---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 08/21/05: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:08 AM - Re: NSI New Chief Engineer (Chuck Jensen) 2. 04:51 AM - Re: Wiring an RV-4 (Robert L. Nuckolls, III) 3. 05:13 AM - Re: recharge/jump start recepticle (Robert L. Nuckolls, III) 4. 07:30 AM - Re: NSI New Chief Engineer (Eric M. Jones) 5. 08:16 AM - Re: Re: Final (REALLY) PMag Update - Part 2 () 6. 08:36 AM - Re: Re: Final (REALLY) PMag Update - Part 2 (BobsV35B@aol.com) 7. 08:40 AM - Re: recharge/jump start recepticle (John Schroeder) 8. 08:46 AM - AMP connector pin source () 9. 08:47 AM - Re: Re: Final (REALLY) PMag Update - Part 2 (sportav8r@aol.com) 10. 09:41 AM - Re: AMP connector pin source (rv-9a-online) 11. 10:16 AM - Re: AMP connector pin source (gert) 12. 11:06 AM - Battery In Tail Questions (Sean Stephens) 13. 11:40 AM - Re: recharge/jump start recepticle (courierboy@earthlink.net) 14. 01:39 PM - Re: recharge/jump start recepticle (luckymacy@comcast.net (lucky)) 15. 04:55 PM - IR Alternator OVP (speedy11@aol.com) 16. 05:40 PM - Re: IR Alternator OVP (Paul Messinger) 17. 05:40 PM - Re: IR Alternator OVP (Charlie England) 18. 09:23 PM - Re: Antenna Cable Connector Source (rv-9a-online) ________________________________ Message 1 _____________________________________ Time: 03:08:41 AM PST US Subject: RE: AeroElectric-List: NSI New Chief Engineer From: "Chuck Jensen" --> AeroElectric-List message posted by: "Chuck Jensen" I'm taken aback.....waaaaaay back. Ah, does this mean Paul will be so busy in his new job that he won't have time to post to the Connection? Oh, the Humanity of it. Chuck Do Not Archive. -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric M. Jones Subject: AeroElectric-List: NSI New Chief Engineer --> AeroElectric-List message posted by: "Eric M. Jones" Hey AeroElectric Listers, NSI Aero in Arlington, Washington has been having some organizational problems recently. I am pleased to pass on the information that LeGrand Harris, the new General Manager, has asked Paul Messinger to be the new chief engineer. Paul says, "There is a huge task ahead and my first task is to do an engineering analysis of the current mechanical and electrical designs and document concerns and provide engineering updates, as required, both as a quick fix and a long term fix as required. Documentation needs to be updated and operations and limitations need to be written etc." Let's all wish Paul the very best of luck in this exciting challenge. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 (508) 764-2072 (do not archive) Don't worry about people stealing an idea. If it's original, you will have to ram it down their throats." -- Howard Aiken ________________________________ Message 2 _____________________________________ Time: 04:51:48 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Wiring an RV-4 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:31 PM 8/20/2005 -0700, you wrote: >--> AeroElectric-List message posted by: Ron Patterson > >Hello AeroElectric subscribers, > >I'm about to begin the wiring for my RV-4. Considered BMA's printed circut >board and PTC switch idea, but decided that was too expensive for my 12 >circuits (about $2K). That's interesting. I didn't know he had actually put a price on it and was offering it for sale. Of course we also don't know what all was in the "kit" but $2.000 is a real stretch given what others supply in their pre-wired, switch panel products for less than half that. More importantly, the product as last illustrated in http://www.aeroelectric.com/articles/richter/response_1.pdf was a long way from being a production offering as it was plagued with many electrical and mechanical issues. > Have ordered a Blue Sea 5026 fuse block ($40) and will use Bob's concept > of fly now, fix on the ground! > >I have the following for the panel: > >Dynon D10A >MicroAir T2000 transponder >XCOM Radio with built-in intercom >Flightcom i300 >Pictorial Pilot wing leveler >Altrak altitude hold >GRT EIS >Narco 122D VOR/GS with marker beacon >Garmin 296 >***Considering digital altimeter with encoder vs Dynons encoder or AK 350*** > >I have cables and pro-hub from Approach Systems for the XCOM, Transponder >and Narco. > >My question is what do I do to wire up the stick-grip push buttons? (PTT, >Autopilot, starter, electric fuel pump, radio frequency change)... how >many can go straight to a fuse, vs being regulated before going to the device? It's not necessary for ANY of the stick-grip wires to carry supply current. Given the small size of stick grip switches and