Part of the rated current of the inverter is less than the rated capacity of the motor current, should be based on the load of the motor to consider the choice of large-scale inverter 02 The motor may be overloaded for a short time because the so-called "short time" of the motor is relative to the heating time constant. Just a few minutes, as many as a few minutes. The inverter overload capacity, usually 150%, 1min. Compared with the motor, is equal to no overload capacity. Therefore, if the motor may be overloaded in the think tank time, the capacity of the inverter should be increased. 03 The acceleration and deceleration time has a special requirement for the length of the motor acceleration time is a relative concept of inertia size. For example, the acceleration time is 5 s, which may be too short relative to the load with a large inertia (GD2), but may be too long relative to a load with a smaller inertia (GD2). In general, it is important to consider increasing the capacity of the frequency converter in the following cases for loads that need to be started and stopped during heavy loads: (1) require quick start and stop; (2) move more frequently. 04 For example, the motor and the load are combined by a clutch. Usually in the motor has been rotating up the state, due to the combination of the clutch, so that the load is also rotating. Obviously, in the moment the clutch just joined, the motor speed will drop, the slip increases, the current also increases, may lead to over-current protection action. In this case, the capacity of the inverter should be increased.