The electromagnetic contactor is a mechanical switching device controlled by an electromagnet. When the coil of the electromagnet is energized the contactor closes its main poles, establishing the circuit between the electrical supply and the load being controlled (motor, etc.). Due to its design the contactor represents a convenient and versatile way of controlling power switching. The coil of the contactor is available in both a.c and d.c control voltages.



Control relays are devices which are derived directly from the technology used in power contactors. The difference is essentially in the replacement of the poles by auxiliary contacts which have a conventional thermal current of 10A. This mutual design and presentation identity enables system panels to be assembled in a common fashion.



A range of contactors and relays are available up to several 1000 amps from a number of major manufacturers.


Overload Protection

The bi-metallic thermal overload relay is the most widely used in industry and provides a high level of protection against small or prolonged overload conditions.

They may be used on a.c or d.c systems and generally feature:

  • Three pole operation and protection
  • Ambient temperature compensation, so that temperature fluctuations do not affect their overall performance
  • Single phase protection, this prevents the associated motor running in a single phase condition
  • Manual or automatic resetting
  • A graduated scale in “motor FLC” thus allowing the relay to be set according to the “full load current “ as shown on the motor plate.

Choose a manufacturer to see the full range available:
Schneider Motor Control ABB Contactors
Lovato Products IMO products