Main features & Overview


The GD series of solid state relays (zero crossing type) are solid state actuators with heater break diagnostics (Hb function), selectable current scale, and adjustable setpoint. Junction overheat protection is available as an option.

An alarm signal is provided in output. The GD series of solid state realays are offered with currents of 40A, rated voltage 480 Vac, and Vdc input control signal.

Voltage transistors are protected by MOV (varistor).

See the dissipation curves for other performance conditions.

The GD series of relays must be used with an appropriate heatsink. Thanks to their high performance, they are appropriate for very short switching times, with millions of operations without wear on components.

Various accessories are available, such as heatsinks, fuses and fuse holders.


Zero-voltage switching. Current range: 40A, diagnostics and load interrupt alarm

  • AC solid state relays with logic signal control
  • Switching at voltage zero crossing
  • Built-in heatsink o Rated current: 25Arms, 40Arms
  • Non-repetitive voltage: 1200 Vp
  • Rated voltage: up to 530VCArms
  • Input control range: 5…30 Vdc
  • Optical isolation: 4000Vrms (input/output)
  • Built-in HB diagnostics (partial heater break, junction in short circuit)
  • Overheat protection (optional)
  • 2-color control signal LED in input/alarm state
  • On-board MOV (varistor)


Gefran product range brochure
Power control
GD datasheet
Installation and Operation Manual


UK Conformity declaration - GD