Testing twin alternators

[mtompson]

Hi all
With engine running and testing the voltage off the back of each alternator, can I tell if they are both out putting what I read, or if one was not charging would it still read the overall system voltage?
Is the only way to be sure, remove belt from each in turn?
Cheers
Mark

[Neptune's Gear]

Alternators produce amps. Put a clamp meter on the output cable, and read the amps. That will tell you the output of each alt. If you really want volts, then you will have to disable one at a time - belt off or field off. The Voltage level is set by the regulator...

[GordMay]

First, test voltage /w alternator not running.
Then, test /w alt's running. There should be a significant increase in voltage when running.

[mtompson]

Thanks guys, yes I need to get one of those clamp meters, in the meanwhile I guess to be sure I’ll have to take the belts off, which is a load more hassle, maybe I’ll try and borrow a clamp meter until I have the funds! Cheers

[smac999]

if they both go to the same battery. then if one is working and one is not. you will still get a high voltage on both because they connect to same spot. if they go to different batteries. then the voltage would only go up on one. assuming no ACR / VSR / or battery swtich on parallel

the best way would be with a clamp on amp meter.

note most alts don't do much at idle and need to be reved.

[mtompson]

Got it, thanks everyone.