The analogy can also be used to select the power of the motor. The so-called analogy. It is compared with the power of a motor similar to that used in production machinery. The specific method is to know how much power the similar production machinery uses in this unit or other nearby units, and then use a similar power motor for the test. The purpose of the test run is to verify that the selected motor matches the production machine. The verification method is to make the motor drive the production machinery, measure the working current of the motor with a clamp-type ammeter, and compare the measured current with the rated current marked on the motor nameplate. If the actual working current of the electric machine is not much different from the rated current indicated on the spleen, it indicates that the power of the selected motor is appropriate. If the actual operating current of the motor is about 70% lower than the rated current indicated on the nameplate, it means that the power of the motor is too large (ie, the "large horse-drawn car" should be replaced with a motor with a lower power. If the measured motor works The current is more than 40% larger than the rated current marked on the nameplate. It indicates that the power of the motor is too small (ie "small horse-drawn cart"), and the motor with higher power should be replaced.