---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 09/03/03: 21 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:26 AM - Re: Antenna tuning (Denny) 2. 12:35 AM - Master Switch Warning Light/buzzer (RVEIGHTA@aol.com) 3. 12:59 AM - Cell phone interference with avionics. (Miles Simon) 4. 01:13 AM - Re: Shielding the tach lead (mailbox bob at mail.flyboybob.com) 5. 01:15 AM - Rotax regulator question (Thesee Gilles) 6. 01:19 AM - Re: Master Switch Warning Light/buzzer (Gerry Holland) 7. 05:47 AM - Re: Wire and Fuse Size for E-bus (follow up) (Robert L. Nuckolls, III) 8. 07:26 AM - Re: Picking a new battery (Tinne maha) 9. 09:29 AM - Re: Picking a new battery (RSwanson) 10. 09:29 AM - Wiring Nulites (Dr. John Birgiolas) 11. 12:49 PM - expanded scale voltmeter and loadmeter (Sigma Eta Aero) 12. 01:37 PM - site back up . . . (Robert L. Nuckolls, III) 13. 02:28 PM - double-pole switch failure modes (czechsix@juno.com) 14. 04:19 PM - Re: expanded scale voltmeter and loadmeter (Robert L. Nuckolls, III) 15. 04:33 PM - Re: double-pole switch failure modes (Robert L. Nuckolls, III) 16. 04:48 PM - Re: site back up . . . (Neil Clayton) 17. 07:07 PM - Re: site back up . . . (Kevin Horton) 18. 08:02 PM - Re: site back up . . . (Ken Simmons) 19. 09:29 PM - Re: site back up . . . (Robert L. Nuckolls, III) 20. 10:46 PM - Internally regulated alternator (Amit Dagan) 21. 11:43 PM - Re: expanded scale voltmeter and loadmeter (John R) ________________________________ Message 1 _____________________________________ Time: 12:26:31 AM PST US From: "Denny" Subject: RE: AeroElectric-List: Antenna tuning --> AeroElectric-List message posted by: "Denny" Just a thought a rubber duck is a terrible antenna and would of course have no ground plane. Some radios will automatically cut back on output power if operating into a high SWR. maybe this is what is happening and your radio is just cutting the power back to low to fully load the meter. I would try it with a regular antenna before scraping the idea. Denny Mortensen dennymortensen@cableone.net Cozy MKIV #1145 Just starting -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Rob W M Shipley Subject: AeroElectric-List: Antenna tuning --> AeroElectric-List message posted by: "Rob W M Shipley" I need some advice. I want to make sure my antennas are well matched to my radios and with this in mind bought an Diamond SX20C SWR meter - recommended by a local Ham radio shop. It seems useless with my Yaesu handheld unless I'm doing something wrong since the cross needles barely move when I try it with the rubber ducky antenna. Is it going to give me useful results with a real antenna and a panel mount radio or do I need to return this and try and get something else. Published specs Frequency range 3.5 - 150MHz Input impedance 50 ohm Power range 30w or 300w (switched) Min power equirement 3w The Yaesu Aviator Pilot is rated at 4w output. Help and advice much appreciated. Rob Rob W M Shipley RV9A N919RV (res) Fuselage ________________________________ Message 2 _____________________________________ Time: 12:35:51 AM PST US From: RVEIGHTA@aol.com Subject: AeroElectric-List: Master Switch Warning Light/buzzer --> AeroElectric-List message posted by: RVEIGHTA@aol.com Bob, any ideas about a cheap/easy solution to the problem of leaving the master on and running down the battery? I just did it today, and it's a pain in th posterior. Like many homebuilts, my RV-8A has toggle switches for the master and L mag/elect. ignition, so it's easy to forgot to flip the master off (for me at least). Avtek has a nice unit called the "1st Alert" but it's kinda pricy at $160. It's main job is to alert you to a bad alternator, broken alternator belt, etc., but any negative flow from the battery makes the panel light flash. Another question is do you have any suggestions or recommendations for an externally mounted power plug to be used to jump start an a/c with low battery? Walt Shipley RV-8A ________________________________ Message 3 _____________________________________ Time: 12:59:55 AM PST US From: "Miles Simon" Subject: AeroElectric-List: Cell phone interference with avionics. --> AeroElectric-List message posted by: "Miles Simon" The U.K. C.A.A. have published the results of their experiments of the effects of cell phone usage on avionics in aircraft. The report is at : http://www.caa.co.uk/docs/33/CAPAP2003_03.PDF In summary, the report says that cell phones do affect avionics. Simon Miles, Europa XS. ________________________________ Message 4 _____________________________________ Time: 01:13:20 AM PST US From: "mailbox bob at mail.flyboybob.com" Subject: RE: AeroElectric-List: Shielding the tach lead --> AeroElectric-List message posted by: "mailbox bob at mail.flyboybob.com" Duncan, Is your prop the in flight adjustable version IVO prop? If so you could use a S700-2-70 DPDT (on)-on-(on) switch and wire both leads to ground in the center position. This would give you a positive ground for the prop at all times. You might try