Alternator bench testing

[Dano41]

Hi I've taken this off my massey 35 tested it with a volt meter while on the tractor and it was putting out no volts.How can I bench test this type of alternator?There is no make or number on the outside of the alternator how would I know which repair kit to buy?

 

[Phil Tibbetts]

Take it to an auto parts store. Most of them have a tester and will do it free.

 

[Jim.ME]

First you need to identify it. Pictures of it assembled, showing a couple different views, might help people looking at your post. It could be an aftermarket replacement with no ID, so even if it looks like a particular brand, getting parts could be a crap shoot.

A bench test for most is; the alternator gets mounted on a machine, spun, energized, and checked for output. You should have been able to check the same while it was on your tractor.

It looks like you are trying to test individual components. Some more disassembly may be required to test properly, As far as getting a kit; the parts you need may or may not be in a kit, if you find one. It looks like it may have a regulator mounted on it, perhaps it is the regulator that is bad, I doubt that would be in a kit. You could end up with about as much, or more, in parts than an exchange unit costs.

If it was an expensive alternator that would be hard to replace I'd look at rebuilding it (or having an electrical shop do it) but in this case I would just exchange it for another. Or change to a Delco 10SI type and do a bit of rewiring if needed. JMHO

 

[wore out]

It appears to be a Magneti Marelli alternator.

I would check the brushes, if they are not worn out and not making contact it's probably going to be the most cost and time effective to simply replace it.

As an example, DB Electrical (on the 'net) has one for $70. (Item Number: ALU0023)

Check this very site FIRST (YT) and see if they have one, it's always good to support out gracious hosts![/url]

 

[Dano41]

Thank you for replies new one ordered.

 

[Dano41]

Fitted new alternator its still not charging.The small wire to the alternator is reading 12.50 volts and the large wires to alternator are the same.The alternator bulb isn't going out.

 

[shaeff]

Are you using an internally regulated alternator or still using the external voltage regulator?

If you're using an internally regulated, at what RPM is it supposed to excite? (one-wire, self exciting alternators work well on these machines)

 

[Dano41]

(reply to post at 07:49:56 10/14/20)

Its an internally regulated one don't know what rpm's they excite at.