What Performances Of The Motor Will Be Affected By The Power Frequency?

What Performances of the Motor Will Be Affected by The Power Frequency?

Frequency is an important performance parameter for the normal operation of the motor. The power frequency motor matches the power frequency power supply, so there will be no situation where the power frequency does not match; however, in order to solve the starting problem of the motor, it may be started through a frequency converter, and then run in the power frequency band.

For inverter motors, the output parameters of the motor operation process will be controlled through the inverter. For example, when the output frequency of the inverter is lower than the basic frequency, the motor is in a constant torque output state; when the output frequency of the inverter is higher than the basic frequency, the motor is in a constant power operating state; therefore, regardless of whether the motor is in a high-frequency or low-frequency operating state, constant torque or constant power ensures the safety of the motor operation, especially the independent fan supporting the inverter motor, which ensures the heat dissipation requirements of the motor during operation at different frequencies; in the practical application process of the motor, the operating frequency of some inverter motors is relatively fixed, and the motor designer can also determine the motor as its own according to the actual operating characteristics. Fan-cooled structure.

For motors operating at power frequencies, the ventilation and cooling structure of the motor is autonomous heat dissipation, that is, the inner fan or outer fan hood structure coaxial with the rotor operates autonomously to dissipate heat; when the power supply frequency is reduced, the motor will have serious consequences of winding heating or even burning due to unsatisfactory heat dissipation conditions; at the same time, when the output power of the motor remains unchanged, due to the decrease in the motor speed, the motor's transfer torque will increase, and the motor's shaft, bearing and other structural parts may have hidden quality risks.

And when the power supply frequency is high, if the torque of the motor is not adjusted, because the increase in speed will cause the motor power to increase, the corresponding current will increase, once the rated current is exceeded, the winding of the motor is in danger of heating and burning.

Therefore, the other input parameters of the motor remain unchanged, and the power supply frequency is simply adjusted. The motor faces torque overload at low frequencies and current overload at high frequencies. If the abnormal frequency running time is short, the motor may not have problems, but when the abnormal frequency running time is long, the motor is very likely to have serious mechanical or electrical failures.