opening the prop circuit breaker and grounding both prop brushes directly to the engine. If this eliminates the noise then you could proceed to getting the S700-2-70 switch installed. If your prop is only ground adjustable and your testing tells you this is a static problem you could order one slip ring/brush set form IVO and set up a prop ground by using half of the in flight adjustable prop's electrical slip ring set and connect it to ground. Happy hunting, hope you kill this one soon! Regards, Bob Lee ______________________________ N52BL KR2 Suwanee, GA 30024 91% done only 51% to go! Phone/Fax: 770/844-7501 mailto:bob@flyboybob.com http://flyboybob.com -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of David Carter Subject: Re: AeroElectric-List: Shielding the tach lead --> AeroElectric-List message posted by: "David Carter" Duncan, Don't miss Bob's point about P static (P is for "precipitation static" which in my experience is "cloud/crystal ice particles static"). Don't get hung up on "precipitation" - just think "static electricity buildup" from prop blades rubbing through the air and building up a charge on the blades, and it not having a path to ground or into the plane and out the static dischargers - Ask the IVO prop folks or check your wiring info to see if you are supposed to have anything akin to a "grounding strap" that will carry static from the whirling prop to the stationary airframe (fiberglas plane or aluminum? - I forget what you said earlier). - In the absence of an "engineered discharge path" as above, then the static will build up until it has enough voltage built up to jump the first small gap it can "find" - at which point it jumps the small gap, making a spark - and noise - and does this faster as your prop rpm increases - so is related to rpm, but not to ignition noises, as you have correctly observed already. In the A-7, we had to put bonding straps in strategic places to assure an unbroken path for static from nose to tail to stop the electricity from jumping from one big aluminum panel to the next on its journey from nose to tail. After that fix, we could talk to each other in a formation and to folks on the ground when we were flying throught cirrus or stratus at 20,000 feet or so. If you are getting this on the ground, stationary, then static discharge wicks on the tail feathers are not going to get rid of it. If, in fact, you are getting static discharge noise from your plastic prop, then, for test purposes, you might have to try running a ground wire from the engine just aft of the prop. If we are at all close to the cause, you might have to put at least a temporary "slip ring" or "wiper" (something springy on the front of the engine case that will rub on some metal part of the prop and give the static a "quiet path" off the prop onto the engine case and thence to ground. - If that eliminates the noise, then you and the prop manufacturer will have a prototype to the prop maker's solution to HIS noise problem. - Or, thinking a bit more out of the box, put static discharger wicks on each tip of the prop blades! I wonder how long they will last? And I wonder how you can attach them without destroying or degrading the integrity of your prop? David Carter ----- Original Message ----- From: "Duncan McBride" Subject: Re: AeroElectric-List: Shielding the tach lead > --> AeroElectric-List message posted by: "Duncan McBride" > > OK great, some stuff to try. I'll walk around with the engine at idle and > see if the handheld picks up more noise anyplace. I'll get the guys at the > field to keep me from walking into the prop... and I have a fuel shutoff > so I'll disconnect the p-leads and see about that. > > The prop is a three-blade IVO lightweight, carbon over foam with the > stainless tape leading edge protectors. It was purchased new and has just > less than 70 hours, no problems with it. This is the one that has the metal > rods going down each blade that you torque to adjust the pitch. They are > torqued by cams in the hub - there could be metal working against metal but > I don't know how that wouldn't reveal itself in more evident fashion. I'll > watch it at night > > Thanks, > Duncan > > ----- Original Message ----- > From: "Robert L. Nuckolls, III" > To: > Subject: Re: AeroElectric-List: Shielding the tach lead > > > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > > > At 03:52 PM 8/2/2003 -0400, you wrote: > > >--> AeroElectric-List message posted by: "Duncan McBride" > > > > > > > > >I just got back from the field. When I disconnected the tach leads the > > >noise was the same. So I guess shielding the tach wire to the EIS won't > > >help. > > > > reasonable deduction . . . > > > > >I say white noise because it is a steady-state sort of noise, but it > > >is distinctively crackly. The volume goes up with engine rpm, the pitch > > >doesn't go up with rpm so much as the sound just becomes a more smoother > > >rasp, but louder. > > > > > > > Pulling the circuit breaker for the alternator has no > > >effect. > > > > Good data point . . . > > > > > And just today I tried a handheld (totally separate, battery > > >powered, rubber duck) and I get a slightly different version of the same > > >noise - not quite as loud, but related to engine rpm in intensity and > > >somewhat in pitch. > > > > Okay, it's radiated noise. NOT conducted. > > > > > > >Because the 760 exhibits the noise when separated from the bus, and I get > > >the same noise with a handheld, can I try to zero in on the source by > > >playing with the handheld? > > > > That might be helpful . . . > > > > > Should I test the 22,000 mfd smoothing > > >capacitor? > > > > If the noise is still there with the alternator off, > > then it has nothing to do with the smoothing capacitor. > > > > > How would I go about finding the source of the noise? > > > > Do you have a fuel shut off . . . can you kill the > > engine without access to ignition wires? If so, disconnect > > "p-lead" wires at the engine. If noise is still there, > > then something else is generating it and it's related > > to engine operation. Volume goes up with RPM but not > > so much in perceived pitch . . . what kind of prop do > > you have. Composite? Plastic? I'm stretching here but > > we might have a p-static thing. Observe prop in total > > darkness and after dark adapting your eyes for ten minutes > > or so . . . can you "see" the prop? > > > > Bob . . . > > > > > > > Until now > > >I just wanted to find a work around. Now, I want to find it, and kill > it. > > >It's beginning to cut into my good times. > > > > > >Thanks, > > >Duncan > > > > > > > > >----- Original Message ----- > > >From: "Robert L. Nuckolls, III" > > >To: > > >Subject: Re: AeroElectric-List: Shielding the tach lead > > > > > > > > > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > > > > > > > > > At 06:28 PM 8/1/2003 -0400, you wrote: > > > > >--> AeroElectric-List message posted by: "Duncan McBride" > > > > > > > > > > > > > > >I'll try to address your points in order > > > > > > > > > >Sine wave low frequency tach signal? I'm looking at the Rotax 912 > > > > >installation manual and the specs for the rev-counter are one pulse > per > > > > >revolution. The graphs on the documentation show a pretty sharp > spike of > > >at > > > > >least 5 volts at a load of 100 ohms and 75 volts at 100 kohms when at > > >5000 > > > > >rpm. The German translation is a little vague - there are two graphs > for > > > > >the 6000rpm oscillograms - one shows peak voltage at about 7V and the > > >other > > > > >about 75V. Who knows? I thought I would at least disconnect the > leads > > >at > > > > >the engine, fire it up and see if the noise goes away. If it does > I'll > > >hook > > > > >up some shielded wire (or bolt up some conduit, what the hell) > > > > > > > > Hmmm . . . different tach than the one I'm familiar with. > > > > Last one I looked at was on an ultra-light hangared at > > > > our airport. It ran the tach from ac off the "lighting coil". . . > > > > > > > > > > > > >As to who is hearing the noise, I am in my headphones for sure. It is > > > > >present when the radio and headphone connections are completely > isolated > > > > >from the aircraft and the radio is powered with a battery as you > > >suggested. > > > > >The 760 is grounded through the panel mounting screws, so I used > nylon > > > > >mounting screws and confirmed that it was not grounded. None of the > > > > >headphone jacks or PTT leads were grounded, and the PTT switch lead > went > > > > >back to the test battery, not the aircraft ground. When I had the > 760 > > > > >intercom feature hooked up, I did hear the noise when the intercom > PTT > > >was > > > > >pushed, so the problem is not exclusive to transmitting. Now I have > a > > > > >Sigtronics Portable (powered by the internal 9-volt battery) hooked > up to > > > > >the 760. When the transmit PTT is pushed I hear the very same noise > > >through > > > > >the intercom, whether it is turned on or not. However, when not > > > > >transmitting and just the VOX squelch is broken on the intercom, I do > not > > > > >hear the noise. I had the intercom converted to the high noise > version > > >and > > > > >I'm using Oregon Aero mic muffs on the headsets - this is working > pretty > > > > >well, though the Twinstar cockpit is pretty noisy. > > > > > > > > > > > > >I once thought that only I was hearing the noise and that other > planes or > > > > >the ground were not hearing it. That seems to have been inaccurate, > > > > >prompted by the report of a pilot who heard me in the pattern when > the > > > > >engine was idling. Subsequent tests confirm the transmission at > > >significant > > > > >power settings includes the raspy white-like noise. > > > > > > > > "white-like"? The electronic community would define a "white > noise" > > > > as a rushing sound, not unlike a huge waterfall heard from afar. > If > > > > your noise source is related to ignition, it's a very low > frequency > > > > popping noise, perhaps one or two