Compared with ordinary motors, there is not much difference in appearance between frequency conversion motors and ordinary motors, but there is a big difference between the two in terms of performance and use. The frequency conversion motor is powered by a frequency conversion power supply or a frequency converter. The speed of the motor can be changed. There are constant torque and constant power frequency conversion motors, while the ordinary motor is powered by the industrial frequency power supply, and its rated speed is relatively fixed. The fan of the ordinary motor rotates with the rotor of the motor at the same time. In the frequency conversion motor, another axial fan is used for heat dissipation. The rotation speed of the extension is fixed, which can ensure the heat dissipation requirement of the motor when the motor is running at low speed. Therefore, when ordinary fans are used with frequency conversion and running at low speeds, they may burn out due to overheating.