48 plymouth. rebuilt generator, polorized, and new battery. Anybody know what the problem might be? the needle of the amp meter moves in the positive direction when I use the turn signal- if that means anything. my neighbor, who helps me said he wants to adjust something ???
Put a voltmeter on the battery and note what the voltage is. Then start the engine,bring it up to high idle or 1500 RPM and recheck the voltage at the battery. I believe it should be 7.5 volts. If less it won't charge the battery. If voltage is the same as in the 1st reading there is no output.
If the ammeter needle moves to the positive side when you operate he turn signals it means either the ammeter is hooked up incorrectly (wrong polarity) or, most likely, the battery is installed with the wrong polarity - negative terminal is grounded instead of the positive.
A more remote possibility is that the generator is incorrectly polarised.
Brian
I once had the un-nerving experience of starting up a car with the generator polarized in the opposite direction to the battery polarity. The generator makes an almighty screeching sound and appears to be on fire. This is because the battery is discharging directly to ground through the generator windings and the faster the engine turns the greater the 'assist' the current gets as the generator raises it's voltage more and more. It also tends to weld the cut-out points together forever and ever. The cut-out relay is not 'polarity conscious' and will close on either polarity.
I was able to remove the armature and sand down the commutator and install a new cut-out and after polarizing the generator in the right direction, everything returned to normal.
? So unless you have this set of conditons, I wouldn't suspect reversed polarity.
I do agree that the ammeter is either hooked up backwards or the system,read 'battery', is hooked up 'backwards'. The battery is negative grounded instead of positive ground. This will not hurt the ammeter but could do other damage as above.
The appearance of the small load when the directional signals are used is OK just the matter of the upscale reading is troubling. As 12905 says the battery seems to be 'backwards'. If you haven't rewired the dash, then that's almost certainly the case. With the engine off, therefore the generator is out of circuit, then any upscale reading by use of a lamp has to mean the battery is hooked up wrong.
If this is the case, as I've cautioned above, make sure you re-polarize the generator before starting up.
But I would start by correcting the ammeter readings before tackling the generator with a running engine.
The car will actually start and run WITHOUT the generator hooked up. If you use this as a step in your trouble shooting, then you will see the ammeter with a slight discharge with just the ignition coil load and then progressively more and more needle deflection to 'DISCHARGE' as lamps are turned on.? ?
? If all this works up to now then polarize the generator and and start up. If now the 'discharge' readings aren't corrected to 'charge' readings by the generator, then you're into voltage regulator/generator problems. Be aware that the old generator systems automatically disconnect the generator from the car when the engine is idling. This is because the battery has a greater terminal voltage then the generator and it will discharge backwards through the generator. Sort of a slow motion version of reversed polarization. So you have to speed up the engine to get any charge indication. (That's why the more I goosed the engine, the more flames came out of the generator and the louder the screech became.)
Good luck.? ? ?
? ?
I have owned, worked on, and enjoyed mostly early American cars, from 1924 -1954 (mostly 6V mopars ) since i was 16 , i am now coming up 69 , and until i joined this forum i had never heard of polarising the generator ,( i actualy asked my auto elictician about polarising the gen , his answer ,was what!) all i have ever done when i had one that gave up , is replace it with another , usualy a used one , and have never had any problems .
Like Elmo 54, I'm also on the high side of 60 (I'll be 65 soon), and I've been "fixing" cars since I was 16, some with more success than others.
Here's what the 16th edition of MOTOR'S Repair Manual (covers 1935-48 American autos) has to say about polarizing generators:
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 plarizes 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 cols wil polarize the generator correctly.
I remember buying replacement voltage regulators in the 1960s, and they included polarizing instructions in the box that the regulator came in.
I have a spare voltage regulator (Echlin VR27- it is for 1950-55 Plymouths with the GGW generator). The included instructions state that to polarize the generator, connect a jumper wire to the armature terminal of the regulator and flash the other end momentarily to the battery terminal of the regulator.
Regards,
Pat O'Connor
One more hint to test if the battery is in backwards. Turn the key to the on position (don't start the car) and watch the ammeter needle. If it goes to the plus side, the battery is in wrong.