Three Phase Solid State Relay

Three Phase Solid State Relays – 7300S

Product Description

A range of three phase solid state relay, three leg solid state contactors for use with short wave infrared (SWIR) and Low Temperature Coefficient resistive loads.

  • Current range from 16 to 160 amps at 45°C
  • Voltage up 500V
  • Inputs: Logic (AC or DC) or Analogue 4-20mA which gives time proportional output
  • Suitable for SWIR or resistive loads
  • Over-temperature shutdown for fan cooled units (over 100A)
  • Thyristor short circuit alarm
  • Over-temperature alarm
  • Diagnostic load failure detection

These units, with integral heat sinks, are driven by either DC or AC Logic signals.  Also an analog 4-20mA input can be specified which gives a linear time proportional output.


In all cases the output is zero voltage switching. High speed fuses are mounted external to the unit for 100 amps and below, internal above 100 amps. They can be ordered as part of the 7300S order code. Spare fuses or complete fuse and fuseholder assemblies can also be ordered separately.

Limits and Alarms

The 7300S has an optional thyristor short circuit and total load failure alarm.

An over-temperature shut down is provided for fan cooled units (over 100 amps). An optional over-temperature alarm is also available.

Diagnostic Load Failure detection is an option which alarms on the loss of one or more parallel heating elements (resistive or SWIR). The sensitivity is maximum one out of four. It is auto-setting via a front panel push button.

Digital Communications

The Modbus communications option allows digital control of the unit, interrogation of the alarms, firing status.