The choice of household AC contactor

Choose the type of AC contactor, based on the load type as the main basis for the selection of AC contactor. According to the main circuit parameters, determine the rated working voltage, rated working current, rated making and breaking capacity, and overload tolerance of the AC contactor. Determine the coil voltage of the AC contactor according to the control circuit parameters and the auxiliary circuit parameters. Select the contactor of the relevant series or special specifications according to the surrounding environment of the place of use.

For example, the compressor motor main circuit, suppose its compressor motor is 15KW, the power factor is 0.9, and the rated efficiency is 0.85. Then the rated current of the motor IN=15×10^3/1.732×380×0.85×0.9=30A can be calculated. Therefore, the choice of AC contactor; CJ20-40A/380V, its coil voltage is 380VAC.

When selecting a contactor, the rated current of the moving contact of the household AC contactor should be determined according to the rated current of the load. If there is a phenomenon of a small horse-drawn car, it will shorten the service life of the contactor. Also select the voltage required by the coil of the contactor according to the voltage of the control power supply.