When choosing AC contactor, the working voltage of AC contactor shall not be lower than the maximum voltage of the controlled circuit, and the rated current of the main contact of AC contactor shall be greater than the maximum working current of the controlled circuit. When using AC contactor to control motor, the maximum current of motor should not exceed the allowable rated current of AC contactor. When used to control reversible running or frequently starting motors, AC contactors should be increased by one to two stages. The rated voltage of the electromagnetic coil of AC contactor is the same as that of the controlled auxiliary circuit. For simple circuits, 380V or 220V are often used; for complex circuits or occasions with low voltage power supply or special requirements of working environment, 36V or 127V can also be used.
Usually, the installation orientation of the contactor is specified, and the inclination of the contactor should not exceed 5 degrees. In case of emergency use, when this requirement is not taken into account, it is advisable to check its action and release before it is officially used after installation. In addition, when determining the installation location, the convenience of inspection and maintenance in the future should also be taken into account. It is worth noting that the working environment of AC contactor should be clean and dry, and its installation position should not be subjected to severe vibration, so as to avoid contact jitter and misoperation.