1. Contactor is the component of the main circuit, used for the switch of connecting and disconnecting in the main circuit, relay is the component of the auxiliary circuit, used for control, signal transmission and amplification, etc.
2. The contactor needs to bear the impact current while breaking and closing, so the overload ratio of the contactor can reach 8 to 10 times; The current of the relay control generally does not have the impact, so the overload ratio of relay contact is generally twice times;
3. The contactor has the ARC extinguishing device, the relay does not have;
4. Contactor and relay of the electromagnetic system all are constant magnetic potential, but the contactor generally only is with voltage coil, and some relays have multiple coils, such as voltage coil and current coil. The current coil is used for actuation and the voltage coil is used for holding;
5. Contactor coil will be equipped with RC absorber; the relay generally doesn’t have;
6. The contactor belongs to the main circuit element, so its contact system has thermal stability parameters and dynamic stability parameters, and the relay doesn’t have;
7. The contactor conductive rod tin plated nickel is used for improving the temperature, and the conductive rod of the relay is plated with tin for improving the conductivity.