---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 01/22/05: 30 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:36 AM - Battery failure -- lessons and questions (Frank & Dorothy) 2. 04:02 AM - Re: Battery failure -- lessons and questions on dbmail-mx1 (KITFOXZ@aol.com) 3. 07:10 AM - Re: 11868 Linderman (Robert L. Nuckolls, III) 4. 07:17 AM - Re: Battery failure -- lessons and questions on dbm (earl_schroeder@juno.com) 5. 08:32 AM - Re: Rotary Switch- solution found (jerb) 6. 09:04 AM - Re: Battery failure -- lessons and questions (Robert McCallum) 7. 09:43 AM - Re: Z13a Pre-flight alt test procedure? (Mike Holland) 8. 11:29 AM - Re: Battery failure -- lessons and questions (Paul Messinger) 9. 11:29 AM - turning off an internally regulated alternator (Paul Messinger) 10. 12:49 PM - Re: turning off an internally regulated alternator (Alex Peterson) 11. 01:12 PM - Re: turning off an internally regulated alternator (Paul Messinger) 12. 01:16 PM - Re: turning off an internally regulated alternator (Ed Anderson) 13. 01:28 PM - Re: Re: Load dump comments (Vincent Welch) 14. 01:36 PM - Re: turning off an internally regulated alternator (Paul Messinger) 15. 01:36 PM - Re: turning off an internally regulated alternator (Alex Peterson) 16. 01:52 PM - Load Dump Question (Vincent Welch) 17. 02:00 PM - OVP current limiting (Paul Messinger) 18. 02:02 PM - Pilot stick grip priority options rev B (Mark Banus) 19. 02:30 PM - Re: Load Dump Question (Paul Messinger) 20. 02:30 PM - Re: turning off an internally regulated alternator (Paul Messinger) 21. 03:11 PM - Garmin/Microencoder wiring question (Dan O'Brien) 22. 03:23 PM - General radio grounding question (Dan O'Brien) 23. 04:03 PM - Re: Garmin/Microencoder wiring question (Wayne Sweet) 24. 04:06 PM - Re: General radio grounding question (Wayne Sweet) 25. 04:20 PM - Re: Load Dump Question (Robert L. Nuckolls, III) 26. 04:44 PM - Re: Load Dump Question (Vincent Welch) 27. 06:39 PM - Re: Garmin/Microencoder wiring question (Dan O'Brien) 28. 06:44 PM - Re: General Wiring Question (Dan O'Brien) 29. 07:04 PM - Re: Re: Garmin/Microencoder wiring question (Wayne Sweet) 30. 07:20 PM - Re: Re: General Wiring Question (Wayne Sweet) ________________________________ Message 1 _____________________________________ Time: 02:36:49 AM PST US From: Frank & Dorothy Subject: AeroElectric-List: Battery failure -- lessons and questions on dbmail-mx1 --> AeroElectric-List message posted by: Frank & Dorothy Hi, Thought you guys might benefit from my experience today with my car battery (at an air show, so it is aviation related :-) And there are some bits of what I think are aeroelectric technology information. Anyone not wanting to read my screeds should skip directly to LESSONS. I recently installed an engine immobiliser after my car disappeared overnight a couple of times (the plane project is in the garage). When the car wouldn't start a couple of times over the last month or two, I put it down to a not-too-well setup cheap immobiliser. When the car started after a couple of twiddles with the immobiliser wires, that confirmed it. Today though, at an airshow about 2 hours drive from home, it wouldn't crank again. :-( :-( Just a buzzing series of clicks from the immobiliser relay. Twiddled the wires. Still no go. Tried the electric windows -- they went down OK, but still no cranking. Disconnected the immobiliser entirely. No help. Hmmm... borrowed some jumper leads, and persuaded the guy on the next-door car in the parking lot to help out with his alternator and battery. No go. Turning the key resulted in the dash waring lights all going out. Now, this was really surprising. someone came along with a diesel-powered car with a *big* battery... STILL no go. By now, I'd decided that there was probably a fault in the starter motor or ring gear :-( The kibbitzers (when waiting in a queue to get out of an airfield carpark after a show, any entertainment is welcome) and the hassle of somehow getting home, and then coming back the next day or even 2 days later, it being a holiday on Monday) eventually persuaded me to try a new battery. I got a ride to the nearest gas station, bought a battery (at an exorbitant price) and borrowed a couple of spanners, and got back to the airfield and replaced the battery. Somewhat to my surprise, everything suddenly worked properly! As I see it now, when the starter motor isn't turning, its coils have less impedance/resistance than the rest of the circuitry in the car. Hence, turning the key to 'start' would drop the voltage across the warning lights so that they went out. But the battery couldn't provide enough oomph to turn the starter motor, so from the battery's point of view there was more or less a short circuit. I'm thinking that probably one (or more) of the battery's cells has died, so the battery couldn't provide 12.5V, and some reduced amount of current. (I kept the bad battery, and will investigate it with voltmeter, etc tomorrow) I still don't see why adding more oomph via external battery and jumper leads didn't get the car started. I guess that somehow the dead cell in the bad battery was providing some kind of low-resistance path for the juice from the good battery to flow through, instead of through the starter motor??? But there was no noticeable heating of the jumper leads, or loading down of the running car which I'd expect in that situation. Also, I'd expect (but didn't see) sparks when I attached the last jumper leads. Another question that I'm wondering about: How can putting jumper leads on a car blow its computer (as I was warned about today)? Surely, from the computer's point of view, it can't tell whether the flow of electricity its receiving is coming from the car's own battery, an external battery, or some combination of both? If 'surges of electricity' are the culprit as someone contended today, then surely disconnecting a near-dead battery and connecting a new fully-charged battery is worse than jumpering the full battery across the near-dead one? And what about the voltage transients when the alternator starts up? Is this "putting jumper leads on a car blow its computer" just a myth? BobN, I'd appreciate it if you would satisy my curiosity over the physics of what happened today. LESSONS: 1. When your battery suggests that it is about to die, take heed! 2. Somehow, a bad battery can prevent a parallel good battery from working! This may be especially relevant for people installing dual batteries in their aircraft -- if you can't isolate a bad battery, it may prevent starting (or even take down the electrical system???) even if you have a good battery (or perhaps even a running alternator???) alongside. Frank ________________________________ Message 2 _____________________________________ Time: 04:02:35 AM PST US From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: Battery failure -- lessons and questions on dbmail-mx1 --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 1/22/2005 5:38:12 A.M. Eastern Standard Time, frankv@infogen.net.nz writes: LESSONS: 1. When your battery suggests that it is about to die, take heed! 2. Somehow, a bad battery can prevent a parallel good battery from working! This may be especially relevant for people installing dual batteries in their aircraft -- if you can't isolate a bad battery, it may prevent starting (or even take down the electrical system???) even if you have a good battery (or perhaps even a running alternator???) alongside. Frank Hello Frank, Your lesson # 1 is so very true! This is one reason that Bob always preaches about replacing aircraft batteries on a regular interval. The battery is the most unpredictable component in your aircraft, and yet the most depended upon. An old battery can have a shorted cell, thus reducing the battery's voltage to 10 volts. A jumper battery connected in parallel across this bad 10 volt battery will often be unable to boost the system voltage enough to start your engine. This is why it is a good idea to remove the battery in question from the circuit, if a jump fails to get you going, and replace it with a known good battery. An old battery with a shorted cell will receive full charge current from the charging system too as the voltage regulator pushes tons of current into this bad battery trying to restore its voltage to 13.8. The excess charge current will destroy the other cells in a short time. I have never liked using an "immobilizer" type of device in any of my cars for fear that the thing would fail to "make" my starting circuit on a cold and rainy night. The shops that install them often use any number of poor connection practices as they install these bottom dollar devices. I prefer to not have my starting circuit compromised in any way. A simple noise maker alarm system is my choice. If the thief defeats the alarm or drives off with it screaming, I say let it be. Any electronic theft deterrent is just that in my opinion, a deterrent. The average thief is dumb and in a hurry for an easy victim. Sure there are the pros out there working for chop shops and those few guys will know how to start your car no matter what you have installed to foil them. John P. Marzluf Columbus, Ohio Kitfox Outback (out back in the garage) ________________________________ Message 3 _____________________________________ Time: 07:10:57 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: 11868 Linderman --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:24 AM 1/22/2005 +0000, you wrote: >Below is the result of your inquiry. It was submitted by >Lucas