Starting Method of Electric Motor Pump
Star Delta Starting Method：
Star Delta Starting Method has simple structure, low price and high reliability. Therefore, it is widely used to start by reducing the startup current of equipment by reducing power. Current characteristics are good, but torque characteristics are poor, so objective existence is only applicable to no-load or light-load starting occasions.
Auto-decompression starting Method:
The starting type of autotransformer step-down is to reduce the startup voltage applied to motor stator windings by using autotransformer. When the motor is started, the motor is separated from the transformer so that it can move normally under full voltage. This step-down start can be divided into manual control and automatic control. The different taps of the autotransformer can be selected according to the allowable starting current and the required starting torque to realize step-down starting, and the stator winding of the motor can be used by Y or_connection method.
Soft Starting Method :
Soft start is to realize smooth start of motor and mechanical load by means of step-down, compensation or frequency conversion, so as to reduce the impact of starting current on power grid and protect power grid and mechanical system. This form has high cost but good protection for equipment. Voltage is gradually raised from zero to rated voltage, so that the starting current of the motor in the starting process can be controlled from the uncontrollable overload impulse current in the past. The starting current can be adjusted according to the need.
Direct Starting Method:
Direct-start Method is generally considered for pumps under 15KW, and the starting load is not more than 20% of the capacity. The restriction is large and the actual use is relatively small.