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Re: help me understand my voltage... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Fri, 9 Dec 2005 05:56:03
In Reply to: help me understand my voltage..., rsfeller, Thu, 8 Dec 2005 17:04:10 Members do not see ads below this line. - Help Keep This Site Online - Signup |
If the ALT light is on, and you just blip the throttle, I'll bet you see the voltage jump up and the light go off.
This is usually the sign of a weak voltage regulator or alternator. The alternator uses an electromagnet (field coils) to create a magnetic field. When you start the car, current flows through the ALT bulb into the field coils, creating the magnetic field. It isn't a super strong magnetic field, but good enough. That current flow also turns on the bulb. Once the alternator gets spinning, it creates its own current flow, and takes over powering the field coils. Current no longer flows through the bulb, and it goes out.
At slow speed, the alternator doesn't put out a lot of voltage. With the weaker field provided by the current through the bulb, it's even less. In your case, the voltage isn't quite enough for the voltage regulator to take over driving the field coils. When you blip the throttle, the alternator speeds up, the voltage increases, and then the VR can take over.
I know it's only a couple of years old, but that doesn't mean that the VR or alternator can't be bad. And it really isn't bad - it just has trouble getting up on a cold morning. Me too. Frankly, as long as the voltage comes up to a good level once you blip the throttle, there is absolutely NOTHING wrong with just blipping the throttle to get the light to go out. Really. If it does worry you, or if the voltage shows any signs of trouble in normal driving, replace the VR.
posted by 192.249.4...
, Fri, 9 Dec 2005 05:56:03 <-- Viewing This Message
, Thu, 8 Dec 2005 19:13:14
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