[DeTomaso] Alternator blues....
Guido deTomaso
guido_detomaso at prodigy.net
Thu Oct 6 12:01:07 EDT 2016
I'm lost ... the rectifier diodes, typically six, each transit roughly 1/3 of the alternators output. Collectively they transmit all the output power. Any loads added anywhere tax the diodes.
OTOH, certain cars I'm aware of run many loads through the lamp circuit, bulb test in the example I'm familiar with, and some/many/most alternator voltage regulators can't handle the current. These require a special voltage regulator.
Unlikely the root cause of the problem at hand ... my money is on bad regulator unfortunately inside the GM alternator not conveniently remote mounted.
Or so it seems to me, I could be wrong.
GD
From: Tomas Gunnarsson <guson at home.se>
To: tipo874 at gmail.com
Cc: MikeLDrew at aol.com; detomaso at server.detomasolist.com
Sent: Wednesday, October 5, 2016 11:55 PM
Subject: Re: [DeTomaso] Alternator blues....
If the marginal connection is between battery and ammeter it will
fluctuate between zero and charge. If it's between alternator and
ammeter it will fluctuate between charge and discharge. Right Thomas?
Another thought: Have you by accident hooked anything up to the lamp
post on the alternator (or the wire going between post and dashboard
lamp) that's using significant power? That pin will provide power when
running but the rectifier diodes inside will not be up for the task and
burn out in short time. Just a thought as you've been going through
alternators at high pace. I'd like to disconnect the lamp wire from the
alternator with the engine running and see what happens. Note that the
sense wire will have to stay connected if you have one.
Tomas
<-----Ursprungligt Meddelande----->
From: Thomas Toernblom [tipo874 at gmail.com]
Sent: 3/10/2016 9:49:41 PM
To: MikeLDrew at aol.com
Cc: detomaso at server.detomasolist.com
Subject: Re: [DeTomaso] Alternator blues....
Check the fat wire from B+ (or what it is called on the alt) to the
ammeter. If there is a marginal connection there the voltage can
fluctuate wildly and possibly kill semiconductors in the alt.
> 3 okt. 2016 kl. 18:00 skrev Mike Drew via DeTomaso
<detomaso at server.detomasolist.com>:
>
> All,
>
> Further to my original inquiry, I failed to mention that this is a GM
alternator with built-in regulator, running in the stock three-wire
configuration. Normally it works normally--shows a somewhat strong
charge for a short time after engine start, coming back down to slight
charge when battery is 'full' again, with slight discharge at idle when
fans, lights etc are on.
>
> When it starts acting up, initially the needle bounces erratically
over a small range between slight charge and slight discharge. After a
few minutes of that, it goes into greater discharge mode as it quits
completely.
>
> Mike
>
> Sent from my iPhone
>
>> On Oct 3, 2016, at 8:15, "Himes, Terry (397C)"
<terry.himes at jpl.nasa.gov> wrote:
>>
>> Ditto. I put in 2 rebuilt units and they both failed. Finally bought
>> a new one.
>> No problem since.
>>
>> "A Purple Heart proves you were smart enough to hatch a plan,
>>
>> stupid enough to try it and lucky enough to survive!"
>>
>> Terry W. Himes
>>
>> JPL Jet Propulsion Laboratory
>>
>> Dawn Spacecraft Team
>>
>> Rosetta Sequence Team Lead
>>
>> Phone: (818) 393-6261
>>
>> Cell: (818) 653-8213
>>
>> Fax: (818) 393-3147
>>
>> [1]thimes at jpl.nasa.gov
>>
>> From: DeTomaso <[2]detomaso-bounces at server.detomasolist.com> on
behalf
>> of Julian Kift <[3]julian_kift at hotmail.com>
>> Date: Monday, October 3, 2016 6:57 AM
>> To: "[4]MikeLDrew at aol.com" <[5]MikeLDrew at aol.com>,
>> "[6]detomaso at server.detomasolist.com"
>> <[7]detomaso at server.detomasolist.com>
>> Subject: Re: [DeTomaso] Alternator blues....
>>
>> Mike,
>> I hate chasing these type of electrical problems, but here's some
>> thoughts;
>> i) Battery going bad (how old is it?), requiring the alternator to
have
>> to constantly charge
>> ii) Some alternator re builders are notorious for units failing,
over a
>> 50% failure rate is not uncommon. I had a similar issue with my
GT40;
>> on the third alternator we switched to a higher amp 'new' unit and
>> never had a problem since.
