The rewind of an industrial electric motor can often be an effective cost measure for a customer. When excessive heat causes damage or failure of a motor’s insulation system, there is no need to run out and buy a new motor. Motor rewinding gets the motor back in good working order without the high cost of paying for a new one.
After a motor is rewound using new copper windings, a varnish is applied to the motor. This is called dip and bake process. For larger purpose built motors, another process may be used, known as Vacuum Pressure Impregnation or VPI. The stator (the stationary part of the motor) and the coil assembly (the electrical aspect of the motor) are submerged into a tank of varnish. The varnish is absorbed, fills in the voids and slots in the windings and keeps out other debris from the windings. When the VPI process is used, the varnish is forced into the windings under pressure to accomplish the same thing. After the motor is varnish treated and baked (so the varnish cures), it is electrically tested before reassembly and delivery to the owner.