1, only through the motor model to determine, the general motor nameplate are given;
2, through the external power to determine. If the three-phase power must be AC, if the DC battery and other DC power is connected to the DC motor;
3, now generally AC motor, DC motor is very small, and are smaller capacity of the motor. There are many DC motors in the power plant, because the DC power supply of the power plant is very reliable (the power plant has a special DC system power supply), and the civil direct current motor is very few, because the DC power supply is not easy to obtain.