pulses per revolution and its > > > > frequency goes up and down exactly tracking engine RPM. > > > > > > > > If there is a "white-like" noise associated with this problem, > > > > it's unlikely to be associated with the ignition system. If you > > > > turn the alternator off, does the noise go away? Can you hear > > > > the noise on a hand held receiver in close proximity to the > airplane? > > > > > > > > Bob . . . > > > > > > > > > > > > > > > > > > Bob . . . > > > > -------------------------------------------- > > ( Knowing about a thing is different than ) > > ( understanding it. One can know a lot ) > > ( and still understand nothing. ) > > ( C.F. Kettering ) > > -------------------------------------------- > > > > > > ________________________________ Message 5 _____________________________________ Time: 01:15:24 AM PST US From: Thesee Gilles Subject: AeroElectric-List: Rotax regulator question --> AeroElectric-List message posted by: Thesee Gilles Bob, Thanks again for all your answers about the Rotax rectifier-regulator. I understand it is a standard design. Here is a question that has been nagging me : There have been insistant rumors in our area about destroying the regulator by disconnecting it from the battery while the engine is running. Our project is wired according to fig Z16 (out of memory), with dual batteries and ABMM, and includes a 22000 F capacitor. COULD switching off the the master switch do any harm to the regulator ? Same thing for the operation of the over voltage crowbar protection ? Or can the presence of the capacitor provide some means of protection ? Thank you, Gilles ________________________________ Message 6 _____________________________________ Time: 01:19:35 AM PST US Subject: Re: AeroElectric-List: Master Switch Warning Light/buzzer From: Gerry Holland --> AeroElectric-List message posted by: Gerry Holland Walt Hi! > Another question is do you have any suggestions or recommendations for an > externally mounted power plug to be used to jump start an a/c with low > battery? I've fitted a Aux. Power on port side of Aircraft viewable from P1 seat. It's from a Race Car shop. Based around lightweight Plastic Socket with matching input Plug with pullout handle. 2 versions. 50A and 175 Amp Will carry 'jump' leads in A/C so whenever onboard power feels lazy I can get a jump start from just about any 12V device. I went for 50Amp. Cost about $25 for 50A and $40 for 175A In an effort to keep it simple I positioned to clearly see connections still made to outside world and in fact can reach forward and disconnect from Cabin. Regards Gerry Gerry Holland Europa 384 G-FIZY +44 7808 402404 gnholland@onetel.com ________________________________ Message 7 _____________________________________ Time: 05:47:32 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Wire and Fuse Size for E-bus (follow up) --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:09 PM 9/2/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > >At 09:47 PM 9/2/2003 -0400, you wrote: > >--> AeroElectric-List message posted by: "Dick Jordan" > >#1: Blue Mt. Suggests 10 AMP circuit but they advise normal load @ 4 AMPS. > > > >#2:Starting load shown; reduces to 1.2 AMPS after spooling up. > > > >#3: Xmit load shown;Receive @ .7 AMPS. > > > >If you reduce by the factors in the notes the load should be approx 12 AMPS. > > If you're really wanting the e-bus to be an endurance bus, then > I'd put the horizon gyro and EFIS on the main bus. Recall that > the purpose of the e-bus is to maximize use of limited resource > in the en route mode of flight. If you've suffered some kind of > failure that makes the e-bus most valuable, then you want to > get into the "Apollo 13" en route mode of power utilization until > you've got airport in sight. I suspect the autopilot in a > smooth air mode draws less than 3A average. Nav/Com will be > in the receive mode 99% of the time. 0.8A is too much for lighting. Dick, I forgot to ask if you are an all-electric airplane and if you plan a second alternator. IF you plan at least an SD-8 on the vacuum pump pad, then the e-bus can be planned for a larger continuous load than you would for battery only. With the SD-8, you could power the EFIS from the e-bus. The alternate feed wire/fuse goes up to 14AWG/15A Even with the earlier suggestion of 16AWG/10A, or the SD-8 supported 14AWG/15A combination, consider adding an S704-1 relay or equal to the system to control the e-bus alternate feed path from the battery bus end . . . sort of a mini-battery contactor. As a rule of thumb, we try to avoid always-hot feeders breakered at more than 5A . . . since fuses are so much faster, we could stretch that to 7A which will supply most folks e-bus with a reasonably sized, always-hot wire from battery bus. It's a good idea to provide a disconnect right at the battery bus for alternate feeds larger than 7A. I published a drawing of this some months ago for someone but until my server gets back up, I can't point you to it. Will follow up