Linderman (linluc23@email.pct.edu) on Friday, January 21, 2005 at >20:24:58 > >Friday, January 21, 2005 > >Lucas Linderman > >, >Email: linluc23@email.pct.edu >Comments/Questions: Mr. Nuckolls, > My name is Luke Linderman and I am senior at the Pennsylvania College > of Technology in Williamsport Pennsylvania. I am enrolled in the Bachelor > of Aviation Maintenance with the first two years concentrating on the A&P > License and the last two on Avionics. As a requirement to graduate we > have to do an intensive senior project. For my project I am designing and > electrical system install in RV-7/7A. The homebuilder is currently > desiding on whether to go with Figure Z-12 or Z-13. I was just wondering > if those diagrams are just basic idea or if the wires are already set at > the right size? Electrical system architecture for light aircraft has not materially changed since the C-140 and C-170 got their first generators and batteries installed in the late 40s. The only real "bump up" in electrical system capabilities came in the late 60s when generators were replaced with alternators and the avionics master switch and bus were added for the wrong reasons. The Z-figures were crafted to offer some choices for system architecture allowing a builder to optimize performance, minimize parts count, and craft simple, failure tolerant operation tailored to an airplane's mission. NONE of the wire sizes, breaker/fuse sizes, or part numbers of components should be construed as recommended for any particular design. I would begin the design for a new aircraft by conducting a load analysis. There is a blank form you can download at: http://www.aeroelectric.com/articles/LoadAnalysis.pdf . . . one page for each bus of your selected architecture. List every electro-whizzie that draws power from the system and deduce its requirements under all the flight conditions noted across the top of the form. This exercise will help you size wires, circuit protection, batteries and alternators. > I thank you for your time and look forward to talking to you in the > future about this if possible. Please join us on the AeroElectric-List which is described at: http://aeroelectric.com/consulting.html This service is free and may be joined or abandoned at any time. Participation on this list will put you in contact with many capable builders/designers who share your interests. I would encourage you to pass this invitation along to your fellow students as well. As you look forward to your own career, please know that the best way to advance the state of your own art is to TEACH IT. The AeroElectric-List is a good place to acquire those skills by taking advantage of all that folks on the List are eager and willing to share. As your personal knowledge and skills grow, you will have much to offer others. When we take the time to share our particular stock of simple ideas and discuss the ways in which those ideas can be assembled into practical inventions, we ALL become teachers in the finest sense of the word. Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:17:32 AM PST US From: "earl_schroeder@juno.com" Subject: Re: AeroElectric-List: Battery failure -- lessons and questions on dbm ail-mx1 --> AeroElectric-List message posted by: "earl_schroeder@juno.com" In an attempt to squeeze out more life from an old car, I installed an 'aircraft approved master relay' which completely disconnects the battery as it does in aircraft. It solved the very intermittent battery draining situation which I was unable to find. A 'hidden' master switch also serves as an 'immobilizer' although if someone wants this old car... Now my digital clock serves as a time-in-route. Earl -- KITFOXZ@aol.com wrote: --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 1/22/2005 5:38:12 A.M. Eastern Standard Time, frankv@infogen.net.nz writes: LESSONS: 1. When your battery suggests that it is about to die, take heed! 2. Somehow, a bad battery can prevent a parallel good battery from working! This may be especially relevant for people installing dual batteries in their aircraft -- if you can't isolate a bad battery, it may prevent starting (or even take down the electrical system???) even if you have a good battery (or perhaps even a running alternator???) alongside. Frank Hello Frank, Your lesson # 1 is so very true! This is one reason that Bob always preaches about replacing aircraft batteries on a regular interval. The battery is the most unpredictable component in your aircraft, and yet the most depended upon. An old battery can have a shorted cell, thus reducing the battery's voltage to 10 volts. A jumper battery connected in parallel across this bad 10 volt battery will often be unable to boost the system voltage enough to start your engine. This is why it is a good idea to remove the battery in question from the circuit, if a jump fails to get you going, and replace it with a known good battery. An old battery with a shorted cell will receive full charge current from the charging system too as the voltage regulator pushes tons of current into this bad battery trying to restore its voltage to 13.8. The excess charge current will destroy the other cells in a short time. I have never liked using an "immobilizer" type of device in any of my cars for fear that the thing would fail to "make" my starting circuit on a cold and rainy night. The shops that install them often use any number of poor connection practices as they install these bottom dollar devices. I prefer to not have my starting circuit compromised in any way. A simple noise maker alarm system is my choice. If the thief defeats the alarm or drives off with it screaming, I say let it be. Any electronic theft deterrent is just that in my opinion, a deterrent. The average thief is dumb and in a hurry for an easy victim. Sure there are the pros out there working for chop shops and those few guys will know how to start your car no matter what you have installed to foil them. John P. Marzluf Columbus, Ohio Kitfox Outback (out back in the garage) ________________________________ Message 5 _____________________________________ Time: 08:32:15 AM PST US From: jerb Subject: Re: AeroElectric-List: Rotary Switch- solution found --> AeroElectric-List message posted by: jerb Question - is this switch, switching AC or DV voltages - switches rated for AC normally will only handle a fraction of their current rating when operated in a DC application. It has to do with the type of contacts used in each switch, DC switches cost more to make because of the material that has to be used to reduce arcing when contacts break and resist welding. AC switches take advantage of the zero point crossing of the AC swine wave to reducing arching effect when contact break thus allow the use of lower cost materials for the contacts. jerb At 10:22 PM 1/21/05 -0600, you wrote: >--> AeroElectric-List message posted by: Bonnie & August Lehmann > > >Just to say thank you to Leo Corbalis, Rob Prior, and Sigmo for their leads >and suggestions to a replacement of a 25A, 120VAC rotary selector switch. >None of the sources had anything of a high enough capacity, and as a total >greenhorn in electrical or electronic matters, I hesitated going the >relay/contacter route. > >Then my better half came up with a solution after she examined the broken >switch, and that was to use parts of a sheet of Lexan I happen to have >laying around to replace the broken face of the switch. A full day later, >and voila, its repaired and working! Now we will survive the early stages >of the 37th ice age this year. > >Many thanks to the List and the rapid responses it created to our dilemma. > >August > > ________________________________ Message 6 _____________________________________ Time: 09:04:50 AM PST US From: Robert McCallum Subject: Re: AeroElectric-List: Battery failure -- lessons and questions on dbmail-mx1 --> AeroElectric-List message posted by: Robert McCallum Frank & Dorothy wrote: >--> AeroElectric-List message posted by: Frank & Dorothy > >Hi, > >Thought you guys might benefit from my experience today with my car >battery >I recently installed an engine immobiliser after my car disappeared >overnight a couple of times > > Possibly unrelated. > I got a ride to the >nearest gas station, bought a battery (at an exorbitant price) and >borrowed a couple of spanners, and got back to the airfield and replaced >the battery. > > Re-attaching a couple of connections in the process. >Somewhat to my surprise, everything suddenly worked properly! > > Not necessarily surprising. >As I see it now, when the starter motor isn't turning, its coils have >less impedance/resistance than the rest of the circuitry in the car. >Hence, turning the key to 'start' would drop the voltage across the >warning lights so that they went out. But the battery couldn't provide >enough oomph to turn the starter motor, so from the battery's point of >view there was more or less a short circuit. > Very true. Almost always happens with a "dead" battery. > I'm thinking that probably >one (or more) of the battery's cells has died, so the battery couldn't >provide 12.5V, and some reduced amount of current. (I kept the bad >battery, and will investigate it with voltmeter, etc tomorrow) > > Possibly but not necessarily true. Remember those connections you renewed when you changed batteries? An extremely high resistant connection will display exactly the symptoms you describe. I can't count the number of times that I have encountered people with non starting cars with exactly the symptoms you describe whom