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So I got my alternator back today, and the rectafier(im not sure if its spelled right) was bad? Was causes these to go bad? I can understand the bushings, the bearings and such but how does a rectafier go out, and what is a rectafier?
A rectifier is a device which converts alternating cuurent (AC) into direct current (DC). The alternator produces AC current and it must be converted to DC to charge batteries and run accessories.
Diodes (rectifiers) go bad for usually two reasons only:
1. They get real HOT.
or
2. They pass too much current, which causes them to get hot, which causes them to fail (see #1).
There is actually a third reason, which is getting subjected to a voltage past which they were rated, but that's almost never a reason in automotive applications.
Pop
Last edited by SpringerPop; Aug 28, 2007 at 04:48 PM.
Diodes (rectifiers) go bad for usually two reasons o
Pop
Hey Pop...I got a question for you . I thought a diode was a one way valve...lets current run one way, but not the other. So a rectifier is the same as a diode? I always thought a rectifier took AC to DC and an inverter was DC to AC. If you are too old to be too smart, I am too old to be so dumb!
First, let me clarify why an alternator uses diodes. It's a three-phase AC generator with diodes to rectify that AC into DC. It uses six diodes in its rectifier pack to do this, two for each phase. If any of them go bad (either short or open), youse gotsa' problem! An open diode gives you reduced output capacity, but a shorted one gives you a blown fusible link or smoke! OK so far?
A diode is a component. It's a stand-alone device that passes current in one direction, and blocks it when the current attempts to go the other.
A rectifier is usually defined as a device which turns AC into DC. It's usually some kind of assembly, and may (and usually does) contain more than one diode. But, if the purpose of your rectifier is to turn single-phase AC into half-wave-rectified DC, then one diode is enough to be called a rectifier.
For our purposes here, rectifiers will contain diodes, but not the other-way-around.
Pop
Last edited by SpringerPop; Aug 28, 2007 at 06:09 PM.
First, let me clarify why an alternator uses diodes. It's a three-phase AC generator with diodes to rectify that AC into DC. It uses six diodes in its rectifier pack to do this, two for each phase. If any of them go bad (either short or open), youse gotsa' problem! An open diode gives you reduced output capacity, but a shorted one gives you a blown fusible link or smoke! OK so far?
A diode is a component. It's a stand-alone device that passes current in one direction, and blocks it when the current attempts to go the other.
A rectifier is usually defined as a device which turns AC into DC. It's usually some kind of assembly, and may (and usually does) contain more than one diode. But, if the purpose of your rectifier is to turn single-phase AC into half-wave-rectified DC, then one diode is enough to be called a rectifier.
For our purposes here, rectifiers will contain diodes, but not the other-way-around.
Well mine went out because of a bad (loose) connection causing it to get hot and fail. So now that I have my newly rebuilt one in there I am checking those connections every 6mo from now on to make sure they are tight!