1950s Generator polarity

[Lexi]

Have a question. Using one of those quick green disconnects on my battery's positive side, I shut off my car's power this weekend as I was working for several hours inside my dash of my '56 Caddy. It is basically a stock vehicle, still equipped with it's 12 volt generator. My question is, after having the battery disconnected for several hours should I re-polarize the system at the voltage regulator or is it probably not required? When I started up my car to move it to storage, I remembered that some recommend re-polarizing after a long disconnect. I assume that if there is a problem my generator would not be charging normally after restart? I had a quick plug in voltage meter in my glove box which I plugged into the cigarette lighter and voltage seemed normal (i.e. not marked as a negative reading, rather still plus +13 - +14 volts). I also seem to recall that disconnects are best placed on the negative side of the battery but those 3EE long narrow batteries with a short negative ground (under the fender of all places), precludes me from attaching the cut off there. So negative cable was always attached during shut off. Any comments? Thank you. Clay/Lexi

[64\/54Cadillacking]

Hey Clay, I don't think you have to re-polarize the system after only a few hours of the battery being disconnected. If the battery is charging fine after it being disconnected, then you shouldn't have anything to worry about.

I always disconnect the negative battery cable when Pinky sits.

My negative bat cable was pretty nasty looking when I first got the Caddy, but I replaced it with a longer one, including the positive cable because of how short the old ones were. Got them at Napa which are good quality cables.

[Lexi]

Thankyou Cadillac King. So far it seems OK. Clay/Lexi

[CadillacFanBob]

Clay, No worries I second Cadillacking, especially because you put your trusty digital plug in volt meter in cigarette lighter socket (I purchased 2 of these digital volt meters on your suggestion)

Bob

[TJ Hopland]

The generator doesn't use any actual magnets, they are all electro magnets.  The way a generator gets started is some if the internal parts get magnetized from being around the electro magnets when its operating.  The metal parts generally holds enough magnetism for long enough that when its spun up again there is just enough magnetism left to start to generate some power.  That power then powers the electro magnets which get stronger so more power more magnetism so more power to the point where the regulator kicks in to cut the power/strength of the magnets thus the voltage.

The polarity polarizing part of things has to do with the direction of this residual magnetism that stays in the generator.  The direction/polarity that these metal parts got magnetized is what determines what polarity electrically wise it will start to generate once its spun up again. 

For doing pos/neg ground conversions you can carefully force this by sending power the other direction into the gen so it will magnetism the internals the other way.  OR same thing if it just sat for a really long time, usually several years and the internals just lost that magnetism.       

[CadillacFanBob]

@TJ Hopland thank you for the detailed information for me and forum members

Bob