I've been able to get started by simply disconnecting the battery cables, cleaning the connections and re-attaching them. Instant cure. Corrosion on the terminals of neglected batteries condemns many perfectly good batteries to the scrap heap. Part of battery maintenance is keeping the terminals clean, especially here in the "Great White North" where salt used on the roads in winter corrodes connections very rapidly. >I still don't see why adding more oomph via external battery and jumper >leads didn't get the car started. I guess that somehow the dead cell in >the bad battery was providing some kind of low-resistance path for the >juice from the good battery to flow through, instead of through the >starter motor??? But there was no noticeable heating of the jumper >leads, or loading down of the running car which I'd expect in that >situation. Also, I'd expect (but didn't see) sparks when I attached the >last jumper leads. > > These comments, (no sparks, no heating of the leads, no loading of the running car etc.) usually indicates a poorly connected cable or a cable connected to a corroded battery terminal displaying the above mentioned high resistance. "Most" battery cables which the average person has are totally useless. The average hardware/automotive store cables are of MUCH too small a gauge. A useful jumper cable set should be at least #2 gauge copper wire or heavier with solid copper clamps attached to brightly cleaned connections on both the booster and boosted cars. (vehicles) The "cheap" cables properly connected WILL heat up. This heat is energy not available for starting. No heat and /or no spark and no loading of the booster car means no connection, no current flow hence no boost. >Another question that I'm wondering about: How can putting jumper leads >on a car blow its computer (as I was warned about today)? Surely, from >the computer's point of view, it can't tell whether the flow of >electricity its receiving is coming from the car's own battery, an >external battery, or some combination of both? If 'surges of >electricity' are the culprit as someone contended today, then surely >disconnecting a near-dead battery and connecting a new fully-charged >battery is worse than jumpering the full battery across the near-dead >one? And what about the voltage transients when the alternator starts >up? Is this "putting jumper leads on a car blow its computer" just a myth? > > Generally happens if the boosted car battery is "dead" or disconnected due to bad connections (see above) and you get the cables connected backwards thus powering the computer with reverse polarity. Yes, this can "blow" the computer. Properly connected cables will not cause a problem just as your analysis suggests. >BobN, I'd appreciate it if you would satisy my curiosity over the >physics of what happened today. > > Your turn Bob. >LESSONS: >1. When your battery suggests that it is about to die, take heed! > > Good advice ! > <>2. Somehow, a bad battery can prevent a parallel good battery from > working! This may be especially relevant for people installing dual > batteries in their aircraft -- if you can't isolate a bad battery, it > may prevent starting (or even take down the electrical system???) even > if you have a good battery (or perhaps even a running > alternator???)alongside. Not usually, but, I suppose, sometimes possible. > <>Frank Bob McC ________________________________ Message 7 _____________________________________ Time: 09:43:07 AM PST US From: "Mike Holland" Subject: Re: AeroElectric-List: Z13a Pre-flight alt test procedure? --> AeroElectric-List message posted by: "Mike Holland" Does your alternator have a built in regulator. Are you wired per Z-24? Yes (Vans 60amp) and Yes. IF NOT . . . then there's nothing at risk for turning the main alternator OFF and aux alternator ON during runup to check your ignition system(s). If you have Z-24 and internally regulated alternator, turn the main alternator OFF and aux alternator ON at engine idle before runup . . . after run up and at engine idle, turn aux alternator OFF and main alternator back ON. Don't concern yourself with voltage readings while aux alternator is ON . . . just not that the current output comes up. You might want to consider running BOTH alternator leads through ONE hall-effect sensor. Since the alternators are tested/used independently from each other, the one current sensor can be used to monitor functionality of both alternators. Would have done that had the b-leads been in some proximity. The main alternator is connected to the Z24 relay on the engine side, lower right, below the battery case and the Aux alternator is high and it's lead goes through the firewall to the regulator mounted inside. I'm using AmpLoc sensors for both so it will interesting to see how easily they are to calibrate. There wired to the Grand Rapid EIS using 2 of the available Aux inputs. 4.8 volts supplied. I won't be concerned about accuracy so much as repeatability since i think if it more as a benchmark and measure of day to day performance. Thanks ________________________________ Message 8 _____________________________________ Time: 11:29:52 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Battery failure -- lessons and questions --> AeroElectric-List message posted by: "Paul Messinger" Another thing to consider. There is a ground jumper from the engine block to the frame. I had this come off and got either (1) no starting or (2) the lights going out (3) or it worked just fine. With the jumper missing your ground path is thru the wheel bearings etc which are a variable resistor. In any event fixing the ground jumper remover ALL the above problems for me. Paul ----- Original Message ----- From: "Robert McCallum" Subject: Re: AeroElectric-List: Battery failure -- lessons and questions on dbmail-mx1 > --> AeroElectric-List message posted by: Robert McCallum > > Frank & Dorothy wrote: > > >--> AeroElectric-List message posted by: Frank & Dorothy > > > >Hi, > > > >Thought you guys might benefit from my experience today with my car > >battery > >I recently installed an engine immobiliser after my car disappeared > >overnight a couple of times > > > > > Possibly unrelated. > > > I got a ride to the > >nearest gas station, bought a battery (at an exorbitant price) and > >borrowed a couple of spanners, and got back to the airfield and replaced > >the battery. > > > > > Re-attaching a couple of connections in the process. > > >Somewhat to my surprise, everything suddenly worked properly! > > > > > Not necessarily surprising. > > >As I see it now, when the starter motor isn't turning, its coils have > >less impedance/resistance than the rest of the circuitry in the car. > >Hence, turning the key to 'start' would drop the voltage across the > >warning lights so that they went out. But the battery couldn't provide > >enough oomph to turn the starter motor, so from the battery's point of > >view there was more or less a short circuit. > > > Very true. Almost always happens with a "dead" battery. > > > I'm thinking that probably > >one (or more) of the battery's cells has died, so the battery couldn't > >provide 12.5V, and some reduced amount of current. (I kept the bad > >battery, and will investigate it with voltmeter, etc tomorrow) > > > > > Possibly but not necessarily true. Remember those connections you > renewed when you changed batteries? An extremely high resistant > connection will display exactly the symptoms you describe. I can't count > the number of times that I have encountered people with non starting > cars with exactly the symptoms you describe whom I've been able to get > started by simply disconnecting the battery cables, cleaning the > connections and re-attaching them. Instant cure. Corrosion on the > terminals of neglected batteries condemns many perfectly good batteries > to the scrap heap. Part of battery maintenance is keeping the terminals > clean, especially here in the "Great White North" where salt used on the > roads in winter corrodes connections very rapidly. > > >I still don't see why adding more oomph via external battery and jumper > >leads didn't get the car started. I guess that somehow the dead cell in > >the bad battery was providing some kind of low-resistance path for the > >juice from the good battery to flow through, instead of through the > >starter motor??? But there was no noticeable heating of the jumper > >leads, or loading down of the running car which I'd expect in that > >situation. Also, I'd expect (but didn't see) sparks when I attached the > >last jumper leads. > > > > > These comments, (no sparks, no heating of the leads, no loading of the > running car etc.) usually indicates a poorly connected cable or a cable > connected to a corroded battery terminal displaying the above mentioned > high resistance. "Most" battery cables which the average person has are > totally useless. The average hardware/automotive store cables are of > MUCH too small a gauge. A useful jumper cable set should be at least #2 > gauge copper wire or heavier with solid copper clamps attached to > brightly cleaned connections on both the booster and boosted cars. > (vehicles) The "cheap" cables properly connected WILL heat up. This heat > is energy not available for starting. No heat and /or no spark and no > loading of the booster car means no connection, no current flow hence no > boost. > > >Another question that I'm wondering about: How can putting jumper leads > >on a car blow its computer (as I was warned about today)? Surely, from > >the computer's