Polarizing Generators on C1 1956-1962 Corvettes

A Polarizing Topic

Polarizing the 1953-1962 Corvette Generator


I enjoy reading Vette magazine cover-to-cover each month. I own a fuelie 1958 Corvette and my problem is that the battery is not charging. I tested the system and determined the generator was charging so I replaced the voltage regulator and the car is still not charging.

I was talking to a friend that has an early Corvette and he said he had to have his generator polarized. This sounds like some witch doctor voodoo to me.

All of the research about this just seems confusing. Do I need to polarize the generator?

I was also going to install a battery disconnect switch on the battery because some of my research found there has been cases of the voltage regulator sticking, causing the vehicle to catch on fire and burn. If I install a battery disconnect switch, will I need to polarize the generator every time I reconnect the battery?

Thanks for your help.



Jim, polarity is the direction of a magnetic or electrical field. For the generator to charge correctly the armature must have the correct polarity in relation to the field coils.

Let me start with what I hope is a simple explanation of polarization. The polarity of the generator must be set to match the polarity of the voltage regulator. Polarization is a procedure that matches the polarity of the generator and that of the voltage regulator to make sure they are working and charging the same. In other words, making sure the generator and voltage regulator are working together and not against each other.

Vehicles using generators could use a positive or negative ground. However, all Corvettes, whether they have a 6-volt or a 12-volt system, use a negative ground, but sometimes we need to remind our Corvette that it is using a negative ground.

When you polarize the generator to the voltage regulator you are making sure that the generator and voltage regulator are both using the same ground.

The generator uses permanent magnets that can lose their magnetism, especially if the vehicle is stored for long periods of time. The generator is self-exciting and needs no external current to produce a charge. You are re-magnetizing the magnets and setting the correct polarity when you polarize your generator.

You may need to polarize your generator whenever any of the following services are performed:

• The generator is replaced or repaired.

• The voltage regulator is replaced or repaired.

• The battery is replaced or disconnected from the vehicle. Most of the time using a battery disconnect or replacing the battery will not affect the polarization of your vehicle. You should test your charging system after a battery replacement or after the first few times you use a battery disconnect to see if either of these affect the vehicle’s polarization.

It’s possible—but not probable—for the vehicle to lose its polarity for no apparent reason and need to be polarized again, especially if the vehicle is stored for long periods of time.

How to Polarize the Generator and the Voltage Regulator
This is a relatively simple process and is done by permitting a surge of current to flow through the generator, correctly polarizing it. The following process is for a 6-volt or a 12-volt negative ground system.

You will need a 16-gauge wire approximately 12 inches long.

The battery will need to be fully charged.

The engine is not to be running.

Polarize the generator by momentarily connecting a jumper wire between the “BATT” (Battery) terminal at the voltage regulator and the “ARM” or “A” (Armature) terminal at the generator for approximately one second or until you see a brief spark. (Do not hold this jumper wire for more than one second).

This will allow a momentary surge of current to flow through the generator, which will correctly polarize it.

Jim, if you do not polarize the generator there is still a 50/50 chance it will work correctly, but if your vehicle is not polarized correctly, damage to electrical components can occur. Good luck and let me know how everything works out. Vette

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