Why can't ordinary motors be used as variable frequency motors?

Ordinary motors are designed based on constant frequency and voltage, and cannot fully meet the requirements of frequency converter speed regulation. Therefore, they cannot be used as variable frequency motors.

The difference between variable frequency motors and ordinary motors is mainly manifested in the following two aspects:

Firstly, ordinary motors can only operate for a long time near the power frequency, while variable frequency motors can operate for a long time under conditions that are severely above or below the power frequency; For example, the power frequency in our country is 50Hz. If an ordinary motor stays at 5Hz for a long time, it will quickly malfunction or even be damaged; The emergence of variable frequency motors solves this deficiency of ordinary motors;

Secondly, the heat dissipation systems of ordinary motors and variable frequency motors are different. The heat dissipation system of a regular motor is closely related to its speed. In other words, if the motor rotates fast, the heat dissipation system will be effective. If the motor rotates slowly, the heat dissipation effect will be greatly reduced, while variable frequency motors do not have this problem.

After adding a frequency converter to a regular motor, it is possible to achieve variable frequency operation, but it is not a true variable frequency motor. If it works in a non power frequency state for a long time, it may cause damage to the motor.