a rational way to mitigate this. If current negotiations for an alternator drive stand work out, I'll be able to get the energy data you claimed to have but could/would not share some years ago. And guess what? As soon as I have the results of the tests, they will be published here and on my website. You see, I do intend to service my duty as teacher. Bob . . .