[Spridgets] How can you kill an alternator

Trevor Jessie trevor.jessie at gmail.com
Mon Feb 2 10:34:10 MST 2015


I'm just trying to rule out possibilities on how I'm killing so many
alternators.  They fail slowly.  Gradually requiring more and more rpms
before they start charging and eventually they quit charging regardless on
rpms.  I'm on my fourth "rebuilt" Lucas unit from a major chain autoparts
store.

On Mon, Feb 2, 2015 at 12:05 PM, Rick Fisk via Spridgets <
spridgets at autox.team.net> wrote:

> Alternators have to turn about 3000 rpm before they start to really
> produce.  The typical automotive alternator turns three times faster than
> the engine.  If your engine is idling at 700 rpm it's below the point where
> the alternator makes current and your warning light comes on.
>
> If your engine turns 6 grand the alternator is turning 18,000 rpm's!  So
> Trevor, I think the answer to your question is that the bearings will fail
> before the electronics.  The output of an alternator is a straight line
> once it gets up to speed and stays there throughout the rpm range.
>
> Sent from my keyboard
>
> > On Feb 2, 2015, at 11:39 AM, Larry Macy via Spridgets <
> spridgets at autox.team.net> wrote:
> >
> > So how come my waring light comes on when at low RPM’s and I have a GM
> alternator?
> >
> > Larry
> >
> >> On Feb 2, 2015, at 11:17 AM, tncarnut1 via Spridgets <
> spridgets at autox.team.net> wrote:
> >>
> >> If you're thinking that the output of an alternator varies with RPM,
> you are mistaken. That is the functional difference between an alternator
> and a generator. Generator output varies with RPM (why lights can go dimmer
> at idle on some cars), alternator does not. If I misunderstood your
> question, sorry.
> >>
> >> - David
> >>
> >>
> >> Sent via the Samsung GALAXY S® 5, an AT&T 4G LTE smartphone
> >>
> >>
> >> -------- Original message --------
> >> From: Trevor Jessie via Spridgets <spridgets at autox.team.net>
> >> Date:02/02/2015 5:41 AM (GMT-06:00)
> >> To: Spridgets <spridgets at autox.team.net>
> >> Cc:
> >> Subject: [Spridgets] How can you kill an alternator
> >>
> >> My real question is this :  assuming the bearings do not fail, how fast
> can you turn an alternator before it toasts something electronic?   Is
> there a huge margin, or are they engineered near their limited rpm?
> >>
> >> -Trevor
> >>
> >> ------------------------
> >>
> >> spridgets at autox.team.net
> >>
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> >
> > --
> >
> > Larry B. Macy, Ph.D.
> > macy at upenn.edu
> > Senior IT Program Director
> > Neuropsychiatry Section
> > Department of Psychiatry
> > University of Pennsylvania
> > 3400 Spruce St. - 1015 Gates
> > Philadelphia, PA 19104
> >
> > The bottom line: Sure, there's pain in adopting the Mac. But if I accept
> > that, I get to use a computer that works, and that pretty much does what
> I
> > expect and want a computer to do.
> > Stewart Alsop
> > FORTUNE.com
> > Monday, June 25, 2001
> >
> > ------------------------
> >
> > spridgets at autox.team.net
> >
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> ------------------------
>
> spridgets at autox.team.net
>
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