ampmeter seems shot ...12 v conversion?

realolman · Aug 22, 2012

My 300 u has an uncompleted 12 v conversion. I decided that I think I'm just gonna rewire the whole thing. I took the alternator to the local shop and they put bearings in it and tested it. Its a Delco CS130 and supposed to be able to output ... I don't remember ...80+ amps. Now I know the engine doesn't turn all that fast, but I assume this alternator is a good deal hotter than the 6 v generator.

I took it home and hooked it back up and it didn't work. I ran a wire straight to the battery and it works, so something is wrong in the wiring. The ammeter hasn't worked since I got it and it seems to be "pegged" ...I imagine that's probably where the charging trouble lies.

I think if I installed a voltmeter, I should probably install another fuse. I think the only fuse in the system is in the lights. I think the voltmeter would probably be more useful, and although I am not a correct police (by a long shot) ...I would like to get something that looks like it belongs.

I have been thinking and I believe a volt meter would be more useful anyway... but if I did decide to reinstall an ammeter, would the output of the alternator be enough higher to cook an 'original" type ammeter?

oldtanker · Aug 22, 2012

(quoted from post at 15:21:24 08/22/12) My 300 u has an uncompleted 12 v conversion. I decided that I think I'm just gonna rewire the whole thing. I took the alternator to the local shop and they put bearings in it and tested it. Its a CS130 and supposed to be able to output ... I don't remember ...80+ amps. Now I know the engine doesn't turn all that fast, but I assume this alternator is a good deal hotter than the 6 v generator.

I took it home and hooked it back up and it didn't work. I ran a wire straight to the battery and it works, so something is wrong in the wiring. The ammeter hasn't worked since I got it and it seems to be "pegged" ...I imagine that's probably where the trouble lies.

I think if I installed a voltmeter, I should probably install another fuse. I think the only fuse in the system is in the lights. I think the voltmeter would probably be more useful, and although I am not a correct police (by a long shot) ...I would like to get something that looks like it belongs.
If you have a 30 ampmeter and are running a 60 amp alternator yes you can mess up the ampmeter. Any standard anolog battery gauge should work if you want to go that way or any 60 AMP or larger meter would work too.

Rick
I have been thinking and I believe a volt meter would be more useful anyway... but if I did decide to reinstall an ammeter, would the output of the alternator be enough higher to cook an 'original" type ammeter?

Dave_Id · Aug 22, 2012

Try switching over the wires on the amp meter. A six volt system used a positive ground, and I assume you switch over to negative ground with the alternator, but forgot to switch over the ampmeter. I did the same thing when I switched over my M.

realolman · Aug 22, 2012

(quoted from post at 15:48:11 08/22/12) Try switching over the wires on the amp meter. A six volt system used a positive ground, and I assume you switch over to negative ground with the alternator, but forgot to switch over the ampmeter. I did the same thing when I switched over my M.

Thanks... I actually never thought about that. This conversion was already done before I bought the tractor. I took the ampmeter apart ... there is practically nothing in there.

The posts to which the wires connect are connected to a piece of aluminum that is bent and routed down around I guess a magnet, that rotates on a little shaft allowing the magnet and attached pointer to rotate... no connection.

The aluminum is intact so it should have charged, but it didn't, I lubed the shaft a little with some wd 40, put it back together and hooked up a couple wires and touched it to the battery posts ... in both directions ..... nuthin'

durn

rustred · Aug 22, 2012

to see if the ampmeter is working when off you need to have pos. post disconnected from batt. and touch one post to the pos. on batt. and the other post to the cable. it will show charge if tractor is chargeing. but you need to do this on a tractor that has a working charging system .
and if the ampmeter is backwards on tractor it will show discharge. it will not cause a no charge situation if the ampmeter is good.

John G. Hasler · Aug 22, 2012

> The posts to which the wires connect are
> connected to a piece of aluminum that is bent
> and routed down around I guess a magnet, that
> rotates on a little shaft allowing the magnet
> and attached pointer to rotate...

Yes, that"s how an ammeter works. The magnetic field created by the current through the bit of aluminum exerts torque on the magnet.

> ...no connection.

What do you mean by that?

> ...hooked up a couple wires and
> touched it to the battery posts...

You connected one terminal of the ammeter directly to the battery negative post and the other directly to the positive? If the meter wasn"t fried before it is now.