point of view, it can't tell whether the flow of > >electricity its receiving is coming from the car's own battery, an > >external battery, or some combination of both? If 'surges of > >electricity' are the culprit as someone contended today, then surely > >disconnecting a near-dead battery and connecting a new fully-charged > >battery is worse than jumpering the full battery across the near-dead > >one? And what about the voltage transients when the alternator starts > >up? Is this "putting jumper leads on a car blow its computer" just a myth? > > > > > Generally happens if the boosted car battery is "dead" or disconnected > due to bad connections (see above) and you get the cables connected > backwards thus powering the computer with reverse polarity. Yes, this > can "blow" the computer. Properly connected cables will not cause a > problem just as your analysis suggests. > > >BobN, I'd appreciate it if you would satisy my curiosity over the > >physics of what happened today. > > > > > Your turn Bob. > > >LESSONS: > >1. When your battery suggests that it is about to die, take heed! > > > > > Good advice ! > > > <>2. Somehow, a bad battery can prevent a parallel good battery from > > working! This may be especially relevant for people installing dual > > batteries in their aircraft -- if you can't isolate a bad battery, it > > may prevent starting (or even take down the electrical system???) even > > if you have a good battery (or perhaps even a running > > alternator???)alongside. > > Not usually, but, I suppose, sometimes possible. > > > <>Frank > > > Bob McC > > ________________________________ Message 9 _____________________________________ Time: 11:29:52 AM PST US From: "Paul Messinger" Subject: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Paul Messinger" > then there's nothing at risk for turning > the main alternator OFF and aux alternator ON during runup to > check your ignition system(s). ALL the Jap internally regulated alternators INCL ND (that I have looked at and that is quite a few but no where all types and ND alone has several different designs) cannot be turned off once turned on and running. Toggle the alt ON OFF connection all you want but the internal regulator is LATCHED on. IS vans ND different?? Its possible to disconnect the "B" lead using the CB but that is disconnecting not turning off the alternator. Paul ________________________________ Message 10 ____________________________________ Time: 12:49:01 PM PST US From: "Alex Peterson" Subject: RE: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Alex Peterson" > ALL the Jap internally regulated alternators INCL ND (that I > have looked at and that is quite a few but no where all types > and ND alone has several different designs) cannot be turned > off once turned on and running. > > Toggle the alt ON OFF connection all you want but the > internal regulator is LATCHED on. > > IS vans ND different?? Paul, I have an internally regulated ND 40amp alternator (Niagara Air Parts) which came with my Aerosport engine. The above statement is not true in my case. My master switch is a three position setup, when the engine is running and I turn off the alternator (which disconnects the 5 amp supply to the alternator), the bus voltage drops to battery voltage. Turn it on, 14 volts, off 12, etc.. Alex Peterson RV6-A 569 hours Maple Grove, MN http://www.home.earthlink.net/~alexpeterson/ ________________________________ Message 11 ____________________________________ Time: 01:12:47 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Paul Messinger" Thanks that clears that up. I wonder is your a rebuilt unit or OEM original as the internal regulators might be wired differently. ALL my investigations were on alternators off autos and none from rebuilders. Paul ----- Original Message ----- From: "Alex Peterson" Subject: RE: AeroElectric-List: turning off an internally regulated alternator > --> AeroElectric-List message posted by: "Alex Peterson" > > > ALL the Jap internally regulated alternators INCL ND (that I > > have looked at and that is quite a few but no where all types > > and ND alone has several different designs) cannot be turned > > off once turned on and running. > > > > Toggle the alt ON OFF connection all you want but the > > internal regulator is LATCHED on. > > > > IS vans ND different?? > > Paul, > > I have an internally regulated ND 40amp alternator (Niagara Air Parts) which > came with my Aerosport engine. The above statement is not true in my case. > My master switch is a three position setup, when the engine is running and I > turn off the alternator (which disconnects the 5 amp supply to the > alternator), the bus voltage drops to battery voltage. Turn it on, 14 > volts, off 12, etc.. > > Alex Peterson > RV6-A 569 hours > Maple Grove, MN > > http://www.home.earthlink.net/~alexpeterson/ > > ________________________________ Message 12 ____________________________________ Time: 01:16:10 PM PST US From: "Ed Anderson" Subject: Re: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Ed Anderson" I originally thought my auto alternator was controllable by the voltage to its field coil. I even convinced myself of this by pulling the 5 amp field coil circuit breaker and starting the engine - sure enough only battery busy voltage. I then pushed in the circuit breaker and sure enough 14.2 volts from the alternator. I then again pulled the alternator field coil circuit breaker and Whoa! it stated at 14.2 volts. A little research on alternators revealed the fact that once the alternator is producing voltage it no longer needs external voltage to the field coil (apparently its provided internally). So once this initial external "boot strap" voltage is provided and the alternator starts producing - the external voltage is no longer required and the alternator can not be disabled by removing it (at least for my alternator and most auto alternators with internal regulation). Your mileage may vary Ed Anderson RV-6A N494BW Matthew, NC ----- Original Message ----- From: "Alex Peterson" Subject: RE: AeroElectric-List: turning off an internally regulated alternator > --> AeroElectric-List message posted by: "Alex Peterson" > > > ALL the Jap internally regulated alternators INCL ND (that I > > have looked at and that is quite a few but no where all types > > and ND alone has several different designs) cannot be turned > > off once turned on and running. > > > > Toggle the alt ON OFF connection all you want but the > > internal regulator is LATCHED on. > > > > IS vans ND different?? > > Paul, > > I have an internally regulated ND 40amp alternator (Niagara Air Parts) which > came with my Aerosport engine. The above statement is not true in my case. > My master switch is a three position setup, when the engine is running and I > turn off the alternator (which disconnects the 5 amp supply to the > alternator), the bus voltage drops to battery voltage. Turn it on, 14 > volts, off 12, etc.. > > Alex Peterson > RV6-A 569 hours > Maple Grove, MN > > http://www.home.earthlink.net/~alexpeterson/ > > ________________________________ Message 13 ____________________________________ Time: 01:28:10 PM PST US From: "Vincent Welch" Subject: Re: AeroElectric-List: Re: Load dump comments --> AeroElectric-List message posted by: "Vincent Welch" Paul, What wattage rating would the 1/2 ohm resistor require? Vince >From: "Paul Messinger" >Reply-To: aeroelectric-list@matronics.com >To: >Subject: Re: AeroElectric-List: Re: Load dump comments >Date: Sat, 8 Jan 2005 12:59:16 -0800 > >--> AeroElectric-List message posted by: "Paul Messinger" > > >Its wired exactly as Bob shows. > >The power path is thru the CB that powers the relay (in the case of a "B" >lead the contactor) and the crow bar shorts the CB to ground and the 400 >amps is thru the wiring and thru the CB and OVP SCR. There is no HI current >thru the field. > >Draw a wire from the load side of the CB to ground (thats the OVP). The >resulting circuit is the battery to the CB to the OVP to ground. The OVP >tripps and its scr shorts the OVP to ground. Net result is the CB is >directly across the battery plus wiring. The modern battery will provide >more than 1000 amps (some closer to 2000 amps) across the CB with very >short >leads. One solution is a 1/8 to 1/2 ohm resistor in the OVP shorting path >to >limit current and still blow the CB. > >I got 730 amps with shorter but realistic leads and the Powersonic 12v18ah >battery that Bob promotes. Far cry from a Gill flooded cell acft battery. > >I tried 3 different popular 5 amp CB brands and all showed at least 50 ms >to >open. (and that is when they are warmed up). After a couple of hours at >rest >the CB can take more than 80MS to trip. Yes they are that slow. > >Paul > >----- Original Message ----- >From: "Kevin Horton" >To: >Subject: Re: AeroElectric-List: Re: Load dump comments > > > > --> AeroElectric-List message posted by: Kevin Horton > > > > > I'm interested as to which two items the crowbar was shorting when > > these large currents were measured. I'm assuming this is a different > > application than the crowbar OV protection that Bod espouses, where > > the crowbar shorts out the field circuit, popping a 5A CB. I can't > > imagine how 400 to 700 amps could be generated in the field circuit > > before the 5A CB popped. Are CBs that slow to trip? Or, was this a > > different application of a crowbar? > > > > Kevin Horton > > > > >--> AeroElectric-List message posted by: "Paul Messinger" > > > > > > >The huge current loop during a shorting crowbar