wires, it's better to have the stick grip control the accessory system by GROUNDING. Current flowing in the stick grip switches should be in the 100mA to 1A range. Unless the accessory system can be directly controlled by grounding (like xmit PTT) then some form of control relays are called for like the relay decks offered by many for things like trim servos. >The Blue Sea has 12 return ground terminals. Should I use these or run a >seperate ground block? This will probably not be enough. Have you read the grounding chapter in the 'Connection Also check out the avionics/panel grounding concept in chapter 18. Bob . . . ________________________________ Message 3 _____________________________________ Time: 05:13:37 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: recharge/jump start recepticle --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:42 PM 8/20/2005 -0400, you wrote: >--> AeroElectric-List message posted by: Richard Dudley > >Hi Chris, >See Aeroelectric Connection by Bob Nucolls. There is a paper that >describes an external connection compatible with many FBO's APUs that >you can build into your RV. That is what I built into my -6A and I use >it all the time when I want to run the avionics in the hangar. It would >serve for battery charging, etc. also. See http://aeroelectric.com/articles/grndpwr.pdf I'm told that Cole-Hersee now offers the same power jack with a threaded post so that the modification proposed in the article is not necessary. Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:30:46 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: NSI New Chief Engineer --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: D Wysong >Eric -What happened to Paul's effort with the ghost company (I don't recall >him ever parting with the name) to develop a "next generation aircraft >electrical system"... or something along those lines? Did he/they >shelve the design, scrap it, or is it now in his 'side work' pile? >Inquiring minds want to know (... well... mine does, anyway). >Pass along a congrats on the new gig! D The Ghost Company was NSI. (I would have paid money to see Paul and Lance Wheeler argue with each other.) The Next Generation electrical system is not first priority since NSI is in real trouble--"Bigger than you can imagine trouble." The Yahoo subie groups (http://groups.yahoo.com/group/E-SubieForum/) have more information. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 (508) 764-2072 Teamwork: " A lot of people doing exactly what I say." (Marketing exec., Citrix Corp.) ________________________________ Message 5 _____________________________________ Time: 08:16:21 AM PST US From: Subject: Re: AeroElectric-List: Re: Final (REALLY) PMag Update - Part 2 --> AeroElectric-List message posted by: Stormy, Your idyllic vision of the gear's life would be true, IF we were dealing with "constant combustion" (turbine or jet) engines. However, our Lycomings are 4 cylinder "intermittent combustion" engines. The gears need to be hardened to take the constant "jack hammering" they receive due to this process. This process is also what made both Lycoming and Continental quit making geared piston engines. Charlie Kuss ---- sportav8r@aol.com wrote: > --> AeroElectric-List message posted by: sportav8r@aol.com > > Though I have not spoken yet with anyone knowlegdgeable about this news, your answer agrees well with my initial impression: the gear is so lightly loaded in this application (turning an optical encoder wheel in the E-mag and also a light-duty, rarely-loaded alternator in the P-Mag) that accelerated wear seems mechanically impossible so long as alignment is correct. If alignment is off, it's anyone's guess how well the gear would fare, and you'd be glad the soft gear took the punishment. > > -Stormy > > -----Original Message----- > From: Chris & Kellie Hand > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Re: Final (REALLY) PMag Update - Part 2 > > > --> AeroElectric-List message posted by: "Chris & Kellie Hand" > > > My RV-6A engine should be ready for me sometime this fall, ordered with an > e-mag/p-mag combination so this thread definitely caught my attention. I > asked them about it, and they have the following posted on the Innovation > section of their web site (http://www.emagair.com/Innovation.htm) : > > Q: I read about an occurrence of excessive drive gear wear and your gears > not being certified. Can you elaborate? > > A: As stated on order forms and price lists, our drive gears are not > certified gears. We try to replicate certified gears in terms of both their > dimension