[OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

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[OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

RussellMc
*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
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RE:][OT]:: Likelihood of car alternator fault being due to worn fieldwinding brushes?

Allen Mulvey
Decades ago I had a similar problem with a Subaru. The regulator shorted out and “killed” the alternator. Replacing the regulator resulted in a situation similar to yours. I removed the alternator and discovered that the diodes were attached between two plates. I removed them and used long nosed pliers to crush the existing diodes. Holes were then drilled near their weld points and I soldered in some general purpose diodes from Radio Shack. It worked well until we got a new car a couple of years later.

Allen

From: RussellMc
Sent: Tuesday, September 8, 2020 10:06 AM
To: Microcontroller discussion list - Public.
Subject: [CAUTION: Failed DKIM Test][OT]:: Likelihood of car alternator fault being due to worn fieldwinding 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
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Re: [OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

Bob Blick-5
In reply to this post by RussellMc
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: [hidden email] <[hidden email]> 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
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Re: [OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

John Lawton
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: [hidden email] <[hidden email]> 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
> --
>
>

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Re: [OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

Alan Pearce
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 <[hidden email]> 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: [hidden email] <[hidden email]> 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

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Re: [OT]:: Likelihood of car alternator fault being due to worn field winding brushes?

Richard Prosser
In my (limited) experience, diode failures are far more common than worn
out brushes on the sliprings. It's not like a commutator, there is a smooth
surface for them to run on without switching so wear is minimal. Probably
there is a fuse or fusible link somewhere to protect things if (when) a
diode goes short circuit.
RP

On Wed, 9 Sep 2020 at 07:58, Alan Pearce <[hidden email]>
wrote:

> 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 <[hidden email]> 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: [hidden email] <[hidden email]> 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
>
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