event generates a large > > >magnetic field that can magnetize steel and mess up your compass > > >calibration. > > > > > >I got 400 amps with longer that likely wires. When I simulated my >aircraft > > >wiring I got over 700 amps. > > > > > >Measurements were made with calibrated equipment. as well as being > > >repeatable. > > > > > >If this does not bother you, be my guest. > > > > > >Paul > > > > > > > > >> Sure that sounds scary but I'll wait for the report before getting > > >> concerned. With 6 feet of 18awg wire in series with a C/B, an SCR, >and > > >> several connections it may be possible to get a couple of hundred >amps > > >> of instantaneous current flowing but so what? It is drawing down the > > >> voltage which is what we want. > > >> > > >> The interesting thing to me is a nuisance trip. It sounds like it is > > >> possible to ramp up the alternator output during the delay (40 ms?) > > >> waiting for the OV contactor to open. However I haven't seen any >reason > > > > to be concerned about that yet and I will await the report. > > > > > > ________________________________ Message 14 ____________________________________ Time: 01:36:47 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Paul Messinger" Your alternator internal regulator sounds like what I have seen. There is an internal path from the "B" lead that powers the regulator as well as internal regulator logic that "latches" the regulator in the ON condition Clearly different brands and differenced between types of the same brand are out there. Both of the below messages demonstrate this. Can anyone who has a Vans rebuilt ND alternator comment on how that version works with respect to this thread. Paul ----- Original Message ----- From: "Ed Anderson" Subject: Re: AeroElectric-List: turning off an internally regulated alternator > --> AeroElectric-List message posted by: "Ed Anderson" > > I originally thought my auto alternator was controllable by the voltage to > its field coil. I even convinced myself of this by pulling the 5 amp field > coil circuit breaker and starting the engine - sure enough only battery busy > voltage. I then pushed in the circuit breaker and sure enough 14.2 volts > from the alternator. I then again pulled the alternator field coil circuit > breaker and Whoa! it stated at 14.2 volts. A little research on alternators > revealed the fact that once the alternator is producing voltage it no longer > needs external voltage to the field coil (apparently its provided > internally). So once this initial external "boot strap" voltage is provided > and the alternator starts producing - the external voltage is no longer > required and the alternator can not be disabled by removing it (at least for > my alternator and most auto alternators with internal regulation). Your > mileage may vary > > Ed Anderson > RV-6A N494BW > Matthew, NC > ----- Original Message ----- > From: "Alex Peterson" > To: > Subject: RE: AeroElectric-List: turning off an internally regulated > alternator > > > > --> AeroElectric-List message posted by: "Alex Peterson" > > > > > > ALL the Jap internally regulated alternators INCL ND (that I > > > have looked at and that is quite a few but no where all types > > > and ND alone has several different designs) cannot be turned > > > off once turned on and running. > > > > > > Toggle the alt ON OFF connection all you want but the > > > internal regulator is LATCHED on. > > > > > > IS vans ND different?? > > > > Paul, > > > > I have an internally regulated ND 40amp alternator (Niagara Air Parts) > which > > came with my Aerosport engine. The above statement is not true in my > case. > > My master switch is a three position setup, when the engine is running and > I > > turn off the alternator (which disconnects the 5 amp supply to the > > alternator), the bus voltage drops to battery voltage. Turn it on, 14 > > volts, off 12, etc.. > > > > Alex Peterson > > RV6-A 569 hours > > Maple Grove, MN > > > > http://www.home.earthlink.net/~alexpeterson/ > > > > > > ________________________________ Message 15 ____________________________________ Time: 01:36:47 PM PST US From: "Alex Peterson" Subject: RE: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Alex Peterson" Mine is (was) new five years ago. Call to confirm, but I seem to recall that Aerosport Power got them from Niagara Air Parts. See http://www.niagaraairparts.com/ 3/4's down the page. Alex Peterson > --> AeroElectric-List message posted by: "Paul Messinger" > --> > > Thanks that clears that up. I wonder is your a rebuilt unit > or OEM original as the internal regulators might be wired > differently. ALL my investigations were on alternators off > autos and none from rebuilders. > > Paul > > ----- Original Message ----- > From: "Alex Peterson" > To: > Subject: RE: AeroElectric-List: turning off an internally > regulated alternator > > > > --> AeroElectric-List message posted by: "Alex Peterson" > > > > > > ALL the Jap internally regulated alternators INCL ND (that I have > > > looked at and that is quite a few but no where all types and ND > > > alone has several different designs) cannot be turned off once > > > turned on and running. > > > > > > Toggle the alt ON OFF connection all you want but the internal > > > regulator is LATCHED on. > > > > > > IS vans ND different?? > > > > Paul, > > > > I have an internally regulated ND 40amp alternator (Niagara > Air Parts) > which > > came with my Aerosport engine. The above statement is not > true in my > case. > > My master switch is a three position setup, when the engine > is running > > and > I > > turn off the alternator (which disconnects the 5 amp supply to the > > alternator), the bus voltage drops to battery voltage. > Turn it on, 14 > > volts, off 12, etc.. > > > > Alex Peterson > > RV6-A 569 hours > > Maple Grove, MN > > > > http://www.home.earthlink.net/~alexpeterson/ > > > > > > > ========= > Matronics Forums. > ========= > http://www.matronics.com/FAQ/AeroElectric-List.htm > ========= > > > > > ________________________________ Message 16 ____________________________________ Time: 01:52:57 PM PST US From: "Vincent Welch" Subject: AeroElectric-List: Load Dump Question --> AeroElectric-List message posted by: "Vincent Welch" Hey guys, I have been watching this "Battle Of The Titans" with great interest. I have a question from one a bit lower down the food chain:) It has always been my understanding that the purpose of the OV circuit was to protect my avionics from a runaway alternator. The alternator or regulator has already failed and the voltage is climbing. The crowbar opens the circuit to limit prevent damage to my expensive avionics. The alternator/regulator has already failed, its trash, so I open the B-lead under load, I get a load dump event. So what? Why do I care about trying to protect the alternator now? I can understand limiting the crowbar circuit current and adding a resistor sounds like a simple easy solution to that problem. What am I missing here? Please further educate me. Vince ________________________________ Message 17 ____________________________________ Time: 02:00:52 PM PST US From: "Paul Messinger" Subject: AeroElectric-List: OVP current limiting --> AeroElectric-List message posted by: "Paul Messinger" New subject line above First lets pick a resistance from the following table to suit your comfort. OHM aprox current 0.1 120 amps 0.2 60 amps 0.3 40 amps 0.4 30 amps 0.5 24 amps Any of the above resistance values will blow most CB's in about the same time. Any value is better than a dead short plus wiring drops. (I get 400-700+ amps depending on wiring length etc and battery used with no series resistor.) I would recommend 0.2 to 0.4 ohms as reasonable compromise. Around 10 times the CB rating ends up with the fastest possible trip time. Thus 50 amps is more than enough for a 5 amp CB. Wattage is not important but the resistors ability pass the current pulse is the driving parameter. So a 1/2 watt might be OK, I would use a one watt to be sure. Most any brand or type will work fine. If you made your OVP from Bob's plans it can be added to the circuit, or simply added in line externally. I will have more comments on the Crowbar approach and how its different from the classic short and blow a fuse or CB protecting avionics etc. Not quite the same issues and concerns. Paul PS Thanks for asking ----- Original Message ----- From: "Vincent Welch" Subject: Re: AeroElectric-List: Re: Load dump comments > --> AeroElectric-List message posted by: "Vincent Welch" > > Paul, > > What wattage rating would the 1/2 ohm resistor require? > > Vince > > >From: "Paul Messinger" > >Reply-To: aeroelectric-list@matronics.com > >To: > >Subject: Re: AeroElectric-List: Re: Load dump comments > >Date: Sat, 8 Jan 2005 12:59:16 -0800 > > > >--> AeroElectric-List message posted by: "Paul Messinger" > > > > > >Its wired exactly as Bob shows. > > > >The power path is thru the CB that powers the relay (in the case of a "B" > >lead the contactor) and the crow bar shorts the CB to ground and the 400 > >amps is thru the wiring and thru the CB and OVP SCR. There is no HI current > >thru the field. > > > >Draw a wire from the load side of the CB to ground (thats the OVP). The > >resulting circuit is the battery to the CB to the OVP to ground. The OVP > >tripps and its scr shorts the OVP to ground. Net result is the CB is > >directly across the battery plus wiring. The modern battery will provide > >more than 1000 amps (some closer to 2000 amps) across the CB with very > >short > >leads. One solution is a 1/8 to 