Re: Generator question...


[Follow Ups] [Post Followup] [Dodge Power Wagon Forum]


Posted by David Sherman on Sunday, August 07, 2005 at 6:33PM :

In Reply to: Generator question... posted by Turtleherder on Sunday, August 07, 2005 at 2:17PM :

I'd test it on the vehicle, because to bench test it you have to jerry-rig some kind of motor and belt system to drive it. The problems with generators are usually not subtle -- either it works or it doesn't. I usually just test generators and alternators by putting a voltmeter on the battery and seeing if the voltage goes up appreciably (to 14 volts) when the engine RPM is increased. Turn on the headlights and heater fan if you want a little more load. If it doesn't go up, then jump the field terminal straight to the ungrounded end of the battery and see what the voltage is. If the voltage goes way up then, the regulator needs work. If it still doesn't go up, poke around for bad connections, and if all looks good, the generator's probably bad. Brushes are easy to replace, but anything else should go to a competent shop.

If you don't have a vehicle to test it on, you'd have to simulate one to do a meaningful bench test -- devise some way to mount it and make it spin, attach a regulator and a battery, and make some kind of load. If you can get your hands on an old miltary "low voltage test set", it will have pretty much everything you need on the electrical end -- an adjustable load, a field reostat, amp and volt meters, and assorted switches and cables.

Without making some sort of test jig, however, the best you can probably do is take it apart, check the brushes and commutator for wear, and look the windings over for obvious shorts, cuts, or burned parts. If it isn't visually obvious, you'll never detect a shorted winding in either the armature or the field with a normal multi-meter -- the resistance is just too low. You can check for opens, and for shorts from the winding to the frame, but that's it.



Follow Ups:



Post a Followup

Name:
E-Mail:
Subject:
Message:
Optional Link
URL:
Title:
Optional Image Link
URL:


This board is powered by the Mr. Fong Device from Cyberarmy.com