>> iii) It could also be an intermittent short or bad ground
>> Julian
>> ________________________________
>> From: DeTomaso <[8]detomaso-bounces at server.detomasolist.com> on
behalf
>> of Mike Drew via DeTomaso <[9]detomaso at server.detomasolist.com>
>> Sent: Sunday, October 2, 2016 9:11 PM
>> To: [10]detomaso at server.detomasolist.com
>> Subject: [DeTomaso] Alternator blues....
>> Hi guys,
>> Just got home from a terrific weekend in the Sierra foothills; 24
>> Panteras
>> (of the 36 scheduled) took part in the Niello concours at Serrano.
It
>> heaved down with rain for a very brief period, but that rain then
>> turned to snow
>> which kept the large Reno/Tahoe contingent from braving the summit.
>> Still, a great time was had by all who attended, and we drove home
in
>> splendid
>> sunshine.
>> We were driving in Lori's Pantera, which has a flat firewall kit and
>> uses a
>> GM alternator with built-in regulator. She drove the car to Vegas
>> this
>> spring, and the alternator failed while we were there. At first it
>> started
>> acting erratic, with the amp needle bouncing around, and then
finally
>> it quit
>> and just showed a partial discharge. Testing at the battery revealed
>> it
>> was doing nothing at that point. We replaced it with another one,
>> which did
>> exactly the same thing and failed about 50 miles from home.
>> We replaced THAT one, and the third one has worked fine until today.
>> But
>> it probably only has about 250 miles on it or so. On the way home,
>> once
>> again, I noticed the ammeter needle behaving erratically, then it
quit
>> and
>> showed partial discharge for many miles, then briefly came back to
life
>> and
>> showed a very strong charge (since we had been running on battery
power
>> for
>> awhile), then discharged again.
>> Methinks the problem is not simply that alternators are failing, but
>> rather
>> that there is some sort of fault in the electrical system. As
>> electrons
>> are far from my strong suit, I hesitate to start diving it to it
>> blindly.
>> What say all of you?
>> FWIW we've got a spare alternator we will be installing tomorrow,
which
>> almost assuredly will work just fine...for awhile anyway????
>> Mike
>>
>> References
>>
>> 1. mailto:thimes at jpl.nasa.gov
>> 2. mailto:detomaso-bounces at server.detomasolist.com
>> 3. mailto:julian_kift at hotmail.com
>> 4. mailto:MikeLDrew at aol.com
>> 5. mailto:MikeLDrew at aol.com
>> 6. mailto:detomaso at server.detomasolist.com
>> 7. mailto:detomaso at server.detomasolist.com
>> 8. mailto:detomaso-bounces at server.detomasolist.com
>> 9. mailto:detomaso at server.detomasolist.com
>> 10. mailto:detomaso at server.detomasolist.com
>> _______________________________________________
>>
>>
>> Detomaso Email List is not managed by POCA
>> Posted emails must not exceed 1.5 Megabytes
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>> http://server.detomasolist.com/mailman/listinfo/detomaso
>>
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etc.) use the links above.
>>
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or approve the archiving of list messages.
> _______________________________________________
>
>
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-------------- next part --------------
I'm lost ... the rectifier diodes, typically six, each transit roughly
1/3 of the alternators output. Collectively they transmit all the
output power. Any loads added anywhere tax the diodes.
OTOH, certain cars I'm aware of run many loads through the lamp
circuit, bulb test in the example I'm familiar with, and some/many/most
alternator voltage regulators can't handle the current. These require
a special voltage regulator.
Unlikely the root cause of the problem at hand ... my money is on bad
regulator unfortunately inside the GM alternator not conveniently
remote mounted.
Or so it seems to me, I could be wrong.
GD
__________________________________________________________________
From: Tomas Gunnarsson <guson at home.se>
To: tipo874 at gmail.com
Cc: MikeLDrew at aol.com; detomaso at server.detomasolist.com
Sent: Wednesday, October 5, 2016 11:55 PM
Subject: Re: [DeTomaso] Alternator blues....
If the marginal connection is between battery and ammeter it will
fluctuate between zero and charge. If it's between alternator and
ammeter it will fluctuate between charge and discharge. Right Thomas?
Another thought: Have you by accident hooked anything up to the lamp
post on the alternator (or the wire going between post and dashboard
lamp) that's using significant power? That pin will provide power
when
running but the rectifier diodes inside will not be up for the task
and
burn out in short time. Just a thought as you've been going through
alternators at high pace. I'd like to disconnect the lamp wire from
the
alternator with the engine running and see what happens. Note that
the
sense wire will have to stay connected if you have one.
