---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 09/08/07: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:13 AM - Re: How to check an alternator?? (Matt Reeves) 2. 05:23 AM - Re: Transponder constantly replies (Thermos) 3. 07:32 AM - Re: How to check an alternator?? (Robert L. Nuckolls, III) 4. 01:47 PM - New Realtime Spell Checker Added To Matronics Forums! (Matt Dralle) 5. 02:34 PM - Re: How to check an alternator?? (Peter Harris) ________________________________ Message 1 _____________________________________ Time: 05:13:40 AM PST US From: Matt Reeves Subject: Re: AeroElectric-List: How to check an alternator?? Okay, I wired my ammeter backwards and here's what happens. I start the plane and the ammeter is on the positive side slightly. I turn on NAV lights, strobe lights, landing lights and the ammeter goes MORE positive and stays there and the voltage goes from 15 to right around 14. Turn off everything, the voltage goes to just under 15 and ammeter goes to zero. So I don't think my ammeter was wired backwards. It appears my alternator is charging normally but I think my ammeter needs to see a therapist. Matt "Robert L. Nuckolls, III" wrote: At 04:30 AM 9/2/2007 -0700, you wrote: >Hi Bob !! > > >Thanks for the help and suggestions !! I really appreciate you and all I >learn from you. > >So, I did exactly as you said, and you are 100% correct. I left on a >bunch of stuff for about 10 minutes, then started the plane and >immediately noticed the ammeter was slightly on the negative side, maybe >reading about 4 negative amps. The voltage read just under 15 volts - >say 14.7 the whole time and stays there but within about 3 minutes, the >ammeter came back up to zero and stayed there. > >I wired the ammeter and external shunt as per Van's Aircraft instructions >and my brother Danny (which you've all heard from many times) says there >are 2 other ways (according to Dynon) to wire the ammeter which I might do. > >I'm not sure of the best or correct way to wire the ammeter but at least >now I know my alternator is working perfectly and THAT makes me happy. > >Maybe I should leave it alone since I now know exactly what it's reading. > >Thanks for your input and suggestions. Sounds like your ammeter is a bit big for the job and it may be wired backwards too. Normally, one expects to see a STRONG + reading while the battery is being replenished, a near ZERO reading while the alternator is carrying ships loads and the battery is charged, and a STRONG - reading when the alternator is off and everything thing is turned on. Your "slightly negative" observation while charging the battery tells me it is too small and wired backwards. Bob . . . --------------------------------- Boardwalk for $500? In 2007? Ha! ________________________________ Message 2 _____________________________________ Time: 05:23:18 AM PST US Subject: AeroElectric-List: Re: Transponder constantly replies From: "Thermos" Transponders reply to a pair of interrogation pulses spaced 8 microseconds apart. Anything that can generate that RF pulses with that spacing, like Bob's drill or a piece of computer equipment, could theoretically trigger a reply. It seems unlikely that a loose connection could do that consistently enough to keep your reply light on, but stranger things have happened. It may be that your transponder is just receiving a lot of interrogations - ATC radars, military radars, TCAS - especially if you're flying in/around a busy terminal area. If you can check with someone else flying close by at the same time and altitude, their transponder should be doing the same thing as yours if both boxes are working correctly. Hope this helps... Dave Read this topic online here: http://forums.matronics.com/viewtopic.php?p=133380#133380 ________________________________ Message 3 _____________________________________ Time: 07:32:02 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: How to check an alternator?? At 05:12 AM 9/8/2007 -0700, you wrote: >Okay, I wired my ammeter backwards and here's what happens. > >I start the plane and the ammeter is on the positive side slightly. > >I turn on NAV lights, strobe lights, landing lights and the ammeter goes >MORE positive and stays there and the voltage goes from 15 to right around >14. Turn off everything, the voltage goes to just under 15 and ammeter >goes to zero. > >So I don't think my ammeter was wired backwards. > >It appears my alternator is charging normally but I think my ammeter needs >to see a therapist. > >Matt We need to see the schematic as to how your ammeter is wired. The classic battery ammeter is wired between the bus and the battery and all loads run from the bus side, all power is fed to the battery (via alternator) from the bus side. Hence, the minus-zero-plus ammeter is a indicator of rate of discharge/charge for the battery. Alternator off and all things on, the ammeter should show not slightly, but significant discharge left of zero. Alternator on after starting and then recharging a taxed battery, the ammeter should show a significant charge of the battery that subsides with time. You've consistently used "slightly" to describe ammeter movement and you've yet to give us words that suggest that the ammeter is in a position to properly sense and display the charge/discharge conditions cited above. This gives rise to two, possibly concurrent conditions: (1) the ammeter is the wrong size . . . expects to see much larger currents than your system experiences such that all indications are "slight" versus "significant". (2) the ammeter may not be properly positioned in the system. You need to acquire specifications for the ammeter and deduce whether or not it is wired per the instructions that came with it. Is the ammeter "calibrated"? I.e., does it have the word AMPS on the front? What is the full scale value on the face? -30 to +30? -60 to +60? Does this device have a shunt or just two fat wires that carry all the current to be monitored? Bob . . . ________________________________ Message 4 _____________________________________ Time: 01:47:31 PM PST US From: Matt Dralle Subject: AeroElectric-List: New Realtime Spell Checker Added To Matronics Forums! Dear Listers, Today 9/8/2007 I have added a new real-time spell checker function to all of the BBS Forums at Matronics. When you reply or create a new message on the Forums, you will notice that misspelled words will be high-lighted in yellow. If you left-click on the word, you will be prompted with a drop-down list of suggested spellings. http://forums.matronics.com Enjoy! Matt Dralle Matornics Email List and Forum Administrator ________________________________ Message 5 _____________________________________ Time: 02:34:56 PM PST US From: "Peter Harris" Subject: RE: AeroElectric-List: How to check an alternator?? Matt MORE positive under more load = ammeter is wired backwards. Peter _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt Reeves Sent: Saturday, 8 September 2007 10:12 PM Subject: Re: AeroElectric-List: How to check an alternator?? Okay, I wired my ammeter backwards and here's what happens. I start the plane and the ammeter is on the positive side slightly. I turn on NAV lights, strobe lights, landing lights and the ammeter goes MORE positive and stays there and the voltage goes from 15 to right around 14. Turn off everything, the voltage goes to just under 15 and ammeter goes to zero. So I don't think my ammeter was wired backwards. It appears my alternator is charging normally but I think my ammeter needs to see a therapist. Matt "Robert L. Nuckolls, III" wrote: At 04:30 AM 9/2/2007 -0700, you wrote: >Hi Bob !! > > >Thanks for the help and suggestions !! I really appreciate you and all I >learn from you. > >So, I did exactly as you said, and you are 100% correct. I left on a >bunch of stuff for about 10 minutes, then started the plane and >immediately noticed the ammeter was slightly on the negative side, maybe >reading about 4 negative amps. The voltage read just under 15 volts - >say 14.7 the whole time and stays there but within about 3 minutes, the >ammeter came back up to zero and stayed there. > >I wired the ammeter and external shunt as per Van's Aircraft instructions >and my brother Danny (which you've all heard from many times) says there >are 2 other ways (according to Dynon) to wire the ammeter which I might do. > >I'm not sure of the best or correct way to wire the ammeter ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.