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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3547 Location: San Diego (Encinitas)
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Posted: Fri Jul 01, 2016 10:10 am Post subject: Re: Charging System |
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Tcash wrote: |
Could you wire in a resister on the current relay to increase the amps say from 30A to 38A?
Or would it require rewinding? |
I suspect that you could. You need to bypass 8 amps around the coil. The value of the resistor should be (30 / 8 ) x value of the resistance of the current relay coil. De-winding might also be an option. Magnetic field strength = current x turns, so You'd have to remove 8 / 38 = 21% of the heavy winding (thus keeping the ampere-turns value constant).
Sometime if I get my hands on a solid state model, I'll work out what it takes to modify for 38 amps. _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Fri Jul 01, 2016 2:19 pm Post subject: Re: Charging System |
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Telford, I am always learning something new from you.
Thank you
I came from the old school way of replacing the Voltage Regulator (VR) with the generator. Most places would not warranty the Gen if you didn't.
This was in the days when you repaired starters and gens if you could, rather than taking them in for a rebuild.
With the supply dwindling and the cost going up on 38A VR's, it has gotten to the point to where it's worth a little time to test and repair them I think.
Thanks again
Tcash |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3547 Location: San Diego (Encinitas)
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Posted: Fri Jul 01, 2016 3:14 pm Post subject: Re: Charging System |
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Tcash wrote: |
I came from the old school way of replacing the Voltage Regulator (VR) with the generator. Most places would not warranty the Gen if you didn't. |
Back when this stuff was readily available, that made sense (from their point of view). Guaranteed to fix the problem...
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This was in the days when you repaired starters and gens if you could, rather than taking them in for a rebuild. |
Especially considering 'rebuilt' meant a fast sandblast, slap in some brushes and spray it silver. Still does, actually. Took apart a 'rebuilt' unit once for a guy and the bearings were full of old grease and sandblast sand. "Lifetime" warranty. Short lifetime.
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With the supply dwindling and the cost going up on 38A VR's, it has gotten to the point to where it's worth a little time to test and repair them I think. |
Definitely. Sometimes, just pulling a strip of 400 grit wet-or-dry through the points is all it needs to straighten out its issues.
No problem. Any time. _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Fri Sep 01, 2017 10:04 am Post subject: Alternator diode testing AC leakage |
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Alternator diode testing AC leakage
telford dorr wrote: |
Regarding test #1 above ^^^:
Some (cheaper) DMMs have AC ranges that don't reject any applied DC voltage. These meters can't be used to test for AC ripple.
To check your meter: set to AC, 20 volt range. With the engine not running, connect the meter across the battery. If it reads 12 volts, then the meter does not reject DC on the AC ranges, and can't be used for the ripple test.
FYI |
Last edited by Tcash on Fri Sep 01, 2017 12:53 pm; edited 1 time in total |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3547 Location: San Diego (Encinitas)
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Posted: Fri Sep 01, 2017 12:30 pm Post subject: Re: Charging System |
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Regarding test #1 above ^^^:
Some (cheaper) DMMs have AC ranges that don't reject any applied DC voltage. These meters can't be used to test for AC ripple.
To check your meter: set to AC, 20 volt range. With the engine not running, connect the meter across the battery. If it reads 12 volts, then the meter does not reject DC on the AC ranges, and can't be used for the ripple test.
FYI _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Fri Sep 01, 2017 12:55 pm Post subject: Re: Charging System |
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Good FYI. I did not know that.
I added it to the post.
Thank you
Tcash |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Thu Jun 07, 2018 9:41 pm Post subject: Commutator Stone |
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Thanks to asiab3
commutator Stone seems to work pretty well on brushes too!
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