Tomas
<-----Ursprungligt Meddelande----->
From: Thomas Toernblom [[1]tipo874 at gmail.com]
Sent: 3/10/2016 9:49:41 PM
To: [2]MikeLDrew at aol.com
Cc: [3]detomaso at server.detomasolist.com
Subject: Re: [DeTomaso] Alternator blues....
Check the fat wire from B+ (or what it is called on the alt) to the
ammeter. If there is a marginal connection there the voltage can
fluctuate wildly and possibly kill semiconductors in the alt.
> 3 okt. 2016 kl. 18:00 skrev Mike Drew via DeTomaso
<[4]detomaso at server.detomasolist.com>:
>
> All,
>
> Further to my original inquiry, I failed to mention that this is a
GM
alternator with built-in regulator, running in the stock three-wire
configuration. Normally it works normally--shows a somewhat strong
charge for a short time after engine start, coming back down to
slight
charge when battery is 'full' again, with slight discharge at idle
when
fans, lights etc are on.
>
> When it starts acting up, initially the needle bounces erratically
over a small range between slight charge and slight discharge. After
a
few minutes of that, it goes into greater discharge mode as it quits
completely.
>
> Mike
>
> Sent from my iPhone
>
>> On Oct 3, 2016, at 8:15, "Himes, Terry (397C)"
<[5]terry.himes at jpl.nasa.gov> wrote:
>>
>> Ditto. I put in 2 rebuilt units and they both failed. Finally
bought
>> a new one.
>> No problem since.
>>
>> "A Purple Heart proves you were smart enough to hatch a plan,
>>
>> stupid enough to try it and lucky enough to survive!"
>>
>> Terry W. Himes
>>
>> JPL Jet Propulsion Laboratory
>>
>> Dawn Spacecraft Team
>>
>> Rosetta Sequence Team Lead
>>
>> Phone: (818) 393-6261
>>
>> Cell: (818) 653-8213
>>
>> Fax: (818) 393-3147
>>
>> [1][6]thimes at jpl.nasa.gov
>>
>> From: DeTomaso <[2][7]detomaso-bounces at server.detomasolist.com> on
behalf
>> of Julian Kift <[3][8]julian_kift at hotmail.com>
>> Date: Monday, October 3, 2016 6:57 AM
>> To: "[4][9]MikeLDrew at aol.com" <[5][10]MikeLDrew at aol.com>,
>> "[6][11]detomaso at server.detomasolist.com"
>> <[7][12]detomaso at server.detomasolist.com>
>> Subject: Re: [DeTomaso] Alternator blues....
>>
>> Mike,
>> I hate chasing these type of electrical problems, but here's some
>> thoughts;
>> i) Battery going bad (how old is it?), requiring the alternator to
have
>> to constantly charge
>> ii) Some alternator re builders are notorious for units failing,
over a
>> 50% failure rate is not uncommon. I had a similar issue with my
GT40;
>> on the third alternator we switched to a higher amp 'new' unit and
>> never had a problem since.
>> iii) It could also be an intermittent short or bad ground
>> Julian
>> ________________________________
>> From: DeTomaso <[8][13]detomaso-bounces at server.detomasolist.com>
on
behalf
>> of Mike Drew via DeTomaso
<[9][14]detomaso at server.detomasolist.com>
>> Sent: Sunday, October 2, 2016 9:11 PM
>> To: [10][15]detomaso at server.detomasolist.com
>> Subject: [DeTomaso] Alternator blues....
>> Hi guys,
>> Just got home from a terrific weekend in the Sierra foothills; 24
>> Panteras
>> (of the 36 scheduled) took part in the Niello concours at Serrano.
It
>> heaved down with rain for a very brief period, but that rain then
>> turned to snow
>> which kept the large Reno/Tahoe contingent from braving the
summit.
>> Still, a great time was had by all who attended, and we drove home
in
>> splendid
>> sunshine.
>> We were driving in Lori's Pantera, which has a flat firewall kit
and
>> uses a
>> GM alternator with built-in regulator. She drove the car to Vegas
>> this
>> spring, and the alternator failed while we were there. At first it
>> started
>> acting erratic, with the amp needle bouncing around, and then
finally
>> it quit
>> and just showed a partial discharge. Testing at the battery
revealed
>> it
>> was doing nothing at that point. We replaced it with another one,
>> which did
>> exactly the same thing and failed about 50 miles from home.
