Polarity, am I wrong.

David G · Feb 8, 2017

I have heard statements on here that the voltage regulator cares about polarity. I believe that the mechanical regulators do not care what the polarity Solid state devices like the diodes in alternators and the solid state regulators do care about the polarity. You polarize the generator, not the regulator to set the residual magnetism in the fields.

I also believe that making a blanket assumption on what voltage or polarity a piece of equipment is configured for is wrong. Too much time has passed since the equipment is built, and a field verification should always be done to confirm what the current configuration is.

Thanks

da.bees · Feb 8, 2017

While it might be true that regulators"don't care",people do care. Having various polarity from machine to machine would result in a lot of reverse installations and booster cable connections in the field.

Steve@Advance · Feb 8, 2017

I could be completely off track here, happened before...

But I'm thinking the difference is the composition of the contact material.

Seems I remember there is a difference in the metals used, something to do with the polarity and the nature of the arc transferring material from one contact to the other.

DC is very aggressive when it comes to arcing, and a regulator is basically arcing constantly to maintain the proper voltage. The result is a shortened life of the contacts if the regulator is labeled positive or negative ground and is reversed. Chances are the aftermarket ones don't have this feature, and don't care.

BobReeves · Feb 8, 2017

Once bought a 60's something Ford station wagon at auction for cheap. Drove it for several months with the radio and dash gauges not working. All the time thinking it was positive ground like it was hooked up when I bought it. Someone told me that it came out of the factory negative ground so I switched the battery. Amazingly the radio started working along with the dash gauges. It had a generator and didn't seem to care, it and the regulator was working with the battery hooked up backwards and worked fine when I switched it.

Would guess you are right in that the regulator doesn't care but would check and configure it the way it came from the factory.

Butch(OH) · Feb 8, 2017

You are correct in that a (mechanical) regulator can be used with either polarity and it will work BUT back when a person could purchase a good regulator (and you cannot now except for old stock) the contact materials differed so as to optimize the life of the unit. The difference between a + ground regulator and a - ground was simply which side of the contacts each specific material was used. If any regulators are built this way now I am not aware of them. When I need a regulator I search Ebay and buy it old stock, often for less than the newly manufactured ones that are for the most part junk when new.

jeffcat · Feb 8, 2017

I agree with you Steve. I can remember going through the NAPAbook many years ago and there were pos. And NEG. Regulators.

M-MAN · Feb 8, 2017

Delco Remy who built most of the voltage regulators we refer to must think you are wrong. They built positive ground regulators(and were marked as such), negative ground regulators(and were marked as such) and later on regulators that didn't care as you suggest. Other manufactures had similar designated regulators. Yes you polarize the genny and not the regulator but if it's a designated regulator you might want to listen to the manufacturer to keep the majic smoke in. JMO

Technology and materials have changed over time. It hasn't been that long ago that simple capacitors were polarity sensitive and marked as such.

Bob · Feb 8, 2017

Check out .pdf pages 10 and 11 of the Delco training manual linked below.

It explains voltage regulator polarity and contact material from the point of view of the Delco engineers, "back in the day".

I wonder how many of today's replacement VR's use the exotic contact materials the Delco was using back then, platinum and tungsten, if they don't that may help to explain the quick failures of new VR's that are often discussed on these Forums.
DR5134

John T · Feb 8, 2017

David, when I was a used tractor dealer and farmer doing a lot of tractor electrical repair on circa 40's through 60's genny and VR equipped tractors, many of which were Delco systems, SOME VR'S WERE CLEARLY LABELED FOR POS GROUND WHILE OTHERS WERE CLEARLY LABELED FOR NEG GROUND AND I BET DELCO DESIGNED AND LABELED THEM AS SUCH FOR A SOUND ENGINEERING REASON. It was my understanding (no warranty) it had to do with the relay contacts and their particular coatings and which contacts used what coating. Also if solid state devices were utilized within (even though still primarily a mechanical VR), its obvious why they required a certain polarity. Then it seems later years I saw some VR's that were suitable for EITHER polarity.

