PDA

View Full Version : amp meter



Tom T.
03-08-2008, 10:00 PM
Is the amp meter supposed to be hooked up with a line and load terminal? In other words, can they be hooked up backwards? Mine is showing a discharge but I am almost certain the battery was not in a fully charged state when we started the engine today for the first time in a year and a half. It went right strait to discharge. :confused:

12611
03-08-2008, 10:55 PM
HI, they can be hooked up backwards and would indicate backwards.
Doug.

Gilbert Pierce
03-08-2008, 10:57 PM
Yes they can be hooked up backwards and it will show discharge when in fact it is charging.
Put a voltmeter on the battery and read the voltage. Start the engine. If the battery voltage increases the battery is charging. If the battery voltage stays the same it is not charging. You have to rev the engine up a little to get it to charge if you have a generator.

Tom T.
03-09-2008, 12:21 AM
Man, this is what I wanted to hear!!! I'll swap them around tomarrow and check it again the next time we run it. It might be a few days, as I also have an oil line fitting that is leaking, and we'll fix it first.
Thanks for the instant reply.

Homer Landreth
03-09-2008, 01:00 AM
Whoa ! Tom: Don't go just switching wires around. That is a first class way to get a maximum result "smoke check". Also, in a previous post you said you put in an alternator, This post said:

Yes, that is what I have on my tripacer and I would be more than happy to send you a copy of my 337. Send me a private email with your mailing address and I will try and get it off to you before the weekend.
I am not sure of those numbers, mine just says a 40 amp alternator from a piper cherokee.

You should not have to rev the engine very high to get a charge. If you are getting a discharge at less than about 1300 RPM, you may very well have the wiring incorrect, especially the wiring to the alternator field. I would be interested in seeing your schematic, however from all that I can think of relative to an alternator modification, there would have been nothing required to do that would require you to switch your ammeter wiring to get it to work correctly. I would suggest that you not run it any more and go wire to wire and verify your hook up. Send me your schematic, and I would be glad to see if I can coach you through some troubleshooting.

Tom T.
03-09-2008, 02:48 AM
:( Now dog gonnit Homer, I was just happier than a pig in sh%& when all I was needing was to swap the 2 wires.
I aint smart enough to draw out the scematic and send it to you. But, under the circumstances I am going to try, and I will send it to your private email, or try to.
Iam on it,
Thanks Homer

Homer Landreth
03-09-2008, 09:48 AM
Hi Tom; Your 337 should of had a schematic on it. If it didn't, go get the I/A who signed it off and tell him he owes you proper documentation of the modification.

Tom T.
03-09-2008, 11:38 AM
Nope, all it says is what they used to install it in accordance to piper pa28 service manual, pn 753 586 sec. XI and conforms to wiring diagram figure 11-54.

The owner at that time was, Nolfi, Eugene V. and dated 12/9/83 and the mechanic was George Lewis from Indio, Ca.

I got it hooked up like it was before I tore everything apart except with one minor little detail, it dont work!

Homer Landreth
03-09-2008, 11:49 AM
I'll bet Krispy Kremes and Starbucks (maybe Seattles Best instead) that the wiring doesn't come close to conforming to Figure 11-54 in the Pa28 manual. Anyway, drop me a line and let me know what I can do to help.

Tom T.
03-09-2008, 11:53 AM
I sent you a private email last night, hopefully the picture comes thru.

Gilbert Pierce
03-09-2008, 11:55 AM
Like I said, step one, put a voltmeter across the battery. Record the voltage. Start the engine. If the voltage increases and your amp meter shows discharge your meter is more then likely reversed.
You have already run it so you aren't likely to do any more damage. If it is not charging-i.e. the battery voltage does not increase with the engine running then step two is to follow Homers advice.
Do the easy, non evasive stuff first.

Tom T.
03-09-2008, 12:05 PM
Like I said, step one, put a voltmeter across the battery. Record the voltage. Start the engine. If the voltage increases and your amp meter shows discharge your meter is more then likely reversed.
You have already run it so you aren't likely to do any more damage. If it is not charging-i.e. the battery voltage does not increase with the engine running then step two is to follow Homers advice.
Do the easy, non evasive stuff first.
Hopefully it will be ready to run again by the end of the week. Need to replace an oil line fitting first, and then I will do those checks. I have a little cig. plug in volt meter that works quite niffty for this. I wish I would have had it plugged in when we ran the engine!

Gilbert Pierce
03-09-2008, 12:40 PM
Your voltmeter needs to be sensitive enough read a small increase. Depending on the state of your battery the reading my only jump 0.3 to 0.5 volts when (if) the alternator charging. The voltmeter with the little colored lites won't do.

Tom T.
03-09-2008, 09:17 PM
Yea, I am fairly well equipped for testing power, all the way to 13200 volts.
IBEW Retired after 37 years. That little toy tester has .5 volt increments but I also have a Fluke in my hanger just for the plane stuff!
Those little colored lite types are no good for anything, but you can check hi voltage with them! Dont touch any leads to the conductor, hold your thumb on one lead, swing the free lead close to the high voltage and the inductance will let cha know when the lite blinks. A last resort!!! NOT RECOMMENDED!!

Hillbilly
03-09-2008, 10:49 PM
Whoa ! Tom: Don't go just switching wires around. That is a first class way to get a maximum result "smoke check".

Homer about two weeks ago my charger for the makita cordless drill got plugged into a 220 outlet, (an old style twistloc, a two prong houseplug will "fit") I got one of them "smoke checks" you speak of... :mad:

Gilbert Pierce
03-09-2008, 10:53 PM
Tom
Use the Fluke

Homer Landreth
03-10-2008, 08:36 AM
Everyone needs to understand the absolute simplicity of electronic components. Simply stated, all electronic components in electronic devices internally contain smoke. That is how they operate. Therefore if you do anything to them to let the smoke out, they will not work any more. :D

Hillbilly
03-10-2008, 09:08 AM
yep, we call it the "magic smoke"...

SandyM
03-10-2008, 09:31 AM
My wife figured out how to plug her hair dryer directly into an outlet in New Zealand (220v) when we were there. Worked REAL GOOD for about 20 seconds! :eek: Luckily the smoke test you speak of didn't include her hair. :D

Hillbilly
03-10-2008, 03:58 PM
My wife figured out how to plug her hair dryer directly into an outlet in New Zealand (220v) when we were there. Worked REAL GOOD for about 20 seconds! :eek: Luckily the smoke test you speak of didn't include her hair. :D

Yea most of the world is on 220 house current, in S.E. Asia they have a whole bunch of different outlets, some like ours, some big round three prongs etc...its a mess. Gotta have adapters for the adapters.