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1956 generator and voltage reg

Started by caddie c, September 07, 2016, 09:15:00 PM

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caddie c

1956 Cadillac 62 series my generator light in on all the time is there a way to determine which has gone bad or going bad.Is there a way to also test voltage from generator and regulator and how to polarize generator thanks

Bobby B

All the info you need pertaining to your specific vehicle is in your service manual. Good investment. Did you at least perform Diagnostic Test 101 with a Voltmeter on the battery while running, higher RPM, and then adding a load to see what the output is?
                                                                             Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

wbdeford

Quote from: Bobby B on September 07, 2016, 09:43:30 PM
All the info you need pertaining to your specific vehicle is in your service manual. Good investment. Did you at least perform Diagnostic Test 101 with a Voltmeter on the battery while running, higher RPM, and then adding a load to see what the output is?
                                                                             Bobby

I don't know about the '56 manual, but the '57 manual is a little difficult to understand without a fair amount of previous electrical knowledge.  It also assumes you have a very particular brand and style of meter.  The '58 supplement seems more general, but it gives very thorough procedures involving multiple meters and 25ohm, 25Watt potentiometer, which most people don't have.  What it doesn't do is give any simple tests that an untrained person can easily understand.

The attached is a bit easier to understand.  I got it from another member when I asked a similar question.

Polarity is easy to set.  Just momentarily attach a jumper wire to the GEN and BAT terminals on the regulator (engine off).
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

dplotkin

#3
There are two ways to best test a generator. The first & easiest is with engine running above idle and a volt-ohm meter across the battery, ground the field terminal on the generator with a jumper, and only long enough to get a reliable average reading. This drives the unit to full output and depending upon engine RPM will show anywhere from 18 to 20 or more volts. If not, the generator is bad. The second is to disconnect all wires from the generator & completely remove the belt. Use jumper cables to connect the battery positive to the A terminal on the generator and the negative to the field terminal on the generator. If the generator then spins like a motor, its good.

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

wbdeford

Quote from: dplotkin on September 08, 2016, 11:58:17 PM
There are two ways to best test a generator. The first & easiest is with engine running above idle and a volt-ohm meter across the battery, ground the field terminal on the generator with a jumper, and only long enough to get a reliable average reading. This drives the unit to full output and depending upon engine RPM will show anywhere from 18 to 20 or more volts. If not, the generator is bad. The second is to disconnect all wires from the generator & completely remove the belt. Use jumper cables to connect the battery positive to the A terminal on the generator and the negative to the field terminal on the generator. If the generator then spins like a motor, its good.

Dan
The '58 shop manual supplement says "Never ground the generator field with the regulator connected to the generator or you will "instantly burn up the upper set of contact points on the voltage regulator".
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville

dplotkin

Isn't that an exception for double contact regulators used with A/C cars? (In which case you are duly noted).

Dan
56 Fleetwood Sixty Special (Starlight silver over Dawn Grey)
60 Buick Electra six window
60 Chrysler 300 F Coupe
61 Plymouth Savoy Ram Inducted 413 Superstock
62 Pontiac Bonneville Vista
63 Chevy Impala convertable
63 Ford Galaxie XL fastback
65 Corvette convertable 396
68 Chrysler New Yorker

wbdeford

Yes--sorry, you're right--just the double contact regulator, which was used on A/C in 1958.  I just noticed that in 57, it was only used on Fleetwood 75 and Commercial Chassis that had A/C, so apparently not on "regular" cars at all.  So, for the OP, this caution may not apply. 
1958 Sedan de Ville

Past:
1956 Fleetwood 75 Sedan
1957 Fleetwood 60 Special
1958 Miller-Meteor Futura Landau Duplex
1960 Coupe de Ville
1966 De Ville Convertible
1970 De Ville Convertible
1971 Eldorado Convertible
1979 Sedan de Ville
1980 Seville