Alternator part

[Pzkw88]

I'm wondering what this part is and what does it do?

 

[cucvrus]

Is it inside the alternator?

 

[scottladdy]

If it's this then it is an important part of the alternator. It is a wirewound resistor.

https://www.aspwholesale.com/resistor-dr-p2096.html

 

[Pzkw88]

If it's this then it is an important part of the alternator. It is a wirewound resistor.

https://www.aspwholesale.com/resistor-dr-p2096.html

Yes it's inside the alternator and that is the part. I bought an alternator off eBay that was said to be an isolated ground. When I hooked it up the battery sparked horribly and almost fried a battery wire. I took it back off and opened it up and noticed this part missing?!!! I have since got a rebuild kit that includes that part and installed it. I'm wondering if that will fix the problem of the battery cable sparking when I hook it up? I'm pretty new at alternators so any insight is appreciated.

 

[Paycheck]

If it's in the original it might be important

 

[TGP (IL)]

That part has nothing to do with the isolated ground.
Some Alt. have that resistor some don't.

The isolated ground Alt have plastic washers insolating the voltage regulator, and other
Internal components from the case.
Tom

 

[cucvrus]

That is what confused me. I never seen one before on a CUCV. I don't rebuild my own alternators or starters. I have taken them apart already. I tapped into a few to install hour meters. Thank you for the clarity in identifying the part.

 

[scottladdy]

Don't have a lot of time but let's get you started. And welcome to the site and the MV hobby.

1. Most alternators are grounded (run the negative side of the DC output) through the frame of the alternator directly into the engine block or chassis of the vehicle.
2. Since the CUCV is designed to have a 24V starter and 24V stepped down to 12V feed to the glowplugs they have two batteries connected in series. They also have two 12V alternators connected in series. Connecting in series can be visualized like stacking one on top of the other, positive of the first connected to negative of the second. This essentially doubles the voltage producing the 24V.
3. In order for the system to operate properly and not produce a light show, the negative output on the second (right or passenger) alternator MUST be isolated from the frame of the alternator (the ground). It is optional on the first or left hand. The military standardized on one type to simplify maintenance and spares management.
4. Isolation of the negative output is accomplished by adding a negative terminal to the back of the alternator, and then ensuring that this negative output has electrical insulators (fiber or plastic washers, sleeves, etc) that prevent contact with the frame.
5. Having the negative output terminal is not sufficient to ensure the alternator is properly isolated. You should ALWAYS check for continuity between the negative post and the frame of the alternator before installing on the passenger side. If it is NOT properly isolated you will get a light show.

There may now be damage to the internals of the alternator. The part above is a wirewound resistor which I would not run without. Swapping an alternator is relatively easy. If you are mechanically inclined and sufficiently detail oriented (patient enough to follow directions one step at a time) you can rebuild your original alternator. Plenty of threads on this site detailing how to do it. I would suggest returning the replacement you received under warranty since it was not properly an isolated ground.

Hope that helps and all the best!

 

[Tow4]

I'm wondering what this part is and what does it do?

It's a resistor. As noted above, some alternators have them, some don't. Here's a link to my alternator rebuild thread so you can see the insulators that are used in an isolated ground alternator.

http://www.steelsoldiers.com/showthr...rnator-Rebuild

 

[Pzkw88]

Thanks for the great replies. I appreciate that, because I like learning more about the charging system.