> Hi Russell,
> If the brushes have gone bad, it's quite likely that other damage has or will soon happen to the alternator. Since it's a closed loop system, the regulator is going to try to maintain current, so there might be arcing and excess heat which can damage the slip rings and potentially the regulator itself. Not saying that's what's happening here, but just fyi. The damage to the slip rings isn't going to be as bad as what happens in a motor with a slotted commutator, you can probably clean it up good enough to get a few more years before the new brush is gobbled up.
> Cheers, Bob
>
> ________________________________________
> From: piclist-bouncesKILLspammit.edu <.....piclist-bouncesKILLspam.....mit.edu> on behalf of RussellMc
> Sent: Tuesday, September 8, 2020 7:03 AM
> To: Microcontroller discussion list - Public.
> Subject: [OT]:: Likelihood of car alternator fault being due to worn field      winding brushes?
>
> *TL;DR: If a 2001 Toyota Corolla alternator is faulty, how likely it is
> that the field winding brushes have gone open circuit?*
> It's reasonably likely that the alternator is the original one.
> ___________________
>
> My son's 2001 Toyota Corolla has stopped charging its battery.
> The battery holds charge and the alternator does not draw substantial
> current when off.
>
> Indications are that the alternator system is dead.
> It seems likely that there has not been a diode short circuit as in my
> experience these draw substantial battery current.
>
> A mechanic will remove and replace the alternator at an acceptable price.
> Alternator replacement is acceptable if necessary.
>
> *Can anyone suggest how likely it is that the field winding brushes have
> gone open circuit?*
> For various reasons I'm not inclined to do alternator diode replacements or
> other repairs but if brush failure was the cause then a repair sounds
> liable to be a sensible solution.
>
>
>
>          Russell McMahon
> --
>
>

>
> Sounds like a clear case for fitting a reconditioned unit.
>
> John
>
> On 08/09/2020 16:48, Bob Blick wrote:
> > Hi Russell,
> > If the brushes have gone bad, it's quite likely that other damage has or will soon happen to the alternator. Since it's a closed loop system, the regulator is going to try to maintain current, so there might be arcing and excess heat which can damage the slip rings and potentially the regulator itself. Not saying that's what's happening here, but just fyi. The damage to the slip rings isn't going to be as bad as what happens in a motor with a slotted commutator, you can probably clean it up good enough to get a few more years before the new brush is gobbled up.
> > Cheers, Bob
> >
> > ________________________________________
> > From: piclist-bouncesspam_OUTmit.edu <@spam@piclist-bouncesKILLspammit.edu> on behalf of RussellMc
> > Sent: Tuesday, September 8, 2020 7:03 AM
> > To: Microcontroller discussion list - Public.
> > Subject: [OT]:: Likelihood of car alternator fault being due to worn field      winding brushes?
> >
> > *TL;DR: If a 2001 Toyota Corolla alternator is faulty, how likely it is
> > that the field winding brushes have gone open circuit?*
> > It's reasonably likely that the alternator is the original one.
> > ___________________
> >
> > My son's 2001 Toyota Corolla has stopped charging its battery.
> > The battery holds charge and the alternator does not draw substantial
> > current when off.
> >
> > Indications are that the alternator system is dead.
> > It seems likely that there has not been a diode short circuit as in my
> > experience these draw substantial battery current.
> >
> > A mechanic will remove and replace the alternator at an acceptable price.
> > Alternator replacement is acceptable if necessary.
> >
> > *Can anyone suggest how likely it is that the field winding brushes have
> > gone open circuit?*
> > For various reasons I'm not inclined to do alternator diode replacements or
> > other repairs but if brush failure was the cause then a repair sounds
> > liable to be a sensible solution.
> >
> >
> >
> >          Russell McMahon
> > --
> >
> >
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

> I would agree. A reconditioned unit will (should) also have its
> bearings replaced, which will probably be required after almost 20
> years.
>
> On Tue, 8 Sep 2020 at 17:34, John Lawton <RemoveMEpiclistTakeThisOuTjle.co.uk> wrote:
> >
> > Sounds like a clear case for fitting a reconditioned unit.
> >
> > John
> >
> > On 08/09/2020 16:48, Bob Blick wrote:
> > > Hi Russell,
> > > If the brushes have gone bad, it's quite likely that other damage has
> or will soon happen to the alternator. Since it's a closed loop system, the
> regulator is going to try to maintain current, so there might be arcing and
> excess heat which can damage the slip rings and potentially the regulator
> itself. Not saying that's what's happening here, but just fyi. The damage
> to the slip rings isn't going to be as bad as what happens in a motor with
> a slotted commutator, you can probably clean it up good enough to get a few
> more years before the new brush is gobbled up.
> > > Cheers, Bob
> > >
> > > ________________________________________
> > > From: spamBeGonepiclist-bouncesspamBeGonemit.edu <TakeThisOuTpiclist-bouncesEraseMEspam_OUTmit.edu> on behalf of
> RussellMc
> > > Sent: Tuesday, September 8, 2020 7:03 AM
> > > To: Microcontroller discussion list - Public.
> > > Subject: [OT]:: Likelihood of car alternator fault being due to worn
> field      winding brushes?
> > >
> > > *TL;DR: If a 2001 Toyota Corolla alternator is faulty, how likely it is
> > > that the field winding brushes have gone open circuit?*
> > > It's reasonably likely that the alternator is the original one.
> > > ___________________
> > >
> > > My son's 2001 Toyota Corolla has stopped charging its battery.
> > > The battery holds charge and the alternator does not draw substantial
> > > current when off.
> > >
> > > Indications are that the alternator system is dead.
> > > It seems likely that there has not been a diode short circuit as in my
> > > experience these draw substantial battery current.
> > >
> > > A mechanic will remove and replace the alternator at an acceptable
> price.
> > > Alternator replacement is acceptable if necessary.
> > >
> > > *Can anyone suggest how likely it is that the field winding brushes
> have
> > > gone open circuit?*
> > > For various reasons I'm not inclined to do alternator diode
> replacements or
> > > other repairs but if brush failure was the cause then a repair sounds
> > > liable to be a sensible solution.
> > >
> > >
> > >
> > >          Russell McMahon
> > > --
> > >
> > >
> >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>