First, using a non-contact infrared thermometer, or a multimeter temperature measuring baffle (a multimeter with temperature measurement, measuring the temperature of the end cover of the motor above 25 ℃ above the ambient temperature), indicates that the temperature rise of the motor has exceeded the normal range. The temperature rise of general motor should be below 20 ℃.
In the maintenance practice of fat tire electric bike, the method to deal with the heating fault of the motor is generally to replace the motor.
The direct cause of the motor’s heating is the large current. Motor current I, input electric potential E1 motor, sense of rotation of the motor electromotive force (also called back EMF) E2, and the relationship between the motor coil resistance of R is: i= (E1-E2), R.
The increase of I indicates that r becomes smaller or E2 decreases. The decrease of r is usually caused by short circuit or open circuit of coil. E 2 decrease is usually caused by demagnetization of magnetic steel or by short circuit or open circuit of coil.