Topic: polarizing generator


dcgriff    -- 05-21-2015 @ 7:10 PM
  I always polarize the generator on my bikes that have 2 brush generators and voltage regulators. Should I also polarize the generator on my '46 Ford - 2 brush generator, voltage regulator and positive ground? The workshop manual doesn't mention this.


42wagon    -- 05-22-2015 @ 3:34 AM
  According to an old handbook I have the generator needs to be polarized.

"When installing a generator it must be polarized so that current flow will be in the proper direction, otherwise arcing will occur at the cutout points. To polarize a generator, momentarily connect a jumper wire from battery terminal to the "F" or field connection on the generator before connecting the field wire"


MICHV8    -- 05-22-2015 @ 3:42 AM
  Hmmm...assuming a positive ground system, which battery terminal would that be?


42wagon    -- 05-22-2015 @ 4:05 AM
  The book doesn't say but I'm going to say negative since you will be connecting the "F" terminal to the positive ground anyway with the permanent wiring.


TomO    -- 05-22-2015 @ 6:21 AM
  Unless the generator has been hooked up backwards, you should not have to polarize it. The best practice is to disconnect the battery before installing a generator or regulator.

To Polarize a generator with a regulator, disconnect the field wire from the regulator and touch it to the Battery terminal of the regulator. You will need to do this if the ammeter shows a discharge when you increase the RPMs, or the generator is not charging.

Tom

This message was edited by TomO on 5-22-15 @ 8:13 AM


42wagon    -- 05-22-2015 @ 6:48 AM
  There seem to be some misconceptions here. Go to Google and type in "polarizing a 6 volt generator" You will find that it is advisable to polarize the generator anytime you remove the battery,generator, or regulator. Google states that it should be done by attaching a wire to the field terminal on the generator that is long enough to reach the negative terminal on the battery. You are to touch the wire to the terminal very briefly and that will polarize the generator.

This agrees with the old Ford service manual I have.


TomO    -- 05-22-2015 @ 9:36 AM
  42Wagon,

I have gone through the Service Bulletins, the reprint of the 39-48 Service Manual, the 49-51 Mercury Overhaul Manual and the Lincoln Mercury Master Check and have found NO reference to polarizing the generator or regulator. The procedure that I quoted came from a replacement voltage regulator and was to be used only if the generator did not charge after replacement.

Could you please let me know which Ford Service manual that you found this in?

If you had to polarize the generator to the regulator every time that you disconnected the battery, I would have to do this every time I wanted to use one of my cars with a generator, as I disconnect the battery when I park them for the night.

Tom


42wagon    -- 05-22-2015 @ 12:01 PM
  Tom
I'm not going to get into an argument with you on this subject. In my first response I quoted directly from a book that has been on my shelf for sometime titled The Ford Owner's Complete Handbook of Repair and Maintenance. by William J. Lipsett and published by Floyd Clymer in 1949. The book says it covers all models from 1932 thru 1949 including V8, "60", and Ford 6. You will note the quote only says "when installing a generator" nothing about the battery or regulator. The inference being that you might have taken apart and reassembled the generator or someone else has.

The other item I quoted is directly off of Google when you type in "polarizing a 6 volt generator". This is where the discussion of the battery and regulator comes from.

I make no claim for the validity of doing this but it is in the book. You will also note the the original question was from dcgriff who says he has always polarized generators on his motorcycles and wondered why no one was suggesting doing it for the same type generator on Fords. You may do what you wish, I will continue to polarize my generators whenever I take them apart.


cliftford    -- 05-22-2015 @ 7:50 PM
  Back in the day most non dealer repair shops used Motors or Chilton repair manuals for most repair work. Mitch*lls manuals may have been available, but I do not recall having them. Anyway as I recall. both manuals recommended polarizing the generator when any gen. or regulator work was done. It was standard practice.


dcgriff    -- 05-22-2015 @ 9:10 PM
  I appreciate everyone's input on this subject. From the info, I'm surmising that it certainly won't hurt to polarize the generator.
What's weird is that the generator seems to be working - the headlights dim a bit at idle, then brighten as soon as I step on the gas, however the battery doesn't charge. I installed a new 6V battery and new regulator. I drove the car about 6 miles with the headlights on and checked the headlights as above, and shut the car off. I tried to restart it right away and just got that rattling solenoid. The battery had a full charge when I first started it and it seems amazing that it would fully discharge in 6 miles, even with the headlights on.


TomO    -- 05-23-2015 @ 7:37 AM
  You will not damage anything by polarizing the generator.

If your battery was connected with the NEG post gong to ground, and then connected with a POS ground, you will need to do this. Your battery should be connected with the POS terminal going to ground.

Before you do this, connect your volt meter with the COM or black lead to the BAT terminal of the voltage regulator and the POS or red lead to ground. Start the engine and increase the RPMs to about 1,500 RPM and read the meter. It should read 7.2 to 7.4 volts. If it reads a negative voltage, you will need to polarize the generator.

Let us know the results and if you still have a problem, post it here and I can give you some more tests to check out your charging system and battery.

Tom


dcgriff    -- 05-23-2015 @ 6:41 PM
  Well that was a big help. After fully charging the battery, I tested the voltage as you described and had the same voltage that I had across the battery terminals, about 6.7. When I turned on the headlights voltage went to 6.1.

So I removed the new regulator and replaced it with the rusty old regulator that was on the car for God knows how long, and voltage went to 7.2 +. Even with headlights on it only dropped to about 7.

I drove about 15 miles with the headlights on and shut the car off. Motor turned over great and started right up.

So, at this point, all seems to be well
Many thanks for your advice.


TomO    -- 05-25-2015 @ 7:19 AM
  I am glad that you solved your problem.

The 39 and 40 Fords and Mercurys had a voltage gauge in the instrument panel and i have always liked that better than the ammeter in the other years. I still have a hard time determining if my battery and generator are working correctly with an ammeter.

Tom


LazarusLong    -- 05-26-2015 @ 8:51 PM
  Sounds like the points in your new regulator may be sticking. Take the cover off and file them with a finger nail file,and then start the car up while the regulator cover is still off so you can see if the points are opening and closing.

You can even adjust at least some of the regulators to put out a little more charge if you want.

You either need two people to do this so someone is watching the amp gauge inside the car as you adjust the points,or you need a amp gauge connected at the battery so you can see what is happening as you work.


TomO    -- 05-27-2015 @ 7:33 AM
  Using the amp gauge in the car to adjust a voltage regulator could lead to damaging the generator. The proper way to adjust them is to check the voltage at the regulator with a precision voltmeter and a 0.75 ohm resister.

The inexpensive digital meters sold today are so unreliable as to their readings, that I would not want to use one for any reading except to see if voltage is present.

If your regulator needs adjustment and you do not have an USA made precision voltmeter like a Fluke, take the regulator to a generator repair facility and have it adjusted there.

Tom


dcgriff    -- 05-27-2015 @ 7:01 PM
  Since installing the rusty old original regulator, I've put about 100 miles on the car an the motor turns over, starts and runs like new. You're spot on about cheap digital volt meters but with my trusty old needle style VOM and your advice on how to test the regulator output I was able to ascertain that the old regulator was working. We have a good generator shop here if I need any fine tuning with the charging system, but I'm leaving everything just as it is for now.
Rust is good!


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