and their hardness. It was surprising to us (at first) to find > the certified gear we had tested was not hardened. We then realized there > would be advantages in keeping the drive gear (accessible and easy to > replace) unhardened so it will wear before the gear it engages (inside the > engine and much harder to inspect/replace). Of the numerous in-service > gears that have come through our shop, we've seen only one (1) occurrence of > significant wear/deformation of a drive gear. In all likelihood it was > caused by some kind of foreign matter under one side of the flange when it > was clamped down. That would have cocked the unit to one side, preload the > gear, and cause the excessive wear. > > > They also said you do have the option of using a certified gear if desired, > as I think somebody else pointed out in an earlier reply. > > I don't know enough about mag drive gears to know whether certified gears > are or are not hardened, or whether they should be, but am posting this as > additional info on the subject and it sounds like emagair has checked on > that question. > > Chris Hand > RV-6A, finishing kit stage > > > >Subject: FW: [c-a] Final (REALLY) PMag Update - Part 2 > > >From: "RV Builder (Michael Sausen)" > > > > > >Subject: [c-a] Final (REALLY) PMag Update - Part 2 > > > > > >I would suggest, however, that anyone with an Emag or Pmag on their > running engine > > >remove them to examine the gear for wear/damage. Maybe my gear was > an anomaly > > >- god knows that I seem to have more than my fair share of them, > but if there > > >was a bad run of gears, folks should check to make sure that > they're not > > >making metal in their engines, too. Try to file a tip of one gear > tooth - if > > >the file takes off metal, it's not hardened. Check with YOUR > engine experts to > > >see if they concur that it SHOULD be hardened - that's what Ken and > his two > > >guys said. > > > > > >Marc J. Zeitlin > > > > > > --------------------------------- > > > > > > > > > > ________________________________ Message 6 _____________________________________ Time: 08:36:24 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Re: Final (REALLY) PMag Update - Part 2 --> AeroElectric-List message posted by: BobsV35B@aol.com Good Morning Charlie, I know this is way out of any field of expertise that I may have, but I wonder if we may not be discussing apples and oranges here? It would seem to me that those gears in the back of the engine would encounter much lower stresses than those used to gear down a propellor shaft. As the gear only needs to deliver a timing function, I would think that a gear that had been designed to drive a magneto would have a lot more strength than is required to drive the timing device needed by the E or P mag unit. Reduction gearing on the older Lycomings has proven very reliable. So much so that most engines of that era are overhauled often with nothing being done to the reduction gears other than careful inspection. The multi-cylinder radials that powered our piston airline fleets attained amazingly long gear lives even though they were under very high stresses. Admittedly, the power pulses came a lot closer together on eighteen cylinder engines than they do on a four banger, but it does seem that those back of the engine gears should not have to be terribly sophisticated entities. Happy Skies, Old Bob In a message dated 8/21/2005 10:17:28 AM Central Standard Time, chaztuna@adelphia.net writes: Stormy, Your idyllic vision of the gear's life would be true, IF we were dealing with "constant combustion" (turbine or jet) engines. However, our Lycomings are 4 cylinder "intermittent combustion" engines. The gears need to be hardened to take the constant "jack hammering" they receive due to this process. This process is also what made both Lycoming and Continental quit making geared piston engines. Charlie Kuss ________________________________ Message 7 _____________________________________ Time: 08:40:46 AM PST US Subject: Re: AeroElectric-List: recharge/jump start recepticle From: "John Schroeder" --> AeroElectric-List message posted by: "John Schroeder" Bob - We installed your ground power system in addition to the Z-14 in our Lancair ES. I bought a small power supply on eBay that you had recommended (12V nominal that had been set to 13.5V by the seller). We use it all the time to check out the electrical system and instrumentation. Great setup. Works great. I would like to use the external power receptacle to plug in a battery charger/maintainer. It should work well to charge/maintain the #1 battery