61 Caddy electrics question

I just scored a 61 Caddy limo and after getting it home realized that it has a generator and not an alternator. Now it's been awile since I messed with one of these and my Chiltons manual is boxed up in the ba*****t so, is this a 12volt electric system. I'm ***uming it is and since it has a generator would it be positive ground? Thanks, Ed

 

Probably 12V neg ground. Pos ground mostly died with the 6v cars.

 

Yep Neg Ground pretty sure GM never went the Positive ground route. Limo Pics coming ?

 

Yep, 12 volt negative ground.

 

Ford did positive ground to get around a GM patent. Henry was no fool.

 

OK thanks. It's the same age as me and about in the same shape. Last registered in 1977 and barn stored ever since. I'm really diggin on this car.

 

Let me know if you need any engine parts for your car; brackets, pulleys, starter, generator, etc... I keep a lot of 60 and 61 Cadillac stuff.

 

definitely 12V neg

 

Only 12V pos ground I know of is English cars such as early MG's.

 

Thanks, I'll keep that in mind. I do have a question about my rims. I have different styles on the rear than the front. The rears look like the center is inside out but they aren't. The fronts look like regular rims. Any ideas?

 

'Generator' or 'alternator' has NOTHING to do with whether the car is positive or negative ground.

GM cars are negative ground. A few makes used positive ground, including early MoPars and many British cars, as has already been pointed out.

GENERATOR: a device that produces direct current. DC. Nothing more than an DC electric motor that is spun. Field windings provide magnetism. The amount of field current (controlled by your voltage regulator) determines the output of the unit.

ALTERNATOR: a device that produces alternating current. AC. Nothing more than a three-phase AC electric motor that is spun. Field windings again control the output, and again are controlled by the voltage regulator. BUT MY CAR RUNS ON DC, HOW CAN THE ALTERNATOR BE AC??? Easy. There are diodes inside the altrernator that rectify the AC current. In other words, they transform the AC to DC.

Alternators pack a lot more punch (output current, or amps) into a smaller package with less material (copper) and produce more amps at lower rpms, so that is why the industry went to alternaotrs over generators.

That said, there is nothin wrong with a generator and they are really easy to rebuild yourself.

Now, if you had an alternator designed for negative ground, could you make it positive ground? Yes, turn around the diodes. Electrically this is all you have to do although the reality of how the diode packs are built and the way their heat sinks and so on would make this a bt of a science project. But electrically, that's all there is to it.

Generators set up for one ground or another can be changed. In fact, in the old days, this sometimes happened accidentally when a new battery or voltage regulator was installed. The generator would flip its polarity. The technique to correct was called "flashing" and I will bet a dollar to a donut that only a few of us old farts remember that trick.

 

This old fart knew it as polarizing the generator.

 

The Caddy's of that era had oddball rims which would take the wheel cover-I found out by trying to fit one on a (same bolt pattern but not a Caddy) rim, it wouldn't go on, until i did some measurements and found out the truth. Try fitting your wheel covers , you may have a couple of non-genuine rims on there.

 

Cadillacs are 12v Neg. Ground.Generator to Alternator swaps on these are generally easy.