charging system joins the party late

Shake-N-Bake

Well Known Member
I am looking for help to solve a problem I am having with our '61 Bel Air. At idle, or even elevated idle....the charging system doesn't 'wake up' (best description for behavior that I am observing...). I have an amp gauge and volt meter connected the battery sits right around 12.4-12.7 volts at idle. I rev the engine to around 1500 RPM and the readings stay the same. Amp gauge shows the battery is slightly discharging. If I turn on the headlights, then the discharge rate increases to about 15 amps. After a while, the GEN light will start to glow I presume because the voltage has dropped to around 12.0-12.2 range. When I measure volts at the armature terminal, I get about 13.8-14.0 volts. When I measure at the field terminal, I get about 9-10 volts

If I rev the engine one time very briefly to around 3500 RPM, then the GEN light extinguishes, the amp gauge jumps to about 20 amps charge. If I cruise around for a short while then the amp gauge charge reduces to slightly above zero, even with the lights on. If I activate the turn signals at idle while sitting at a stop light, then the amp gauge reads a discharge of around 2-6 amps, bouncing back and forth as the signal flashes. I figure this is normal because once I get up to cruising speed the amp gauge will show about 4-5 amps charge for a few seconds and then go back to near zero.

Every once in a while, if I am idling in a parking lot or for an extended period of time with the lights on the amp gauge might begin showing a 15 amp discharge and the GEN light will glow again. A short blip of the throttle resolves the issue as before and I drive around normally for a while again. However, when the GEN light is off....and the amp gauge shows it's charging....I only see about 12.8-13.0 volts. I would expect the volts at charge to be high 13s or low 14s.

Do I need to adjust my regulator? The generator was recently rebuilt by a local reputable generator shop. The voltage regulator is new. I did polarize the generator per the instructions (by briefly touching the BAT and ARM terminals on the voltage regulator with a jumper wire...) If I do need to adjust my regulator, how do I go about doing that? I've read the shop manual and I got myself confused.

Thanks.
 

62impala409

 
Supporting Member 1
Others, will chime in, but I believe you will have to polarize the generator, what they call a "flash the field" process to bring the generator back on line. This is required whenever a generator is removed from service and reinstalled. You can check the shop manual for the exact process. I have done it many times years ago whenever I repaired a generator. This is some info.



Motors Manual said:

After a generator has been repaired and reinstalled on a vehicle or at any time after a generator has been tested, it must be repolarized to make sure that it has the correct polarity with respect to the battery it is to charge. Failure to do this may result in burned circuit breaker contacts, a run-down battery and possibly serious damage to the generator itself. The procedure to follow depends upon whether the generator field is grounded internally or is grounded externally through the regulator.

If the generator is externally grounded, momentarily touch a jumper lead to the armature and battery terminals of the regulator. This must be done after all leads have been connected but before starting the engine. This allows a momentary surge of current to flow through the generator which correctly polarizes it.

If the generator is internally grounded, disconnect the lead from the field terminal of the regulator and momentarily touch this lead to the regulator battery terminal. The surge of current which flows through the field coils will polarize the generator correctly.
 
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Shake-N-Bake

Well Known Member
Others, will chime in, but I believe you will have to polarize the generator, what they call a "flash the field" process to bring the generator back on line. This is required whenever a generator is removed from service and reinstalled. You can check the shop manual for the exact process. I have done it many times years ago whenever I repaired a generator. This is some info.


...

Thanks for the reply. I did polarize the generator using the method you describe. Same method was listed with the instructions in the relay as well as the shop manual so I figure it's working well. If I try the 'briefly ground the field' test per the shop manual, then generator output increases to maximum so I am pretty sure the generator is functioning normally. I've never had to troubleshoot a generator/regulator system before but everything I am seeing right now is telling me the voltage regulator coil has it's spring tension too high and the field voltage isn't strong enough to overcome it. Before I begin adjusting the contact, I wanted to check with the group here to make sure I didn't overlook anything first.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Just be careful when adjusting the regulator,it's easy to over do it and damage the generator.The main reason that the car makers switched to the alternators was that generators don't charge at idle speeds,while alternators do.I think that you're correct about the regulator needing some tweaking based on your first post,it is cutting in too high,it should come in closer to 2,000 rpm.
 

Shake-N-Bake

Well Known Member
Following up with the resolution to this issue...
I took the cover off the new voltage regulator and it wasn't adjustable....at least not like the OEM units are (via adjusting screw in the coil base). So, I just removed it from the car and returned it to Auto Zone. I then ordered a new voltage regulator from a company online called cpgenerator.com and it works correctly now.

:)
 
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