Why Can't The Micro Motor Be Used As A Variable Frequency Motor?

In the drive of electric products, micro DC motors are used to realize various functions. Common micro DC motors and variable frequency motors are commonly used in motor applications. Why can't ordinary micro DC motors be used as variable frequency motors? Below is a brief answer to the reasons.

The frequency converter carrier generally has several kilohertz, the winding of the micro motor will withstand the voltage rise, and the inter-turn insulation of the micro motor cannot bear it. The use of inverter power supply for micro motors will lead to abnormal electromagnetic and mechanical vibration and noise. Because the harmonics of the variable frequency current and the inherent space harmonics of the electromagnetic part of the micro motor interfere with each other, various electromagnetic excitation forces will be formed to increase the noise of the micro motor. The working frequency range of the micromotor is wide, and the range of rotation speed is relatively large, so it is difficult for various electromagnetic force waves to avoid the natural vibration frequency of each structural part of the micromotor.

Ordinary micro motors are designed according to constant frequency voltage, and cannot fully meet the speed regulation requirements of frequency converters, so they cannot be used as frequency conversion motors. The frequency converter affects the efficiency and temperature rise of the micro motor. The wave voltage and current cause the micro motor to run under non-sinusoidal voltage and current. The higher harmonics will increase the losses of the micro motor's stator and rotor. These losses will cause the micro motor to generate additional heat and reduce the efficiency. , The output power is reduced, and the temperature rise of ordinary micro-motors will increase by about 10%-20%. The heat of the micro motor cannot be dissipated, the temperature rise increases sharply, and it is difficult to achieve constant torque output.