on this later today. Bob . . . ________________________________ Message 8 _____________________________________ Time: 07:26:14 AM PST US From: "Tinne maha" Subject: Re: AeroElectric-List: Picking a new battery --> AeroElectric-List message posted by: "Tinne maha" Unless you need the "ballast" it's almost a certainty that you can get by with a much smaller battery. How old will your 28 a.h. battery be by the time of first flight? What kind of battery is it? As my BC 110 SLA/RGbattery is already 5 years old ( dead) I will get a new one before I fly.Thanks to your response I'm sure I can get by electrically with a smaller battery. So now the question becomes 'How much smaller?': I don't think this is right but if Isum all the E-Bus fuse sizes on Fig Z-11 I get 28 amps. (IfIhave 4 hours of fuel that can't mean I need 4x28 AH of capacity. Obviously I'm trying to make it too simple) I know all the fuses don't draw that much all the time but how do I figure the steady state load for an alternator out scenario? Probably not an appropriate topicfor this list butI need a little direction on the Wt Balance Calcs: Could someone point me to an authority? I've an inquiry to the kit manufacturer but past answers haven't always been satisfactory or timely. Grant Krueger MSN 8: Get 6 months for $9.95/month. ________________________________ Message 9 _____________________________________ Time: 09:29:06 AM PST US From: "RSwanson" Subject: Re: AeroElectric-List: Picking a new battery --> AeroElectric-List message posted by: "RSwanson" I'm not sure what you're looking for, but try these: http://www.mrkent.com/flying/wt-bal/index.asp http://www.florintsev.com/wb/ May be of some help. R --> AeroElectric-List message posted by: "Tinne maha" ----snip--- > Probably not an appropriate topicfor this list butI need a little direction on the Wt Balance Calcs: Could someone point me to an authority? I've an inquiry to the kit manufacturer but past answers haven't always been satisfactory or timely. Grant Krueger ________________________________ Message 10 ____________________________________ Time: 09:29:22 AM PST US From: "Dr. John Birgiolas" Subject: AeroElectric-List: Wiring Nulites --> AeroElectric-List message posted by: "Dr. John Birgiolas" I have completed my 701 but for the engine and panel. I am starting the panel now and have not been looking forward to it. I have installed ringlites on four instruments, each of which has a + and - wire. Can I connect the four + wires together and connect them as one to the bus or should each wire have an individual connector? Sorry for the basic question, the first of many. I have been following the site for some time, but this is probably too basic a question. Is there a problem routing the transponder and radio antennas beside the battery cables or would it be better to route them on the opposite side of the fuselage with the headphone, mike and strobe/nav wiring? Thanks, John ________________________________ Message 11 ____________________________________ Time: 12:49:16 PM PST US From: Sigma Eta Aero Subject: AeroElectric-List: expanded scale voltmeter and loadmeter --> AeroElectric-List message posted by: Sigma Eta Aero Is the expanded scale voltmeter/loadmeter still being offered in kit or finished form and if so how can I get one? Thanks. Joa --------------------------------- ________________________________ Message 12 ____________________________________ Time: 01:37:48 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: site back up . . . --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" We got the oil changed, refilled the tank and jumpstarted the server . . . it's back up an running. While looking over the download traffic records, I noticed that access to some of the big reference documents and the CD Rom have expanded dramatically over the last two months . . . and I am pleased that so many folks are finding the data useful. Problem is that total traffic coming off our server is setting new records both for bytes transferred -and- co-location billing charges. I need to rethink how much stuff I'm going to support there, particularly in terms of things that one can find out there in the wild on the 'net. My server bill for last month was about 2x what it cost me with the last hosting service . . . the whole idea of owning our own server was to cut costs by more than half! At the moment, I think I'll have to back off on the number and size of download options and go back to offering the whole collection on an orderable CD. So, if anyone finds that a link to a previously available item doesn't work, the reason is that the item was pulled off the server. I'll be looking for a way to bring this service back . . . Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 13 ____________________________________ Time: 02:28:25 PM PST US Subject: AeroElectric-List: double-pole switch failure modes From: czechsix@juno.com --> AeroElectric-List message posted by: czechsix@juno.com Bob, In your experience, is there much value in replacing a single pole switch with a double-pole switch in terms of separating signals where you want to reduce exposure to single point failure? To elaborate a bit, the situation I'm considering involves running ground/open discretes from several pieces of equipment through a single switch in the cockpit that shuts all equipment down when actuated. The obvious concern is that there's a single-point failure mode where if the switch or any of the wires connected to it fails by shorting to ground, the whole system goes down. The wiring can be mostly isolated from this failure mode with diodes but this still leaves the single switch problem. If the requirements (however bad they may be) don't allow splitting the discretes out via more than one switch, does it buy me anything to go with a double- (or multi-) pole switch to run the wires through different contacts? Have you ever seen a multi-pole switch (toggle, PBA, or othewise) fail in such a way that only one set of contacts fails closed? Thanks, --Mark Navratil Cedar Rapids, Iowa RV-8A in painting hell... The best thing to hit the internet in years - Juno SpeedBand! Surf the web up to FIVE TIMES FASTER! ________________________________ Message 14 ____________________________________ Time: 04:19:23 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: expanded scale voltmeter and loadmeter --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:46 PM 9/3/2003 -0700, you wrote: >--> AeroElectric-List message posted by: Sigma Eta Aero > >Is the expanded scale voltmeter/loadmeter still being offered in kit or >finished form and if so how can I get one? No, I wasn't happy with the quality of the basic instrument. It was custom made for me but out of 30 pieces total, I had to have 3 units re-worked . . . some more than once. 10% failure rate is just too high. I'm considering an alternative device that should be less expensive and all solid state (bar graph) . . . but it's going to be awhile. Bob . . . ________________________________ Message 15 ____________________________________ Time: 04:33:20 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: double-pole switch failure modes --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:26 PM 9/3/2003 +0000, you wrote: >--> AeroElectric-List message posted by: czechsix@juno.com > > >Bob, > >In your experience, is there much value in replacing a single pole switch >with a double-pole switch in terms of separating signals where you want to >reduce exposure to single point failure? To elaborate a bit, the >situation I'm considering involves running ground/open discretes from >several pieces of equipment through a single switch in the cockpit that >shuts all equipment down when actuated. The obvious concern is that >there's a single-point failure mode where if the switch or any of the >wires connected to it fails by shorting to ground, the whole system goes >down. The wiring can be mostly isolated from this failure mode with >diodes but this still leaves the single switch problem. If the >requirements (however bad they may be) don't allow splitting the discretes >out via more than one switch, does it buy me anything to go with a double- >(or multi-) pole switch to run the wires through different contacts? Have >you ever seen a multi-pole switch (toggle, PBA, or othewise) fail in such >a way that only one set of contacts fails closed? obviously, one can load a set of contacts such that one pole of a multi-pole is compromised. Mechanical failure is pretty rare . . . but it sounds like you're dealing with low current levels . . . problem here is making sure you use a switch rated for dry-circuit applications. Many power handling switches depend on arcing to keep contact resistance low. How about a multi-pole, sealed relay, one pole per system for the disconnect function . . . then operate the relay with a push-button. If the button is not a dry-circuit device (gold plated contacts) then you can parallel the relay coil with a 12 ohm, 5w resistor (push button ops are short and wouldn't smoke the resistor). Or consider a ground-to-disable discrete that is pulled down with a hall effect device actuated by a push-button that moves a magnet in the appropriate way. This lets you wire-or all the disconnect lines together. Loss of pathway for any single discrete only affects your ability to shut down the one system. Bob . . . ________________________________ Message 16 ____________________________________ Time: 04:48:42 PM PST US From: Neil Clayton Subject: Re: AeroElectric-List: site back up . . . --> AeroElectric-List message posted by: Neil Clayton Bob....the data on your web site is SO valuable, that I for one would be happy to volunteer an annual contribution to retain it. I'm sure others would feel the same way. Neil At 04:36 PM 9/3/03, you wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > >We got the oil changed, refilled the tank and jumpstarted >the server . . . it's back up an running. > >While looking over the download traffic