When choosing a motor, how to choose power and torque?——Part one

(Part One)

The power of the motor should be selected according to the power required by the production machinery, and try to make the motor run under the rated load.

When choosing, you should pay attention to the following two points:

① If the motor power is too small. There will be a phenomenon of "small horse-drawn cart", causing the motor to be overloaded for a long time. Its insulation is damaged due to heat. Even the motor was burned out.

② If the motor power is too large. There will be a "big horse-drawn cart" phenomenon. Its output mechanical power cannot be fully utilized, and the power factor and efficiency are not high, which is not only unfavorable to users and the power grid. And it will also cause waste of electricity.

To correctly select the power of the motor, the following calculations or comparisons must be made:

P=F*V/1000 (P=calculated power KW, F=required pulling force N, working machine linear speed M/S) For constant load continuous working mode, the required motor power can be calculated as follows: P1 (kw ): P=P/n1n2 where n1 is the efficiency of the production machinery; n2 is the efficiency of the motor, that is, the transmission efficiency. The power P1 obtained by the above formula is not necessarily the same as the product power. therefore. The rated power of the selected motor should be equal to or slightly greater than the calculated power.