NT133-3 Temperature Controller

The NT133-3 temperature controller is simple, and easy to operate but still provides a wealth of capabilities in a complete package for temperature control of high voltage and medium voltage oil cooled transformers.  The NT133-3 can monitor temperature, drive the cooling fans and calculate a thermal image of the 3 transformer windings using an exclusive algorithm.

The NT133-3 comes with 1 double RTD Pt100 input for a redundant control and 3 universal inputs for current transformers (CT).  Output relays are available for ALARM, TRIP, and FAN for driving the cooling system.  It also contains an output for PUMP control and a fault indication relay for signaling a sensor problem or a self diagnostic fault within the controller.  A digital Modbus 485 output allows for remote control.

On request, a protective coating can be applied to the electronics board for tropical climates.


  • Temperature monitoring from 0°C to 200°C (32° – 392°F)
  • 24-240VAC -DC input power
  • VDC with reversible polarities
  • Rated for use in ambient temperatures from -40° to +70°C (-40° to 158°F)
  • 2 inputs RTD Pt100 3 wires
  • 3 universal inputs (CT1, CT2, CT3 from 0.8 to 5.2A)
  • All potential free output relays rated for up to 5A @ 250VAC
  • 1 output relay for ALARM – Oil and Winding
  • 1 output relay for TRIP – Oil and Winding
  • 1 output relay for FAN
  • 1 output relay for PUMP
  • 1 alarm relay for sensor or self diagnostic fault
  • Modbus RS485 output for remote control functions