The ZORC is a unique high frequency transient surge suppressor intended for the protection of motors, transformers and generators against steep wave front, short rise times, large amplitudes, spikes, surges, other voltages transients and circuit switching.

Main characteristics

  • Reduces costs by eliminating production downtime due to switch isolation failure
  • Protects motors, generators and transformers throughout their useful life
  • Eliminates multiple pre- and re-striking of no-load transients and associated with other equipment
  • Standard and intrinsically safe models available
  • Three phase and single phase

Product Features

  • System voltage: 400 V to 40 kV
  • Transient protection: 0.1 to 0.2 microsecond interval
  • Special compact versions that can be installed in most motor/transformer terminal boxes or switchgear panels


  • Fans
  • Compressors
  • Crushers
  • Motor generator sets
  • Conveyors
  • Generators
  • Induction and arc furnaces
  • Pumps
  • Mills
  • Refrigeration machines
  • mine reels
  • Mini and mobile substations
  • Power station auxiliaries
  • Dry type transformers


ZORC surge suppressors can be installed in any direction (including upside down) on the machine side of the associated medium voltage motor/generator/transformer switch, in the following positions (in order of priority of point of view of surge protection).

Preferred Connections of ZORC Surge Suppressors

  • In motor/generator/transformer terminal box, connected from each phase to ground
  • Wired to the motor/generator/transformer terminal box via a three-core cable (25mm minimum), in addition to an earth conductor (according to local regulations)
  • In line with the motor/generator/transformer power cable, the shunt is connected from each phase to ground
  • In the associated motor/generator/transformer switchgear panel, connected from each phase to ground
  • Convenient mounting brackets or flanges are provided

Overall mechanical dimensions – guide:

The ZORC surge suppressor is a unique voltage and frequency dependent hardwired termination network comprising capacitors, resistors and non-linear zinc oxide (ZnO) arresters.