Janicholson · Aug 22, 2012

That alternator will fry an original IH amp meter.
The use of a volt meter is OK, and between the alternator, and the volt meter, originality is not happening. A volt meter can be found that has the same face character and size, but the needle and markings will be different. There should be a fusable link in the main heavy wire from the alternator to the starter switch "battery terminal". The fuse link should be 85 amps or so to protect the alternator while allowing it to operate fully without blowing the fuse.
Operating the volt meter can be as simple as just hooking it to the big alt wire on its + side, and grounding the other side. It will be on all the time, but they draw very little current, and are commonly left on. The other way is to switch it on with the ignition, (either way works) If an amp meter is used, it should be + or - 100 amps to allow full scale readings.
Charge voltage should be 14.2 to 14.7 volts at mid RPM. Jim

realolman · Aug 23, 2012

(quoted from post at 17:35:54 08/22/12) > The posts to which the wires connect are
> connected to a piece of aluminum that is bent
> and routed down around I guess a magnet, that
> rotates on a little shaft allowing the magnet
> and attached pointer to rotate...

Yes, that"s how an ammeter works. The magnetic field created by the current through the bit of aluminum exerts torque on the magnet.

I did not know what was in there before I opened it up. I do now. I had often heard that a bit of the charging current was shunted off to the ammeter. it is not. The whole current flows thru the whole meter.

> ...no connection.

What do you mean by that?

I meant that the current on the charging conductor goes straight thru the ammeter on the piece of aluminum and there is no connection (except for the magnetic field ) to the needle

> ...hooked up a couple wires and
> touched it to the battery posts...

You connected one terminal of the ammeter directly to the battery negative post and the other directly to the positive? If the meter wasn"t fried before it is now.

And why would that be?

gene bender · Aug 23, 2012

80 amp to replace a system that was built for 15 no wonder the amp ga gets hot

John G. Hasler · Aug 23, 2012

> And why would that be?

Because it is designed to carry the entire charging current the ammeter has very little resistance. This means that if you connect it across the battery an extremely large current will flow through it, much larger than it was designed for. This is likely to melt that bit of aluminumand/or do other damage.

mkirsch · Aug 23, 2012

(quoted from post at 03:04:05 08/23/12)

You connected one terminal of the ammeter directly to the battery negative post and the other directly to the positive? If the meter wasn"t fried before it is now.

Click to expand...

And why would that be?

Because a direct connection to the battery would shoot 1000's of Amps through the meter, way more than it was designed to handle.

Is the needle stuck even with nothing connected? If so the meter is shot, kaput, done. Replace it.

realolman · Aug 23, 2012

(quoted from post at 05:07:47 08/23/12) > And why would that be?

Because it is designed to carry the entire charging current the ammeter has very little resistance. This means that if you connect it across the battery an extremely large current will flow through it, much larger than it was designed for. This is likely to melt that bit of aluminumand/or do other damage.

I [b:92144724a0]touched[/b:92144724a0] it to the battery I didn't hook it to the battery and let it there. The needle never moved. It never melted anything.

You connected one terminal of the ammeter directly to the battery negative post and the other directly to the positive? If the meter wasn"t fried before it is now.

I think touching it to the battery momentarily was a perfectly reasonable thing to do.

tn terry t · Aug 23, 2012

(quoted from post at 16:33:40 08/23/12)

(quoted from post at 05:07:47 08/23/12) > And why would that be?

Because it is designed to carry the entire charging current the ammeter has very little resistance. This means that if you connect it across the battery an extremely large current will flow through it, much larger than it was designed for. This is likely to melt that bit of aluminumand/or do other damage.

Click to expand...

I [b:1ce31eb065]touched[/b:1ce31eb065] it to the battery I didn't hook it to the battery and let it there. The needle never moved. It never melted anything.

You connected one terminal of the ammeter directly to the battery negative post and the other directly to the positive? If the meter wasn"t fried before it is now.

Click to expand...

I think touching it to the battery momentarily was a perfectly reasonable thing to do.

ince you have it all figured out just for kixs and giggles after you get your new amp gauge hook it to the battery and see whats happens

ampmeter seems shot ...12 v conversion?

realolman

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oldtanker

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Dave_Id

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realolman

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rustred

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John G. Hasler

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