1/2 ohm resistor in the OVP shorting path > >to > >limit current and still blow the CB. > > > >I got 730 amps with shorter but realistic leads and the Powersonic 12v18ah > >battery that Bob promotes. Far cry from a Gill flooded cell acft battery. > > > >I tried 3 different popular 5 amp CB brands and all showed at least 50 ms > >to > >open. (and that is when they are warmed up). After a couple of hours at > >rest > >the CB can take more than 80MS to trip. Yes they are that slow. > > > >Paul > > > >----- Original Message ----- > >From: "Kevin Horton" > >To: > >Subject: Re: AeroElectric-List: Re: Load dump comments > > > > > > > --> AeroElectric-List message posted by: Kevin Horton > > > > > > > > I'm interested as to which two items the crowbar was shorting when > > > these large currents were measured. I'm assuming this is a different > > > application than the crowbar OV protection that Bod espouses, where > > > the crowbar shorts out the field circuit, popping a 5A CB. I can't > > > imagine how 400 to 700 amps could be generated in the field circuit > > > before the 5A CB popped. Are CBs that slow to trip? Or, was this a > > > different application of a crowbar? > > > > > > Kevin Horton > > > > > > >--> AeroElectric-List message posted by: "Paul Messinger" > > > > > > > > > >The huge current loop during a shorting crowbar event generates a large > > > >magnetic field that can magnetize steel and mess up your compass > > > >calibration. > > > > > > > >I got 400 amps with longer that likely wires. When I simulated my > >aircraft > > > >wiring I got over 700 amps. > > > > > > > >Measurements were made with calibrated equipment. as well as being > > > >repeatable. > > > > > > > >If this does not bother you, be my guest. > > > > > > > >Paul > > > > > > > > > > > >> Sure that sounds scary but I'll wait for the report before getting > > > >> concerned. With 6 feet of 18awg wire in series with a C/B, an SCR, > >and > > > >> several connections it may be possible to get a couple of hundred > >amps > > > >> of instantaneous current flowing but so what? It is drawing down the > > > >> voltage which is what we want. > > > >> > > > >> The interesting thing to me is a nuisance trip. It sounds like it is > > > >> possible to ramp up the alternator output during the delay (40 ms?) > > > >> waiting for the OV contactor to open. However I haven't seen any > >reason > > > > > to be concerned about that yet and I will await the report. > > > > > > > > > > > > ________________________________ Message 18 ____________________________________ Time: 02:02:17 PM PST US From: "Mark Banus" Subject: AeroElectric-List: Pilot stick grip priority options rev B --> AeroElectric-List message posted by: "Mark Banus" Bob, I am about to start building your circuit for pilot priority. I intend to use 1N4001 diodes and a T9AP5D52-12 relay. Is there a more appropriate relay for this application? Thanks Mark Banus Glasair S II S FT ________________________________ Message 19 ____________________________________ Time: 02:30:23 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Load Dump Question --> AeroElectric-List message posted by: "Paul Messinger" As I recall the original start of this thread was early last year when there were failures of Van's rebuilt alternators. Bob and others questioned the quality of the rebuilt regulator in the Van's alternator. Personally I have never seen any real proof of what was the true cause. I have real trouble believing Van would sell substandard alternators. ALL standard alternator internal regulators are protected against worst case load dump. Any way You are correct that in the case of a real alternator regulator HI voltage failure, the only solution is to cut the "B" lead and "so what" if that causes an isolated load dump that the alternator cannot take. However if the alternator is working fine and the battery is disconnected the resulting load dump is distributed to the bus and can cause harm depending on what is on the bus and how big the load dump is. There are a couple of solutions to this. First a transorb big enough to clamp the load dump hi voltage. This has nothing directly to do with any OVP device present. However Bob's crow bar OVP will trigger with the above load dump and this results in the hi current during its operation that some of us object to. A simple addition of a small value series resistor fixes that. If the load dump is a result of the "B" lead opening the load dump issue is contained to the alternator where you may or may not damage the alternator internal regulator. A transorb on the alternator side of the "B" lead contactor will protect the alternator if the regulator is not up to the task. This is a second transorb as one needs to be on the Bus side also. If the load dump is a result of disconnecting a charging battery the load dump is delivered to the aircraft bus and potential damage can result to your avionics. Its likely the OVP will trip but not in time in all cases to prevent a short hi voltage pulse on the BUS. The OVP takes some time to start clamping (5-10MS?) and much longer (50-100ms) to disconnect the alternator thru the "B" lead contactor. Even 5 ms is long with a 60V or higher pulse on BUS. So some of us feel the need for the "Transorb" to keep the BUS voltages clamped while the OVP can act. The transorb acts not in 5 MS but in 1/2 pico second 10,000+ times faster and faster than any damage can start. If the failure is a failed hi voltage alternator the transorb clamps the voltage while the OVP acts. Both arte needed in the safest system. If this does not answer your concerns ask more as everyone benefits from such a "conversation" Paul ----- Original Message ----- From: "Vincent Welch" Subject: AeroElectric-List: Load Dump Question > --> AeroElectric-List message posted by: "Vincent Welch" > > Hey guys, I have been watching this "Battle Of The Titans" with great > interest. I have a question from one a bit lower down the food chain:) > > It has always been my understanding that the purpose of the OV circuit was > to protect my avionics from a runaway alternator. The alternator or > regulator has already failed and the voltage is climbing. The crowbar opens > the circuit to limit prevent damage to my expensive avionics. The > alternator/regulator has already failed, its trash, so I open the B-lead > under load, I get a load dump event. So what? Why do I care about trying > to protect the alternator now? > > I can understand limiting the crowbar circuit current and adding a resistor > sounds like a simple easy solution to that problem. > > What am I missing here? Please further educate me. > > Vince > > ________________________________ Message 20 ____________________________________ Time: 02:30:23 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: turning off an internally regulated alternator --> AeroElectric-List message posted by: "Paul Messinger" Thanks I will try to get more info monday when they are open. Paul ----- Original Message ----- From: "Alex Peterson" Subject: RE: AeroElectric-List: turning off an internally regulated alternator > --> AeroElectric-List message posted by: "Alex Peterson" > > > Mine is (was) new five years ago. Call to confirm, but I seem to recall > that Aerosport Power got them from Niagara Air Parts. See > http://www.niagaraairparts.com/ 3/4's down the page. > > Alex Peterson > > > --> AeroElectric-List message posted by: "Paul Messinger" > > --> > > > > Thanks that clears that up. I wonder is your a rebuilt unit > > or OEM original as the internal regulators might be wired > > differently. ALL my investigations were on alternators off > > autos and none from rebuilders. > > > > Paul > > > > ----- Original Message ----- > > From: "Alex Peterson" > > To: > > Subject: RE: AeroElectric-List: turning off an internally > > regulated alternator > > > > > > > --> AeroElectric-List message posted by: "Alex Peterson" > > > > > > > > > ALL the Jap internally regulated alternators INCL ND (that I have > > > > looked at and that is quite a few but no where all types and ND > > > > alone has several different designs) cannot be turned off once > > > > turned on and running. > > > > > > > > Toggle the alt ON OFF connection all you want but the internal > > > > regulator is LATCHED on. > > > > > > > > IS vans ND different?? > > > > > > Paul, > > > > > > I have an internally regulated ND 40amp alternator (Niagara > > Air Parts) > > which > > > came with my Aerosport engine. The above statement is not > > true in my > > case. > > > My master switch is a three position setup, when the engine > > is running > > > and > > I > > > turn off the alternator (which disconnects the 5 amp supply to the > > > alternator), the bus voltage drops to battery voltage. > > Turn it on, 14 > > > volts, off 12, etc.. > > > > > > Alex Peterson > > > RV6-A 569 hours > > > Maple Grove, MN > > > > > > http://www.home.earthlink.net/~alexpeterson/ > > > > > > > > > > > > ========= > > Matronics Forums. > > ========= > > http://www.matronics.com/FAQ/AeroElectric-List.htm > > ========= > > > > > > > > > > > > ________________________________ Message 21 ____________________________________ Time: 03:11:10 PM PST US From: "Dan O'Brien" Subject: AeroElectric-List: Garmin/Microencoder wiring question --> AeroElectric-List message posted by: "Dan O'Brien" I am wiring the serial connection from my Microencoder to my Garmin 430. The Garmin documentation shows a shielded twisted pair with the shield grounded a both ends and the Attitude Common pin (part of the twisted pair) connected