records, I noticed >that access to some of the big reference documents and >the CD Rom have expanded dramatically over the last two >months . . . and I am pleased that so many folks are >finding the data useful. > >Problem is that total traffic coming off our server >is setting new records both for bytes transferred -and- >co-location billing charges. I need to rethink how >much stuff I'm going to support there, particularly >in terms of things that one can find out there in >the wild on the 'net. My server bill for last month >was about 2x what it cost me with the last hosting >service . . . the whole idea of owning our own >server was to cut costs by more than half! > >At the moment, I think I'll have to back off on the >number and size of download options and go back to >offering the whole collection on an orderable CD. > >So, if anyone finds that a link to a previously >available item doesn't work, the reason is that the >item was pulled off the server. I'll be looking >for a way to bring this service back . . . > > > Bob . . . > > -------------------------------------------- > ( Knowing about a thing is different than ) > ( understanding it. One can know a lot ) > ( and still understand nothing. ) > ( C.F. Kettering ) > -------------------------------------------- > > ________________________________ Message 17 ____________________________________ Time: 07:07:59 PM PST US From: Kevin Horton Subject: Re: AeroElectric-List: site back up . . . --> AeroElectric-List message posted by: Kevin Horton I would also shell out a few shekels, but what would be really nice would be for someone to offer up some server space. Some one on this list must be a sys admin who could slip a few items onto his server without anyone complaining about it. Kevin Horton >--> AeroElectric-List message posted by: Neil Clayton > >Bob....the data on your web site is SO valuable, that I for one would be >happy to volunteer an annual contribution to retain it. >I'm sure others would feel the same way. > >Neil > > >At 04:36 PM 9/3/03, you wrote: >>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >> >> >>We got the oil changed, refilled the tank and jumpstarted >>the server . . . it's back up an running. >> >>While looking over the download traffic records, I noticed >>that access to some of the big reference documents and >>the CD Rom have expanded dramatically over the last two >>months . . . and I am pleased that so many folks are >>finding the data useful. >> >>Problem is that total traffic coming off our server >>is setting new records both for bytes transferred -and- >>co-location billing charges. I need to rethink how >>much stuff I'm going to support there, particularly >>in terms of things that one can find out there in >>the wild on the 'net. My server bill for last month >>was about 2x what it cost me with the last hosting >>service . . . the whole idea of owning our own >>server was to cut costs by more than half! >> >>At the moment, I think I'll have to back off on the >>number and size of download options and go back to >>offering the whole collection on an orderable CD. >> >>So, if anyone finds that a link to a previously >>available item doesn't work, the reason is that the >>item was pulled off the server. I'll be looking >>for a way to bring this service back . . . >> >> > > Bob . . . ________________________________ Message 18 ____________________________________ Time: 08:02:34 PM PST US From: "Ken Simmons" Subject: Re: AeroElectric-List: site back up . . . --> AeroElectric-List message posted by: "Ken Simmons" Bob, I could probably be persuaded to do this. We usually have 6-10 Mbps on our main website during the day. I think we could handle the traffic that you're seeing. I'm already hosting (and authoring) one EAA chapter's website and have offered space to another one. If you're interested, let me know. Ken ---------- Original Message ---------------------------------- From: Kevin Horton >--> AeroElectric-List message posted by: Kevin Horton > >I would also shell out a few shekels, but what would be really nice >would be for someone to offer up some server space. Some one on this >list must be a sys admin who could slip a few items onto his server >without anyone complaining about it. > >Kevin Horton > >>--> AeroElectric-List message posted by: Neil Clayton >> >>Bob....the data on your web site is SO valuable, that I for one would be >>happy to volunteer an annual contribution to retain it. >>I'm sure others would feel the same way. >> >>Neil >> >> >>At 04:36 PM 9/3/03, you wrote: >>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >>> >>> >>>We got the oil changed, refilled the tank and jumpstarted >>>the server . . . it's back up an running. >>> >>>While looking over the download traffic records, I noticed >>>that access to some of the big reference documents and >>>the CD Rom have expanded dramatically over the last two >>>months . . . and I am pleased that so many folks are >>>finding the data useful. >>> >>>Problem is that