when just the ground power switch/cb is on and the contactor is closed. This means we give up .8 amp off the top of the charger's capacity. However, the problem comes when we want to charge/maintain the #2 battery. By using the external power jack, we have to have all four of the contactors closed - giving up 3.2 amps. The entire electrical system of the aircraft would be hot while the batteries charge. We then worry about one battery being over charged if the other one is lower. Any tender/maintainer will stay on the charge cycle until it senses the lowest battery at the peak charge before going to the maintain mode. Correct? Question: Is it a good idea to use the ground power system to charge and maintain the batteries? If so, can you recommend a maintainer and a circuit change that can do the job? Or, would it be better to just add 4 more wires and a couple of plugs to the batteries and use two of the smaller tenders? Many thanks, John Schroeder Lancair ES 85% On Sun, 21 Aug 2005 07:06:51 -0500, Robert L. Nuckolls, III wrote: > See http://aeroelectric.com/articles/grndpwr.pdf > I'm told that Cole-Hersee now offers the same power jack > with a threaded post so that the modification proposed > in the article is not necessary. -- ________________________________ Message 8 _____________________________________ Time: 08:46:30 AM PST US From: Subject: AeroElectric-List: AMP connector pin source --> AeroElectric-List message posted by: AeroElectric-List message previously posted by: Mickey Coggins <> 8/21/2005 Hello Mickey, I think you may be mixing up Molex and AMP pins and connectors. Just make sure that you are using the pins and plastic connector shells from the same manufacturer. If you are sure that your plastic shells are AMP Mate N Lok brand then you can get compatible pins from Terminal Town http://www.terminaltown.com/ Pay very close attention to part numbers. OC ________________________________ Message 9 _____________________________________ Time: 08:47:03 AM PST US From: sportav8r@aol.com Subject: Re: AeroElectric-List: Re: Final (REALLY) PMag Update - Part 2 --> AeroElectric-List message posted by: sportav8r@aol.com Idyllic or not, we'll all have to wait and see what the longer term field experience is with these gears. For me, the most relevant point is that made by Brad, who states the Lycoming gears they were copying were also not case-hardened. If that's correct, we're probably looking at an isolated failure here. Time will tell. -Stormy -----Original Message----- From: chaztuna@adelphia.net Subject: Re: AeroElectric-List: Re: Final (REALLY) PMag Update - Part 2 --> AeroElectric-List message posted by: Stormy, Your idyllic vision of the gear's life would be true, IF we were dealing with "constant combustion" (turbine or jet) engines. However, our Lycomings are 4 cylinder "intermittent combustion" engines. The gears need to be hardened to take the constant "jack hammering" they receive due to this process. This process is also what made both Lycoming and Continental quit making geared piston engines. Charlie Kuss ________________________________ Message 10 ____________________________________ Time: 09:41:09 AM PST US From: rv-9a-online Subject: Re: AeroElectric-List: AMP connector pin source --> AeroElectric-List message posted by: rv-9a-online Amp commercial Mate-N-Lock connectors. Here are the Digi-key part numbers. A1400-ND CONN RECEPT/CAP 3 POS MATE-N-LOK A1429-ND CONN PLUG 3POS MATE-N-LOK A1422-ND CONN PIN 18-24AWG TIN CRIMP A1423-ND CONN SOCKET 18-24AWG TIN CRIMP I also used 2-pin and 4-pin versions of these (4-pin is good for strobe wing root disconnect). Vern Little RV-9A bakerocb@cox.net wrote: >--> AeroElectric-List message posted by: > >AeroElectric-List message previously posted by: Mickey Coggins > > ><AMP pins that go into a strobe AMP connector. > >I'm sure someplace like Digikey has them, but >I can't find them on their website. > >What I'm looking for is just the pins on >this page:......skip........ > >Thanks for any hints, or part numbers, or official >unique names! Mickey Coggins>> > >8/21/2005 > >Hello Mickey, I think you may be mixing up Molex and AMP pins and >connectors. Just make sure that you are using the pins and plastic connector >shells from the same manufacturer. > >If you are sure that your plastic shells are AMP Mate N Lok brand then you >can get compatible pins from Terminal Town http://www.terminaltown.com/ > >Pay very close attention to part numbers. > >OC > > > > ________________________________ Message 11 ____________________________________ Time: 10:16:11 AM PST US From: gert Subject: Re: AeroElectric-List: AMP connector pin source --> AeroElectric-List message posted by: gert there is a difference between regular Mate-N-Lock and *Commercial* Mate-N-Lock. the strobes had the Commercial variety of Mate-n-Lock connectors, once I figured that out getting additional items was easy. I believe SteinAir sells the regular Mate-N-Lock, I know, I bought some of his 2, for a different purpose. bakerocb@cox.net wrote: >--> AeroElectric-List message posted by: > >AeroElectric-List message previously posted by: Mickey Coggins > > ><AMP pins that go into a strobe AMP connector. > >I'm sure someplace like Digikey has them, but >I can't find them on their website. > >What I'm looking for is just the pins on >this page:......skip........ > >Thanks for any hints, or part numbers, or official >unique names! Mickey Coggins>> > >8/21/2005 > >Hello Mickey, I think you may be mixing up Molex and AMP pins and >connectors. Just make sure that you are using the pins and plastic connector >shells from the same manufacturer. > >If you are sure that your plastic shells are AMP Mate N Lok brand then you >can get compatible pins from Terminal Town http://www.terminaltown.com/ > >Pay very close attention to part numbers. > >OC > > > > -- is subject to a download and archival fee in the amount of $500 ________________________________ Message 12 ____________________________________ Time: 11:06:41 AM PST US From: Sean Stephens Subject: AeroElectric-List: Battery In Tail Questions --> AeroElectric-List message posted by: Sean Stephens First off, I'd like to make the statement that I am a "noob" when it comes to some of these things, but I am slowly putting things together after reading The Connection and lurking here. So be gentle if I use some incorrect "terminology". :) I will most likely have some form of Z-13. At this point most likely a Z-13/Z-30 derivative. The dual bats will be in the tail. I believe that a good place to establish the main power distribution bus connection is to connect from the starter contactor. Maybe an ANL between? Is that correct? My biggest sticking point is with the bat bus and aux bat bus being in the tail. The feeds to the bat/aux bat bus items along with the e-bus alt feed will have to run the length of the fuse. I read in The Connection that it is wise to run all these wires along one side of the plane (Page-7 Note 5)? Is it ok to have all the large and small wires routed together in one conduit? Are there other issues I have to be concerned with? Maybe I'm just making too big a deal out of it and as long as my fuses and wires are properly sized, the battery buses being located in the tail will be just fine? I guess I just need confirmation that I'm on the right track and maybe a few "gotchas" that I need to look out for. Thanks All... -Sean RV-10 #40303 http://rv10.stephensville.com ________________________________ Message 13 ____________________________________ Time: 11:40:55 AM PST US From: courierboy@earthlink.net Subject: Re: AeroElectric-List: recharge/jump start recepticle --> AeroElectric-List message posted by: courierboy@earthlink.net >--> AeroElectric-List message posted by: "chris macy" > >Hi, >I'm looking for a way to be able to recharge or jumpstart my battery >from outside the plane which is in the back of an RV8. > >What I have in mind is a receptacle which is flush with the bottom >of the fuse and has a rubber plug to seal it while not in use. I >want the wire sized to be able to handle the current of a jump start >and bolted to the battery just like the start/ground cables are. I >am not aware I've seen something like this before except for a >bigger version like an APU jack in military aircraft but that's >overkill for an RV. But I thought I heard it discussed in past >years on the list but my archive search didn't turn up anything. I >was hoping West Marine would have something similar but I didn't >find anything. > >Any ideas? > >thx, >lucky lucky - This is not exactly what you describe but worth looking at: http://solanopilots.com/quickjumpsolution.htm Find more ideas at the AEC web site at "How to Articles" under "Downloadable Reference Materials". Click on "Low Cost Ground Power Jack for Your Airplane" Bill ________________________________ Message 14 ____________________________________ Time: 01:39:53 PM PST US From: luckymacy@comcast.net (lucky) Subject: Re: AeroElectric-List: recharge/jump start recepticle --> AeroElectric-List message posted by: luckymacy@comcast.net (lucky) Thanks for all the responses. I ordered the Piper receptical and plug from ACS. It's just