In actual work, we divide the solid state relay into two types according to the load, one is the inductive load, and the other is the resistive load. The most common inductive load is the motor.

Common heating elements, thermocouple incandescent lamps are resistive loads. When the two start up, the instantaneous current is different. When the resistive load starts, the instantaneous current is generally 1 times normal, and the inductive load is generally 6 times that of normal startup.

Most electricians often use solid-state relays to drive the motor load, which often causes damage to the contactor. It is important to choose a solid-state switch based on the load.

The shape of the solid state relay is different from that of the contactless contactor, because the solid state switch generates more heat. The ordinary solid state relay is used for the resistive load without considering heat dissipation. After all, the instantaneous current is only doubled, and the contactless contactor is used for With a motor, the load has a high heat dissipation, which requires more considerations in heat dissipation and circuit design.