Alternator whine, ground loop?
09-03-2011, 12:36 PM
#1
Staging Lane
Thread Starter
Alternator whine, ground loop? I installed a PowerBastards 220 amp alternator 2 weeks ago due to my stocker going out. During the install I also changed out my wires to 2 gauge. Ever since switching alternators the new one has had a constant whine, I did a little reading and one site I came upon said alternator whine is due to something called ground loop, I'm not exactly an electrician and I didn't exactly understand what all it said. Here's the link http://www.termpro.com/articles/noise.html Anyone care to explain this to me. The article pertains more to audio compettion but I do have a sub so maybe that something to do with it.
09-03-2011, 12:46 PM
#2
Staging Lane
Thread Starter
Well I read it over and I'm 99% the whine the article is talking about it a whine through the SPEAKERS, not the actual alternator which is not my problem. My alternator itself is what is whining, could it be the alternator isn't perfectly lined up with the rest of the accessories?
09-03-2011, 12:53 PM
#3
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Thrust load (misalignment), cooling fan fins too close to something on
the casing, brushes not bedded in or hitting something that might
eventually scrub its own notch in them, or just noisy / crappy bearings
I would guess,
Ground loop is less likely the problem than simply the fact that the
alt can only push lumpy rectified 3-phase current against the load
and will bump harder against the battery, while heavy load will also
sag the battery more in the valleys. Heavy load current returned
through chassis sheet metal is of course a less than good idea,
less a "ground loop" problem than a simple I*R voltage rise and
any lumpiness in I becomes a point-of-load supply voltage
modulation.
the casing, brushes not bedded in or hitting something that might
eventually scrub its own notch in them, or just noisy / crappy bearings
I would guess,
Ground loop is less likely the problem than simply the fact that the
alt can only push lumpy rectified 3-phase current against the load
and will bump harder against the battery, while heavy load will also
sag the battery more in the valleys. Heavy load current returned
through chassis sheet metal is of course a less than good idea,
less a "ground loop" problem than a simple I*R voltage rise and
any lumpiness in I becomes a point-of-load supply voltage
modulation.
09-03-2011, 06:52 PM
#4
Staging Lane
Thread Starter
Could be very possible the alternator isn't alligned perfectly because one of the bolts was very difficult to torq down all the way, of course its raining right now so I can't crawl up under it but I'll definitely give that a shot.
09-04-2011, 04:01 PM
#5
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Another thought is that because the alt will push harder (more current
pulsation) there could be magnetostriction type squealing in the iron.
The way to check that would be to see if it modulates with load after
plain mechanical noises have been ruled out.
Nothing much you could do about it, but it is a possibility. Same as
the squeal you hear out of old TVs and monitors' flyback transformers.
pulsation) there could be magnetostriction type squealing in the iron.
The way to check that would be to see if it modulates with load after
plain mechanical noises have been ruled out.
Nothing much you could do about it, but it is a possibility. Same as
the squeal you hear out of old TVs and monitors' flyback transformers.
09-05-2011, 12:09 AM
#6
Staging Lane
Thread Starter
Yeah it does have a real mellow hum like what you're talking about, I still haven't had a chance to retorque the bolts due to this dang tropical depression in the Gulf but I plan on doing so tomorrow. Thanks for your input though, big help.