what I was looking for and the link below confirmed it. I think it can easily work for both a battery tender and jump starter. Lucky -------------- Original message -------------- > --> AeroElectric-List message posted by: courierboy@earthlink.net > > >--> AeroElectric-List message posted by: "chris macy" > > > >Hi, > >I'm looking for a way to be able to recharge or jumpstart my battery > >from outside the plane which is in the back of an RV8. > > > >What I have in mind is a receptacle which is flush with the bottom > >of the fuse and has a rubber plug to seal it while not in use. I > >want the wire sized to be able to handle the current of a jump start > >and bolted to the battery just like the start/ground cables are. I > >am not aware I've seen something like this before except for a > >bigger version like an APU jack in military aircraft but that's > >overkill for an RV. But I thought I heard it discussed in past > >years on the list but my archive search didn't turn up anything. I > >was hoping West Marine would have something similar but I didn't > >find anything. > > > >Any ideas? > > > >thx, > >lucky > > > lucky - > > This is not exactly what you describe but worth looking at: > http://solanopilots.com/quickjumpsolution.htm > > Find more ideas at the AEC web site at "How to Articles" under > "Downloadable Reference Materials". Click on "Low Cost Ground Power > Jack for Your Airplane" > > Bill > > > > > > Thanks for all the responses. I ordered the Piper receptical and plug from ACS. It's just what I waslooking for and the link below confirmed it. I think it can easily work for both a battery tender and jump starter. Lucky -------------- Original message -------------- -- AeroElectric-List message posted by: courierboy@earthlink.net -- AeroElectric-List message posted by: "chris macy" Hi, I'm looking for a way to be able to recharge or jumpstart my battery from outside the plane which is in the back of an RV8. What I have in mind is a receptacle which is flush with the bottom of the fuse and has a rubber plug to seal it while not in use. I want the wire sized to be able to handle the current of a jump start and bolted to the battery just like the start/ground cables are. I am not aware I've seen something like this before except for a bigger version like an APU jack in military aircraft but that's
overkill for an RV. But I thought I heard it discussed in past years on the list but my archive search didn't turn up anything. I was hoping West Marine would have something similar but I didn't find anything. Any ideas? thx, lucky lucky - This is not exactly what you describe but worth looking at: http://solanopilots.com/quickjumpsolution.htm Find more ideas at the AEC web site at "How to Articles" under "Downloadable Reference Materials". Click on "Low Cost Ground Power Jack for Your Airplane" Bill criptions page, ________________________________ Message 15 ____________________________________ Time: 04:55:02 PM PST US From: speedy11@aol.com Subject: AeroElectric-List: IR Alternator OVP --> AeroElectric-List message posted by: speedy11@aol.com Suppose one installed an internally regulated alternator and wanted overvoltage protection. Suppose the alternator has a B lead to power the bus, a S lead to sense voltage on the bus and adjust the alternator output, and a "G" lead for grounding. Question 1 - would breaking the ground wire cause the alternator to quit? Question 2 - If so, then could one have a sensor on the B lead that, during an overvoltage, would command a contactor in the ground wire to open and thus shut down the alternator? Question 3 - Could said contactor be a solid state relay instead? Ready for the flames. Stan Sutterfield RV-8A ________________________________ Message 16 ____________________________________ Time: 05:40:53 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: IR Alternator OVP --> AeroElectric-List message posted by: "Paul Messinger" The common alternators are not wired that way. There is a I lead that is alternator control when it is working properly and opening and closing the I lead turns on and off the output power coming from the "B" terminal. The L terminal is part of the so called IDIOT light in autos and really only a ground lead for a light. Some also have a S lead for remote voltage sensing so voltage drop from the B lead to the battery can be allowed for. The ground is the alternator case and not something to be controlled. The problem with internally regulated alternators is IF (extremely rare) the internal power transistor in the internal field lead shorts there is no way