Method for Selecting Motor Power

The principle for selecting the rated power of an electric motor is that the selected rated power must meet the power and torque requirements of various stages of production machinery in drag (starting, speed regulation, braking, etc.), and on this basis, the motor can be fully utilized. The method for selecting the rated power is to pre select the rated power of the electric motor based on the characteristics of large and small changes in load (torque, power, current) during the operation of the production machinery, Then verify the overload capacity and starting capacity based on the rated power of the selected motor.The rated power of a motor is determined based on whether the temperature rise of the motor during operation does not exceed the allowable temperature rise of the insulation material. The variation pattern of temperature rise is related to the working characteristics, and the rated power of the same motor varies under different working conditions.

 The rated power PN of an electric motor refers to the maximum mechanical power that can be continuously output by the motor at a standard ambient temperature (40 ° C), under a specified working system and rating, to ensure its service life. If all actual conditions are the same as the specified conditions, as long as the rated power PN of the motor is greater than the actual power P of the load, the actual steady-state temperature rise w achieved during motor operation will be approximately equal to the rated temperature rise N, which can not only fully utilize the heating conditions of the motor but also enable the motor to reach the specified service life. However, the actual situation and the specified conditions are often inconsistent. On the premise of ensuring that the motor can reach the specified service life, if the actual ambient temperature is different from the standard ambient temperature, the actual working system is different from the specified working mode, the actual short-term quota is different from the specified short-term quota, and the actual intermittent quota is different from the specified intermittent quota, then when selecting the rated power PN of the motor, The rated power PN of the motor can be corrected first, so that the rated power PN of the motor is less than or greater than the actual load power P. LL

Correction of motor rated power

Selecting the motor in this way will not result in insufficient utilization of the heating conditions of the motor due to excessive selection of rated power PN, nor will it cause overload operation of the motor and shorten its service life or even damage due to excessive selection of rated power PN. When a continuous duty motor operates under the continuous duty system and the actual ambient temperature is not equal to 40C, the corrected value of the rated power of the PN motor is 40PP1 (k1) P (7-10). In equation N-rated temperature rise k-loss ratio, that is, the ratio of constant loss to variable loss, can be calculated using equation (7-10) to calculate the rated power of the motor at actual ambient temperature PN. Obviously, at 40 ° C, PP; At 40 ° C, according to theoretical calculations and practice, the rated power of the motor increases or decreases accordingly when the ambient temperature varies.

Our main products are Asynchronous Motor，The Electric Furnace Blower Motor ，Radiator Fan Motor,Indoor Blower Motor ,Single Phase Blower Motor,iron-shell single three-phase asynchronous motor series, aluminum-shell single three-phase asynchronous motor series, fan special motor series,frequency conversion motor series, permanent magnet DC motor series, etc.