Motor winding temperature change due to the passage of operating time We will introduce the temperature rise of the motor winding when actually driving the motor. Our AC motors will not burn out if the motor case temperature is below 90° C. The guidelines for each heat resistant class are summarized in the table below. During operation, be careful not to exceed the winding allowable temperature.Īs the winding temperature inside the motor can not be measured directly, measure the surface temperature of the motor case as a reference.įor our AC motor, the temperature difference between the windings and the motor case is up to 30 ° C. Also, if not burned, the temperature rise affects the motor life. If the internal temperature of the motor exceeds the heat class value for a while, the winding ﬁlm melts and shorts. Classiﬁcation varies from series to series. Our AC motors are classiﬁed as either Class E (120° C) or Class B (130° C). The heat resistant class is a classiﬁcation based on the heat resistant grade of the insulating material. Motor temperature rise affects the operating time limit and motor life. Electrical energy is not 100% converted to power, and some energy is lost (heat). Temperature Rise and Heat Resistant Class of AC Motor Electrical Energy Conversion and LossĪn AC motor is an energy conversion device that converts input electrical energy into power for rotation and outputs it. Download PDF Temperature Rise and Life of an AC Motor 1.

Typical ac motor winding resistance