Sooooooooo I may be wrong but its my engineers opinion THERE IS A DIFFERENCE in VR's for use with different polarity. That being said its my best engineering guess that if there's no solid state devices used (like blocking diodes) while a VR may still "work" and the incorrect polarity, it may well last LONGER if the correct polarity VR is used.

That's my story n Ima stickin to it lol BUT NO WARRANTY IT MAY BE WRONG AS RAIN

John T Retired Electrical Engineer NEVER a designer of VR's

JMOR · Feb 8, 2017

Yes on the contact materials. One additional note, some old Chrysler products (Auto-Lite) used mechanical regulators, BUT utilized rectifiers for contact arc suppression, so those were/are polarity sensitive.

John T · Feb 8, 2017

OUTSTANDING, thanks for the informative post Bob. Pages 10 and 11 of the Delco data you linked puts to bed any question about there being a difference in Positive versus Negative Ground Voltage Regulators (there is indeed a difference) ........ I already have several Delco manuals in my digital library but its not something I set around and read daily lol

John T

David G · Feb 8, 2017

I have no problem being wrong, gives me a chance to learn something new.

Thanks

James Howell · Feb 8, 2017

Thanks for the link to the [b:654c4848f0][i:654c4848f0]STANDARD DUTY Generator Regulators manual[/i:654c4848f0][/b:654c4848f0].

pete 23 · Feb 8, 2017

Everyone who is attempting to repair or understand how a generator and regulator operates, would be very wise to read the entire article in that Delco Remy book on that link below. The part most don't grasp is that the regulator points are opening and closing all the time when they are regulating the voltage.

If believe it says up to 200 times a second they open and close. Tells you why they have to make good contact to operate properly. I was told, once upon a time that the Zenor diode used in electronic voltage regulators can open and close the circuit up to 7000 times a second, therefore much smoother regulation. No moving parts of course, all solid state.

Hank ABAB · Feb 8, 2017

Where is Dell (WA)?
I've been watching for his answer.

.................. and his sign-off signature, as in "Dell, yer self-appointed sparkie-meister "

BarnyardEngineering · Feb 8, 2017

I rank "different contact materials" as bunk right up there with the reasons given for using positive ground in the first place.

Turns out it doesn't make enough difference to matter, positive or negative ground. I believe the same goes for the contact materials in the points on the regulator.

The only reason for positive ground is "originality," and I do have a couple tractors that are 6V positive ground for just that reason.

...and if you're jump-starting, there should be no confusion. You hook + to + and you hook - to -, period.

JMOR · Feb 8, 2017

(quoted from post at 15:43:22 02/08/17) I rank "different contact materials" as bunk right up there with the reasons given for using positive ground in the first place.

Turns out it doesn't make enough difference to matter, positive or negative ground. I believe the same goes for the contact materials in the points on the regulator.

The only reason for positive ground is "originality," and I do have a couple tractors that are 6V positive ground for just that reason.

...and if you're jump-starting, there should be no confusion. You hook + to + and you hook - to -, period.

ell, everyone has an "opinion"/"belief".

2510Paul · Feb 8, 2017

Thanks. Paul

jeffcat · Feb 8, 2017

Glad to see it covers two and three relay type. Notice all 6 volt yet. Very very good PDF FILE. Thanks. One of these helps too. Almost like working with stone knives and bear skins. Mr. Spock

jeffcat · Feb 8, 2017

You bet! They kinda blow up real good. Tin foil and wax paper all over the place. Go change youre undies.

Bob M · Feb 8, 2017

Hey John T - That's exactly how an old-time EE explained it to me back in the 1960's.

Regulators were designed for a specific polarity by selection of mating contact materials. Also by the application of primitive solid state diodes (and perhaps electrolytic capacitors?) for arc suppression.

Bob M - retired mechanical engineer(!)

John T · Feb 8, 2017

Wonder if his answer will be like most of us sparky gents here and what the Delco literature indicated, IE YES VR's are indeed designed for Pos or Neg ground THERE IS A DIFFERENCE

John T

4520BW · Feb 9, 2017

My dad's D 17 is positive ground and I put a neg on it and the battery did not charge.

David G · Feb 9, 2017

That is not due to the regulator, it is because the generator needs re-polarized when you change polarity.

Polarity, am I wrong.

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