How do you polarize a dynamo?

Answer 1

Polarizing or repolarizing a dynamo is a way to wake up generators that may not have been used for a longtime, may have been incorrectly wired up in the past, or are not producing any voltage for some reason. First thing to check is which battery terminal is connected to the frame or chassis of the vehicle. Modern cars & motorcycles have the negative terminal connected to the frame, this is called a negative earth configuration. For models of the 1950s and earlier, the configuration is positive earth. To polarize the dynamo for negative earth, disconnect the positive or live wire from the battery terminal at the same time making sure the negative terminal is connected to the chassis. Disconnect the wires from the D and F terminals of the dynamo and run a wire from the positive terminal of the battery and brush the other end of this wire over the F terminal 2 or 3 times until a blue spark can be seen. The dynamo is now polarized for negative earth. Do the procedure in the other way around to polarize a dynamo for positive earth.