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Discussion Starter · #1 ·
I'm not sure what model tractor I have - my guess is a 1955 Torque Amplifier 300 - but serial number is 17372-SJ. Attached is image of existing alternator. tractor is 12v POSITIVE ground.

Need a part number or an alternative that will work.

Thanks
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I'm not sure what model tractor I have - my guess is a 1955 Torque Amplifier 300 - but serial number is 17372-SJ. Attached is image of existing alternator. tractor is 12v POSITIVE ground.

Need a part number or an alternative that will work.

Thanks View attachment 22435
I could be wrong but the picture sure looks like a generator vice alternator. It looks like somebody put a 12 volt generator on it. It was a common way to convert to 12 volt back in the day. They are not hard to rebuild, brushes and bushings as long as the armature and field windings are good. Also, check you voltage regulator.
 

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Discussion Starter · #3 ·
I actually found an original aftermarket one at AutoZone made by Wilsons. But at a price ----- $316!
I could be wrong but the picture sure looks like a generator vice alternator. It looks like somebody put a 12 volt generator on it. It was a common way to convert to 12 volt back in the day. They are not hard to rebuild, brushes and bushings as long as the armature and field windings are good. Also, check you voltage regulator.
So was my tractor originally 6 volt? Is that what you are saying? The AutoZone parts catalog said this unit was original. After 66 years I though rebuilding probably not worth it. I'll look at the regulator too. Thanks
 

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According to Tractordata.com the IH 300 was a 6V positive ground when built. TractorData.com International Harvester 300 tractor information
As for rebuildiung, old iron is good iron! I have rebuild a few generators. Not hard to do but if you don't feel up to it any decent auto starter/alternator should be able to do it for a decent price. e

One thing you can do is to remove the cover band and check the brushes, one may be stuck or the springs may be rusted and weak.
 

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I'd put a 7127 rebuilt Delco alternator on it, change to negative ground, add a ballast resistor in front of the coil if it is a 6 volt one, and have a much more modern charging system. Dont forget a 12 volt battery too.
 

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I'm not sure what model tractor I have - my guess is a 1955 Torque Amplifier 300 - but serial number is 17372-SJ. Attached is image of existing alternator. tractor is 12v POSITIVE ground.

Need a part number or an alternative that will work.

Thanks View attachment 22435
that is definitely a generator like mine. If you convert to alternator you have to reverse the polarity cuz alternators are negative ground. You have to reverse the wires on the ammeter and battery and I think the coil, those two little wires.
 

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Discussion Starter · #7 ·
UPDATE. Learning more here and yes this is a 12v positive ground starter/generator. I'm looking inside tomorrow to see if I can fix it, but have a new one. Having dished out the cash I'm wondering as the starter works fine if it is just the voltage regulator?
 

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UPDATE. Learning more here and yes this is a 12v positive ground starter/generator. I'm looking inside tomorrow to see if I can fix it, but have a new one. Having dished out the cash I'm wondering as the starter works fine if it is just the voltage regulator?
Question. How many caps are on your battery? If there are 3 the system is 6 volt, if there are 6 then it is 12 volt. The easiest way I know to check the generator is to disconnect the wires at the generator (effectively disconnecting the regulator) and start the tractor. Use a voltmeter to check if there is any output from the generator (check both terminals). The output should be above 6 volts or 12 volts depending on your system If there is output it should increase in voltage with an increase in RPMs. If it does then it is likely your voltage regulator or wiring. The regulator sends feedback to the generator to regulate the voltage output regardless of engine RPM.
 

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Discussion Starter · #9 ·
Question. How many caps are on your battery? If there are 3 the system is 6 volt, if there are 6 then it is 12 volt. The easiest way I know to check the generator is to disconnect the wires at the generator (effectively disconnecting the regulator) and start the tractor. Use a voltmeter to check if there is any output from the generator (check both terminals). The output should be above 6 volts or 12 volts depending on your system If there is output it should increase in voltage with an increase in RPMs. If it does then it is likely your voltage regulator or wiring. The regulator sends feedback to the generator to regulate the voltage output regardless of engine RPM.
The battery is definitely 12v. It's a regular sealed auto battery. When running I can not measure any output from the generator terminals and also there is no increased voltage across the battery terminals compared to when tractor is not running.
 

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Have you polarized the generator? There is plenty of info on the net about how to do it.
 

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I would try flashing the field on the old generator before replacing it.
Sometimes they just need a jumpstart after sitting a bit or even just replacing the battery.
 
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