Will welding fry an ammeter on a tractor?

[super55]

I think I know the answer to this but anyways just looking for some confirmation.

I was welding some sway chains on my oliver and forgot to disconnect the battery. Everything seems to work fine and it appears the tractor is still charging. I had ran it several times and it always started right up afterward even in temps in the single digits but I had noticed that immediately after welding the chains that the ammeter sits at dead zero with no fluctuation.

Im really hoping I didn't do a costly mistake and zap my voltage regulator.

 

[rsallen]

Is it an ammeter or voltmeter?
Don't matter I guess, but sounds like you better check your alternator output.

 

[super55]

I did check output from my volt reg to yes the ammeter and its putting out 14-17 volts. So I know its still working just don't know how well. Think I will just buy a replacement ammeter and give it a shot and go from there. Everything seems to be working fine except for the gauge.


Im about 60% sure I zapped it but just looking for some confirmation. I know there are a lot of welders and tractor restorers on here that will say you did a 25 dollar mistake by not disconnecting the batt.

 

[rsallen]

Head scratch'n here trying to remember.
You can get voltage but if you don't have any push (amperage) those volts aren't worth much.
Meaning you can have voltage but no amps.

You need to full field the alternator and check the amperage.

 

[bandaidmd]

If it's putting out 13.6 to 14.7 volts with the lights on it should be fine.

 

[rsallen]

Yeah, a tractor alternator shouldn't need much.
What is it maybe 30 or 40 amps?

 

[Gary Fowler]

I know most folks agree that before welding on any vehicle, you should disconnect the battery ground. That said, I have welded many times on tractors and cars without disconnecting the battery without damaging anything. If you ground directly to the part you are welding on and keep a good connection, you wont likely damage anything, but there is always a chance so it is best to disconnect. Did your welding damage your gauge, possibly or maybe it just has a loose connection. Check your wiring to the gauge. It would seem that if any damage was done it would have been to a diode in the alternator rather than the ammeter.

 

[Zebrafive]

Could the amp meter have fusible link or fuse blown?

 

[super55]

Prior to me welding the ammeter was pushing 30 amps and everything was working great. Gauge was accurately reflecting amps being pushed. I've welded before without any issues and my ground was right next to my work area so when I started it up and the ammeter was not working I was kind of suprised.

The problem I come into is my multimeter is incapable at reading DCa I can only register DCv.

 

[Norm W]

Check the voltage at the battery with the lights on. If the amp meter is fried (or a loose connection) there should be a lower voltage at the battery than at the alternator. The amp meter is in series with the output of the alternator and the battery. If you have a volt meter it is in parallel with the battery. I've never had a problem with alternators as long as the welding ground doesn't cause the welding current to go through it to get to ground. The usual problem is with the "Magic Smoke" in the computers that are in the engine controls. I doubt that you have any of the computer controls on an Oliver.