to the shield at the Garmin and connected to the Power Ground wire at the encoder. Question: Does it matter whether the Attitude Common pin is grounded at the Garmin given that it is also grounded through the encoder? I'm asking because I already wired the Garmin end without connecting it to the shield. I can always rip the pin out and do it over, but would prefer not to :). ________________________________ Message 22 ____________________________________ Time: 03:23:03 PM PST US From: "Dan O'Brien" Subject: AeroElectric-List: General radio grounding question --> AeroElectric-List message posted by: "Dan O'Brien" My Garmin 430 and UPS SL30 both have case ground studs. Question: Do the ground studs run to Power Ground through the radios, or are they something completely different? I'm puzzling over this because my Garmin came with a partial harness that connects shields to the case, which is simply depicted with a ground symbol in the installation manual. I'm assuming that this means that the case is connected to the Aircraft ground through the Power Ground pin in the harness. If this were not the case, how would I know from the ground symbol depicted in the manual that the case ground is something different than the aircraft power ground? There is no mention in the manual that the shields should be grounded to the case INSTEAD OF the aircraft power ground. If I sound a bit confused, it's because I AM ! ________________________________ Message 23 ____________________________________ Time: 04:03:07 PM PST US From: "Wayne Sweet" Subject: Re: AeroElectric-List: Garmin/Microencoder wiring question --> AeroElectric-List message posted by: "Wayne Sweet" I just finished wiring my 430 with encoder, but the input was the 11 pin (gray code, I think it's referred to as). The Garmin wiring diagrams are wrong in this and one other in respect to the grounding at both ends of the shields. Do not ground both ends of the shields or the least that will (could) cause a ground plane loop. I called, and asked Garmin tech guys at the AOPA convention about the shield grounding at both ends for the GI-106A obs, and at first I received somewhat blank stares. Then finally got a definitive NO, do not ground shields at both ends. I know for a fact, that grounding the shields between the 430 and the audio panel (in my case, PS Engineering's PMA6000) will cause havoc with the com output. On mine the altitude common is simply ground. This was the answer I finally got from Garmin; the TransCal (my encoder) people didn't know and in fact ask me to call them back when I found the answer. If the encoder pin-out has a Altitude Common, then of course use it. BTW, I would NEVER do that sort of wiring job myself (GNS430, GI-106A, PMA6000, Navaid Device, Terra NAV/COM, Terra Marker Beacon). After having done it, I learned of FastStack by Approach Systems. Good luck; Oh I learned that the ungrounded end of the shields should be heat shrink wrapped to prevent the shield from touching any structure, other wires, thereby causing a ground plane loop. Wayne ----- Original Message ----- From: "Dan O'Brien" Subject: AeroElectric-List: Garmin/Microencoder wiring question > --> AeroElectric-List message posted by: "Dan O'Brien" > > I am wiring the serial connection from my Microencoder to my Garmin > 430. The Garmin documentation shows a shielded twisted pair with the > shield grounded a both ends and the Attitude Common pin (part of the > twisted pair) connected to the shield at the Garmin and connected to the > Power Ground wire at the encoder. Question: Does it matter whether the > Attitude Common pin is grounded at the Garmin given that it is also > grounded through the encoder? I'm asking because I already wired the > Garmin end without connecting it to the shield. I can always rip the pin > out and do it over, but would prefer not to :). > > > I am using the free version of SPAMfighter for private users. It has removed 698 spam emails to date. Paying users do not have this message in their emails. Try www.SPAMfighter.com for free now! ________________________________ Message 24 ____________________________________ Time: 04:06:32 PM PST US From: "Wayne Sweet" Subject: Re: AeroElectric-List: General radio grounding question --> AeroElectric-List message posted by: "Wayne Sweet" The assumption is (by Garmin) is the 430 tray is connected to the airframe through mounting screws, and the ground terminals (I found the purpose of those at AOPA convention) is connected to the tray, and the tray to the airframe. At least that's the way mine is and it works. Wayne ----- Original Message ----- From: "Dan O'Brien" Subject: AeroElectric-List: General radio grounding question > --> AeroElectric-List message posted by: "Dan O'Brien" > > My Garmin 430 and UPS SL30 both have case ground studs. Question: Do the > ground studs run to Power Ground through the radios, or are they something > completely different? > > I'm puzzling over this because my Garmin came with a partial harness that > connects shields to the case, which is simply depicted with a ground > symbol > in the installation manual. I'm assuming that this means that the case is > connected to the Aircraft ground through the Power Ground pin in the > harness. If this were not the case, how would I know from the ground > symbol depicted in the manual that the case ground is something different > than the aircraft power ground? There is no mention in the manual that > the > shields should be grounded to the case INSTEAD OF the aircraft power > ground. > > If I sound a bit confused, it's because I AM ! > > > I am using the free version of SPAMfighter for private users. It has removed 698 spam emails to date. Paying users do not have this message in their emails. Try www.SPAMfighter.com for free now! ________________________________ Message 25 ____________________________________ Time: 04:20:51 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Load Dump Question --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 02:26 PM 1/22/2005 -0800, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >As I recall the original start of this thread was early last year when there >were failures of Van's rebuilt alternators. Bob and others questioned the >quality of the rebuilt regulator in the Van's alternator. > >Personally I have never seen any real proof of what was the true cause. I >have real trouble believing Van would sell substandard alternators. ALL >standard alternator internal regulators are protected against worst case >load dump. > >Any way You are correct that in the case of a real alternator regulator HI >voltage failure, the only solution is to cut the "B" lead and "so what" if >that causes an isolated load dump that the alternator cannot take. > >However if the alternator is working fine and the battery is disconnected >the resulting load dump is distributed to the bus and can cause harm >depending on what is on the bus and how big the load dump is. > >There are a couple of solutions to this. First a transorb big enough to >clamp the load dump hi voltage. This has nothing directly to do with any OVP >device present. > >However Bob's crow bar OVP will trigger with the above load dump and this >results in the hi current during its operation that some of us object to. A >simple addition of a small value series resistor fixes that. If the battery is off line and the crowbar "trips" there is no high current pulse. The alternator is physically incapable of delivering more than a few percent above rated current. Once the battery is out of the loop, a crowbar trip sinks the relatively low current of the alternator . . . the alternator looses excitation and dies. >If the load dump is a result of the "B" lead opening the load dump issue is >contained to the alternator where you may or may not damage the alternator >internal regulator. A transorb on the alternator side of the "B" lead >contactor will protect the alternator if the regulator is not up to the >task. This is a second transorb as one needs to be on the Bus side also. Why? if load dump energies come from the alternator, one Transorb at the alternator's b-lead terminal should suffice for all cases. >If the load dump is a result of disconnecting a charging battery the load >dump is delivered to the aircraft bus and potential damage can result to >your avionics. Its likely the OVP will trip but not in time in all cases to >prevent a short hi voltage pulse on the BUS. The OVP takes some time to >start clamping (5-10MS?) and much longer (50-100ms) to disconnect the >alternator thru the "B" lead contactor. Even 5 ms is long with a 60V or >higher pulse on BUS. > >So some of us feel the need for the "Transorb" to keep the BUS voltages >clamped while the OVP can act. The transorb acts not in 5 MS but in 1/2 pico >second 10,000+ times faster and faster than any damage can start. > >If the failure is a failed hi voltage alternator the transorb clamps the >voltage while the OVP acts. Both arte needed in the safest system. > >If this does not answer your concerns ask more as everyone benefits from >such a "conversation" Agreed! Bob . . . ________________________________ Message 26 ____________________________________ Time: 04:44:12 PM PST US From: "Vincent Welch" Subject: Re: AeroElectric-List: Load Dump Question --> AeroElectric-List message posted by: "Vincent Welch" OK, I'm almost with you Paul. If I place a transorb (say, the Whackjack) on the alternator side of the B-Lead contactor, doesn't that clamp the entire line from alternator, through contactor, to the