1. The choice of the principle of AC electric motor
In order to accommodate a variety of uses, electric motor manufacturers can produce different types, structure type and
capacity of three phase asynchronous motor and synchronous motor. In the selection of AC electric motors, to fully consider their characteristics, carefully studied the characteristics of the driven machinery and equipment, select the load characteristics of the motor.
The principle of selecting the ac electric motor is:
1) According to the starting characteristics of the load and operating characteristics, select the most suitable for these characteristics of the motor to meet the production machinery in the process of the various requirements. 2) A motor having a protection class and a cooling method suitable for use in an environment of a place of use should be adapted to the environmental conditions in which the motor is located.
3) Calculate and determine the appropriate motor capacity. Usually designed and manufactured motor, the 75% -100% rated load, the highest efficiency. Therefore, the capacity of the equipment should be the smallest and the difference in the capacity of the selected motor, so that the power of the motor can be fully utilized.
4) select the high reliability, easy to maintain the motor.
5) taking into account the interchangeability, try to choose the standard motor.
6) In order to make the whole system run efficiently, consider the number of poles and the voltage level of the motor.
2. The general steps to buy an AC electric motor can be considered as follows:
1) According to the requirements of the production of mechanical, select the motor type. Such as asynchronous motor include squirrel cage induction motor, slip ring induction motor, variable frequency motor, brake motor.
2) Depending on the power supply, select the motor rated voltage.
3) According to the number of revolutions required by the production machinery and the transmission equipment, select the number of revolutions of the motor.
4) According to the motor and production machinery installation location and place environment, select the motor structure and protection form.
5) According to the load required by the power capacity and the motor running mode, select the rated power of the motor.
In the selection of ac electric motor, to take into account the above factors, and communicate with the electric motor manufacturer to select the most suitable motor.