total traffic coming off our server >>>is setting new records both for bytes transferred -and- >>>co-location billing charges. I need to rethink how >>>much stuff I'm going to support there, particularly >>>in terms of things that one can find out there in >>>the wild on the 'net. My server bill for last month >>>was about 2x what it cost me with the last hosting >>>service . . . the whole idea of owning our own >>>server was to cut costs by more than half! >>> >>>At the moment, I think I'll have to back off on the >>>number and size of download options and go back to >>>offering the whole collection on an orderable CD. >>> >>>So, if anyone finds that a link to a previously >>>available item doesn't work, the reason is that the >>>item was pulled off the server. I'll be looking >>>for a way to bring this service back . . . >>> >>> >> > Bob . . . > > The Internet Truckstop The first and largest freight matching service on the Intenet ______________ ______________ ______________ ______________ Sent via the KillerWebMail system at truckstop.com ________________________________ Message 19 ____________________________________ Time: 09:29:15 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: site back up . . . --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:11 PM 9/3/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Ken Simmons" > >Bob, > >I could probably be persuaded to do this. We usually have 6-10 Mbps on our >main website during the day. I think we could handle the traffic that >you're seeing. I'm already hosting (and authoring) one EAA chapter's >website and have offered space to another one. > >If you're interested, let me know. > >Ken That would certainly be attractive as an interim if not long term solution. If I had access to some file space with an IP address to store the fat files, I could simply link to that space from my index pages. The stuff I took off the server today totals about 0.5 Gig and it's been growing steadily . . . Bob . . . ________________________________ Message 20 ____________________________________ Time: 10:46:02 PM PST US From: "Amit Dagan" Subject: AeroElectric-List: Internally regulated alternator --> AeroElectric-List message posted by: "Amit Dagan" Bob, I have been carefully studying your internally regulated alternator protection diagram (Z-24), and after I incorporate it into Z-11, I think I see no less than 5 (albeit related) protections against a malfunctioning alternator. If I have it right, I see: 1. 22AWG fusible link 2. 5A circuit breaker, connected to 3. Over-Voltage "corwbar" module 4. O-V disconnect relay 5. ANL60 current limiter. I wonder of you could explane the scenario in which each of these devices is called into action. And then I have 2 other questions: What could an automotive voltage regulator (if added to the circuit) give as far as protection ? If one has this regulator, Could one then eliminate any other devices ? Thanks, Amit. ________________________________ Message 21 ____________________________________ Time: 11:43:48 PM PST US From: John R Subject: Re: AeroElectric-List: expanded scale voltmeter and loadmeter --> AeroElectric-List message posted by: John R Why can't you just do a simple zener voltage dropping circuit? Yes it would be slightly non-linear, but close enough to serve very effectively, I should think - like: Ground ---> A <--10v Zener---> B <--- 1K-Ohm ----> C <--- Bus+ The bus voltage goes across points A and C; a 5-volt voltmeter goes across the 1K resistor (B and C)... if you want to use a direct-reading milliammeter (Full-Scale=1mA) rather than a voltmeter, just put a 5K resistor together in series with the milliammeter across points B and C above - or if you want to be able to calibrate it, use a 4.7K and 500-ohm trimpot instead of the 5K.If you're using a 50-uA meter, use a 100K resistor (or 90K + 20K trimpot) in series with the microammeter across points B and C. Wouldn't this be a lot simpler and get the job done? -John R. P.S.: If you want to go all solid state with a bargraph, a fairly simple circuit can be made around the LM3914 - as a matter of fact I believe I still have a hundred or so left over from a PC power supply monitor I used to manufacture - if you want to design a kit around it, I'll donate them to the cause (and yes they're still in their tubes)... Robert L. Nuckolls, III wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >At 12:46 PM 9/3/2003 -0700, you wrote: > > >>--> AeroElectric-List message posted by: Sigma Eta Aero >> >>Is the expanded scale voltmeter/loadmeter still being offered in kit or >>finished form and if so how can I get one? >> >> > > No, I wasn't happy with the quality of the basic instrument. > It was custom made for me but out of 30 pieces total, I had > to have 3 units re-worked . . . some more than once. 10% > failure rate is just too high. > > I'm considering an alternative device that should be less > expensive and all solid state (bar graph) . . . but it's > going to be awhile. > > Bob . . . > > > >