>> We replaced THAT one, and the third one has worked fine until
today.
>> But
>> it probably only has about 250 miles on it or so. On the way home,
>> once
>> again, I noticed the ammeter needle behaving erratically, then it
quit
>> and
>> showed partial discharge for many miles, then briefly came back to
life
>> and
>> showed a very strong charge (since we had been running on battery
power
>> for
>> awhile), then discharged again.
>> Methinks the problem is not simply that alternators are failing,
but
>> rather
>> that there is some sort of fault in the electrical system. As
>> electrons
>> are far from my strong suit, I hesitate to start diving it to it
>> blindly.
>> What say all of you?
>> FWIW we've got a spare alternator we will be installing tomorrow,
which
>> almost assuredly will work just fine...for awhile anyway????
>> Mike
>>
>> References
>>
>> 1. mailto:[16]thimes at jpl.nasa.gov
>> 2. mailto:[17]detomaso-bounces at server.detomasolist.com
>> 3. mailto:[18]julian_kift at hotmail.com
>> 4. mailto:[19]MikeLDrew at aol.com
>> 5. mailto:[20]MikeLDrew at aol.com
>> 6. mailto:[21]detomaso at server.detomasolist.com
>> 7. mailto:[22]detomaso at server.detomasolist.com
>> 8. mailto:[23]detomaso-bounces at server.detomasolist.com
>> 9. mailto:[24]detomaso at server.detomasolist.com
>> 10. mailto:[25]detomaso at server.detomasolist.com
>> _______________________________________________
>>
>>
>> Detomaso Email List is not managed by POCA
>> Posted emails must not exceed 1.5 Megabytes
>> DeTomaso mailing list
>> [26]DeTomaso at server.detomasolist.com
>> [27]http://server.detomasolist.com/mailman/listinfo/detomaso
>>
>> To manage your subscription (change email address, unsubscribe,
etc.) use the links above.
>>
>> Members who post to this list grant license to the list to forward
any message posted here to all past, current, or future members of
the
list. They also grant the list owner permission to maintain an
archive
or approve the archiving of list messages.
> _______________________________________________
>
>
> Detomaso Email List is not managed by POCA
> Posted emails must not exceed 1.5 Megabytes
> DeTomaso mailing list
> [28]DeTomaso at server.detomasolist.com
> [29]http://server.detomasolist.com/mailman/listinfo/detomaso
>
> To manage your subscription (change email address, unsubscribe,
etc.)
use the links above.
>
> Members who post to this list grant license to the list to forward
any message posted here to all past, current, or future members of
the
list. They also grant the list owner permission to maintain an
archive
or approve the archiving of list messages.
_______________________________________________
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_______________________________________________
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References
1. mailto:tipo874 at gmail.com
2. mailto:MikeLDrew at aol.com
3. mailto:detomaso at server.detomasolist.com
4. mailto:detomaso at server.detomasolist.com
5. mailto:terry.himes at jpl.nasa.gov
6. mailto:thimes at jpl.nasa.gov
7. mailto:detomaso-bounces at server.detomasolist.com
8. mailto:julian_kift at hotmail.com
9. mailto:MikeLDrew at aol.com
10. mailto:MikeLDrew at aol.com
11. mailto:detomaso at server.detomasolist.com
12. mailto:detomaso at server.detomasolist.com
13. mailto:detomaso-bounces at server.detomasolist.com
14. mailto:detomaso at server.detomasolist.com
15. mailto:detomaso at server.detomasolist.com
16. mailto:thimes at jpl.nasa.gov
17. mailto:detomaso-bounces at server.detomasolist.com
18. mailto:julian_kift at hotmail.com
19. mailto:MikeLDrew at aol.com
20. mailto:MikeLDrew at aol.com
21. mailto:detomaso at server.detomasolist.com
22. mailto:detomaso at server.detomasolist.com
23. mailto:detomaso-bounces at server.detomasolist.com
24. mailto:detomaso at server.detomasolist.com
25. mailto:detomaso at server.detomasolist.com
26. mailto:DeTomaso at server.detomasolist.com
27. http://server.detomasolist.com/mailman/listinfo/detomaso
28. mailto:DeTomaso at server.detomasolist.com
29. http://server.detomasolist.com/mailman/listinfo/detomaso
30. mailto:DeTomaso at server.detomasolist.com
31. http://server.detomasolist.com/mailman/listinfo/detomaso
32. mailto:DeTomaso at server.detomasolist.com
33. http://server.detomasolist.com/mailman/listinfo/detomaso
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