Jerry Roepke is field service trainer at Danfoss Drives, 8800 West Bradley Road, Milwaukee, WI 53224, 800-621-8806, Fax: 414-355-6117,, What's a Megger?Megger stands for meg-ohm meter. The meter has a voltage charge that is generated and then takes a meg-ohm reading of the insulation at the voltage of the generated field to earth ground.This type of reading gives the technician an indication of the relative strength of the insulation in meg-ohms at applied voltage of the meter - the smaller the number, the weaker the insulating properties of the wire to ground.High meg-ohm readings indicate a good insulating factor of the motor, and very low readings indicate a motor that is about to allow electricity to leak to the ground of the frame.