How to choose the current of AC contactor and thermal relay ?

Under the condition of satisfying the voltage level, it is selected according to the current of the load.

(1) The rated current of the contactor is greater than or equal to the actual current of the load. If the operation is frequent, the contactor should choose a larger current level.

(2) Thermal relay is used as overcurrent protection, that is, 1.1 or 1.2 times the normal load current to select the tripping current of thermal relay. The release current-time curve of the thermal relay can be viewed, and the stabilizing current knob of the thermal relay can be adjusted to obtain the best protection effect.

(3) Calculate the rated current according to the motor power to select the thermal relay, for example: 3KW = about 6A rated current, then you choose the thermal relay whose setting current is a little larger than 6A, and then choose the AC contactor accordingly.AC contactor is a kind of contactor, its typical structure is divided into two breakpoint direct drive (LC1-D/F*) and single-break rotation (LC1-B*). AC contactor and relay control circuit combination, remote control or interlocking related electrical equipment.

Uses of AC contactor: Connecting and breaking AC circuit, can play a remote control, motor forward and reverse control.