[mybad69]

This is probably a really stupid question but how do you check the amps coming from the alternator??? If you check the volts you touch a ground and then the back of the red power cable on the back of the alternator with your voltmeter on ac current?? How do you check the amps if it is possible and what do you turn your voltmeter to read them?????

 

[John_Muha]

Probably the easiest way in to take it down to a local rebuilder and have it checked. You won't be able to do it with your meter.
The output of the alternator changes depending on what it is doing. If the battery is fully charged and everything is off it's only running the engine. It's best to know what the alternator is capable of putting out. What it does at one time or another doesn't really mean anything.
The alternator needs to be loaded so that it puts out its maximum current (amps). The rebuilder has the proper loads and equipment to make the alternator do that.

 

[mybad69]

Thanks for the info, was just wondering how it could be done with the trusty old fluke..I think I'll just leave well enough alone.

 

[Finally]

Originally posted by mybad69:
Thanks for the info, was just wondering how it could be done with the trusty old fluke..I think I'll just leave well enough alone.

Odds are your trusty old Fluke is not capable of handling/measuring that much current. If it were capable the method would be to put it inline, between the alternator and the wire going to the battery. With all the current flowing through the meter. But as John pointed out how do you know when the alt is putting out it's maximum current? Hard to do with the voltage reg and battery hooked up.

 

[wayner]

Clamp on amp meters that have DC capability will measure the amperage, also MAC tools sells little gauges that work similar, but you only have to rest it against the wire to see the amount of amperage, I have 1 for alternators and 1 for checking starter motor draw, although the MAC tools gauges IMHO are not 100 % accurate.
Having said all that, you still will only measure what the alternator is putting out at the time, and not total amperage the alternator is capable of outputting, as allready stated in a previous post.

 

[Herb]

There is a test device with variable load capability is used in some garages to do load testing on alternators. However, this could easily become a "Destructive" test. It's a little like seeing if a light bulb can really stand up to 120v vs the 110v it's been operating at for a year in your house. The results could very well be...NO. Loading up an alternator to see if it can produce full rated amperage requires the same type of "stress" testing. And the results could be the same.

I subscibe to the theory of, "If it ain't broke, don't fix it." If it's meeting the need, what difference does it really make if it's only able to produce 92 amps vs 100?

Just my $.02 worth.

 

[Finally]

Originally posted by Herb:
Besides, this could easily become a "Destructive" stress test. I subscibe to the theory of, "If it ain't broke, don't fix it." If it's meeting the need, what difference does it make if it's only able to produce 92 amps vs 100?

Just my $.02.

Kind of like determining how much to torque a bolt down. Tighten until it snaps then back it off a quarter turn.

 

[Herb]

Yeah, that's what I meant.