bus? If the battery is taken offline accidently isn't the bus still clamped through that transorb? If the B-Lead contactor opens due to the OVP trip won't the bus voltage be stabilized by the battery? If all of these things are true, why do we need a second transorb on the bus side? If I do need a second transorb on the bus side, is another Whackjack acceptable or should I use something else? If so, what? Vince >From: "Paul Messinger" >Reply-To: aeroelectric-list@matronics.com >To: >Subject: Re: AeroElectric-List: Load Dump Question >Date: Sat, 22 Jan 2005 14:26:53 -0800 > >--> AeroElectric-List message posted by: "Paul Messinger" > > >As I recall the original start of this thread was early last year when >there >were failures of Van's rebuilt alternators. Bob and others questioned the >quality of the rebuilt regulator in the Van's alternator. > >Personally I have never seen any real proof of what was the true cause. I >have real trouble believing Van would sell substandard alternators. ALL >standard alternator internal regulators are protected against worst case >load dump. > >Any way You are correct that in the case of a real alternator regulator HI >voltage failure, the only solution is to cut the "B" lead and "so what" if >that causes an isolated load dump that the alternator cannot take. > >However if the alternator is working fine and the battery is disconnected >the resulting load dump is distributed to the bus and can cause harm >depending on what is on the bus and how big the load dump is. > >There are a couple of solutions to this. First a transorb big enough to >clamp the load dump hi voltage. This has nothing directly to do with any >OVP >device present. > >However Bob's crow bar OVP will trigger with the above load dump and this >results in the hi current during its operation that some of us object to. A >simple addition of a small value series resistor fixes that. > >If the load dump is a result of the "B" lead opening the load dump issue is >contained to the alternator where you may or may not damage the alternator >internal regulator. A transorb on the alternator side of the "B" lead >contactor will protect the alternator if the regulator is not up to the >task. This is a second transorb as one needs to be on the Bus side also. > >If the load dump is a result of disconnecting a charging battery the load >dump is delivered to the aircraft bus and potential damage can result to >your avionics. Its likely the OVP will trip but not in time in all cases to >prevent a short hi voltage pulse on the BUS. The OVP takes some time to >start clamping (5-10MS?) and much longer (50-100ms) to disconnect the >alternator thru the "B" lead contactor. Even 5 ms is long with a 60V or >higher pulse on BUS. > >So some of us feel the need for the "Transorb" to keep the BUS voltages >clamped while the OVP can act. The transorb acts not in 5 MS but in 1/2 >pico >second 10,000+ times faster and faster than any damage can start. > >If the failure is a failed hi voltage alternator the transorb clamps the >voltage while the OVP acts. Both arte needed in the safest system. > >If this does not answer your concerns ask more as everyone benefits from >such a "conversation" > >Paul > >----- Original Message ----- >From: "Vincent Welch" >To: >Subject: AeroElectric-List: Load Dump Question > > > > --> AeroElectric-List message posted by: "Vincent Welch" > > > > > Hey guys, I have been watching this "Battle Of The Titans" with great > > interest. I have a question from one a bit lower down the food chain:) > > > > It has always been my understanding that the purpose of the OV circuit >was > > to protect my avionics from a runaway alternator. The alternator or > > regulator has already failed and the voltage is climbing. The crowbar >opens > > the circuit to limit prevent damage to my expensive avionics. The > > alternator/regulator has already failed, its trash, so I open the B-lead > > under load, I get a load dump event. So what? Why do I care about >trying > > to protect the alternator now? > > > > I can understand limiting the crowbar circuit current and adding a >resistor > > sounds like a simple easy solution to that problem. > > > > What am I missing here? Please further educate me. > > > > Vince > > > > > > ________________________________ Message 27 ____________________________________ Time: 06:39:34 PM PST US From: "Dan O'Brien" Subject: AeroElectric-List: Re: Garmin/Microencoder wiring question --> AeroElectric-List message posted by: "Dan O'Brien" >The Garmin wiring diagrams are wrong in this and one other in respect >to the grounding at both ends of the >shields. Do not ground both ends of the shields or the least that will >(could) cause a ground plane loop. I called, and asked Garmin tech guys at >the AOPA convention about the shield grounding at both ends for the GI-106A >obs, and at first I received somewhat blank stares. Then finally got a >definitive NO, do not ground shields at both ends. So the manual is incorrect? Well, that leaves me in a lurch, since if the shield is only supposed to be grounded at one end, which end? Guess I'll call Garmin. In the past, they've not been very helpful, as the unit is "supposed to be wired by an avionics supplier." (This is unlike the old UPS, which was great in supporting the experimental market. Of course, USP is now Garmin too.) We'll see. ________________________________ Message 28 ____________________________________ Time: 06:44:28 PM PST US From: "Dan O'Brien" Subject: AeroElectric-List: Re: General Wiring Question --> AeroElectric-List message posted by: "Dan O'Brien" >The assumption is (by Garmin) is the 430 tray is connected to the airframe >through mounting screws, and the ground terminals (I found the purpose of >those at AOPA convention) is connected to the tray, and the tray to the >airframe. At least that's the way mine is and it works. On a composite like my Lancair, the mounting screws will not ground the tray. Is one supposed to run a wire from the ground stud on the radio case to the ground bus? There is no mention of this in either the Garmin 430 or UPS SL30 manuals. ________________________________ Message 29 ____________________________________ Time: 07:04:48 PM PST US From: "Wayne Sweet" Subject: Re: AeroElectric-List: Re: Garmin/Microencoder wiring question --> AeroElectric-List message posted by: "Wayne Sweet" Dan, I told them it was an experimental airplane and I was the builder. They willingly answered my questions. Are you calling Garmin or the avionics retail store you bought it from?? I would ground the shields for the encoder wiring at the GND430, on the shield ground connector. Wayne ----- Original Message ----- From: "Dan O'Brien" Subject: AeroElectric-List: Re: Garmin/Microencoder wiring question > --> AeroElectric-List message posted by: "Dan O'Brien" > > > >The Garmin wiring diagrams are wrong in this and one other in respect > >to the grounding at both ends of the > >shields. Do not ground both ends of the shields or the least that will > >(could) cause a ground plane loop. I called, and asked Garmin tech guys > >at > >the AOPA convention about the shield grounding at both ends for the > >GI-106A > >obs, and at first I received somewhat blank stares. Then finally got a > >definitive NO, do not ground shields at both ends. > > So the manual is incorrect? Well, that leaves me in a lurch, since if the > shield > is only supposed to be grounded at one end, which end? Guess I'll call > Garmin. > In the past, they've not been very helpful, as the unit is "supposed to be > wired by an avionics supplier." (This is unlike the old UPS, which was > great > in supporting the experimental market. Of course, USP is now Garmin too.) > We'll see. > > > I am using the free version of SPAMfighter for private users. It has removed 698 spam emails to date. Paying users do not have this message in their emails. Try www.SPAMfighter.com for free now! ________________________________ Message 30 ____________________________________ Time: 07:20:33 PM PST US From: "Wayne Sweet" Subject: Re: AeroElectric-List: Re: General Wiring Question --> AeroElectric-List message posted by: "Wayne Sweet" OK, I may be wrong. The 430 does have a ground wire for both the COM and GPS power supplies (connectors P4002 and P4001). Check with a multimeter (ohms) to see if the ground terminals, that funny looking thing on the back of the tray, Fig F-6 which identifies it as Shield Grounds, and one of the ground wires have continuity when the 430 is plugged in. If not, then I would guess you need to run a ground wire from the tray to you aircraft ground bus. Let us know what you find out. Wayne ----- Original Message ----- From: "Dan O'Brien" Subject: AeroElectric-List: Re: General Wiring Question > --> AeroElectric-List message posted by: "Dan O'Brien" > > > >The assumption is (by Garmin) is the 430 tray is connected to the > >airframe > >through mounting screws, and the ground terminals (I found the purpose of > >those at AOPA convention) is connected to the tray, and the tray to the > >airframe. At least that's the way mine is and it works. > > On a composite like my Lancair, the mounting screws will not ground the > tray. > Is one supposed to run a wire from the ground stud > on the radio case to the ground bus? There is no mention of this > in either the Garmin 430 or UPS SL30 manuals. > > > I am using the free version of SPAMfighter for private users. It has removed 698 spam emails to date. Paying users do not have this message in their emails. Try www.SPAMfighter.com for free now!