to remove field power and the B lead will become a constant current source and the 55 amp alternator will try to provide 70 or more amps. The B lead voltage will quickly rise until the system bus absorbs 70 amps. The battery (once fully charged) will not clamp the voltage and in many cases the voltage rises from 14v to over 24 volts at around 1/2 volt per second and can end up over 30 volts if that is what is needed to load the alternator. Its true the 70 amps will decrease as the voltage rises but in the interim your electrical system is subject to massive failure from overvoltage if nothing is done. The OVP designs floating around including aeroelectric list have demonstrated on Vans aircraft to apparently create alternator failures. The problem may be the contactor used and the common contactor is not designed for and will NOT work reliably in this application. Only a contactor designed for this application will work and one device is the Kilovac unit that is rated for the very high arcing voltages present. The redesigned NSI system will have a reliable OV protection option. Lots more later but you are much more likely to have an engine failure than an alternator High voltage output failure. Current solid state technology is not cost effective (for the B lead circuit) but costs are dropping. Paul PS I have thrown my flamethrower in the trash given my new position at NSI. There are no dumb questions just dumb replys. An educated pilot is a safer pilot. ----- Original Message ----- From: Subject: AeroElectric-List: IR Alternator OVP > --> AeroElectric-List message posted by: speedy11@aol.com > > > Suppose one installed an internally regulated alternator and wanted > overvoltage protection. > Suppose the alternator has a B lead to power the bus, a S lead to sense > voltage on the bus and adjust the alternator output, and a "G" lead for > grounding. > Question 1 - would breaking the ground wire cause the alternator to quit? > Question 2 - If so, then could one have a sensor on the B lead that, > during an overvoltage, would command a contactor in the ground wire to > open and thus shut down the alternator? > Question 3 - Could said contactor be a solid state relay instead? > Ready for the flames. > Stan Sutterfield > RV-8A > > > ________________________________ Message 17 ____________________________________ Time: 05:40:53 PM PST US From: Charlie England Subject: Re: AeroElectric-List: IR Alternator OVP --> AeroElectric-List message posted by: Charlie England speedy11@aol.com wrote: >--> AeroElectric-List message posted by: speedy11@aol.com > > > Suppose one installed an internally regulated alternator and wanted overvoltage protection. >Suppose the alternator has a B lead to power the bus, a S lead to sense voltage on the bus and adjust the alternator output, and a "G" lead for grounding. >Question 1 - would breaking the ground wire cause the alternator to quit? >Question 2 - If so, then could one have a sensor on the B lead that, during an overvoltage, would command a contactor in the ground wire to open and thus shut down the alternator? >Question 3 - Could said contactor be a solid state relay instead? >Ready for the flames. >Stan Sutterfield >RV-8A > It's likely that the case is common with the G terminal. You can check with an ohm meter. Even if it isn't, there would be no advantage to breaking the ground because the same current flows in the return path as the B+ path. As long as the solid state relay can handle the voltage & current, sure, it will work. (There are all kinds of subtle reasons why you can and/or can't do any of the above, but the experts would have to kill you if they explained it.) < obligatory :-) > Charlie ________________________________ Message 18 ____________________________________ Time: 09:23:32 PM PST US From: rv-9a-online Subject: Re: AeroElectric-List: Antenna Cable Connector Source --> AeroElectric-List message posted by: rv-9a-online Check with an avionics shop... this is only available from Garmin. It's a horrendous price, about $20.00. My avionics shop said to use the solder tail connector, then put an in-line BNC connector in the coax, which is what I did. Vern Little DAVID REEL wrote: >--> AeroElectric-List message posted by: "DAVID REEL" > >No luck in the archives. Does anyone have a source for the BNC type coaxial cable connector attached to the transponder tray with a snap ring on the Garmin GTX320A? My unit came with a solder type connector & I would like to have a BNC style connection to simplify panel removal. The Garmin part number is 330-00326-00. > >Dave Reel - RV8A > > > >