

| Subject: | Re: Alternator & O2 lights |
| From: | Harvey Chao |
| Date: | 8 Dec 1995 20:34:11 -0800 |
RE>>Alternator & O2 lights on 12/8/95 >My van does this everytime. The lights go off after a certain rpm and >do not come on again. I've heard this is normal and has something to >do with the field voltage in the alternator or some such (someone set >me straight). My interpretation of Steve's input above is: When I start my van the red alternator light remains on until the engine revs climb above idle, either when I "blip" the throttle, or when I accelerate to drive off. (personally, I have a diesel, so there is no "fast idle" when I start a cold engine, idle speed is always the same). Steve is pretty close to the mark as I understand the alternator/regulator circuits. These are "self exciting" alternators, depending upon residual magnetic field storage to "bootstrap" the device into the generation of electricty when you first start them rotating. I think (gimme so slack, it has been almost 30 years since I took that course (that I hated) in rotating machinery) that the output builds up with rpm until it can generate enought voltage to energize it's own field windings, and then the regulator can kick in and do it's thing. Anyone out there that can confirm or (better yet) correct this? Harvey
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