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Transformer Advantage 3 CT


Oil & Winding Temperature Monitor for Oil-Filled Transformers
CT model replaces oil and up to three winding temperature gauges.

The Transformer Advantage is a precision oil & winding temperature monitor for liquid immersed power and distribution transformers. It is rugged, fully electronic and field configurable. With Transformer Advantage, users can extend transformer life, u tilize maximum capacity and reduce maintenance costs.

Five models in the Advantage line offer a range of functions and configurations. All use an accurate and stable platinum temperature sensor (RTD) to precisely measure critical liquid temperatures. Probe options fit most popular thermowells, or magnetically mount on units without wells.  Setpoint relays can activate alarms or multiple stages of cooling at different temperatures. A sequencing function equalizes run time between cooling stages. The fan timer can exercise fans at a preset time each day.

Advantage 3 CT
The Advantage CT model directly measures transformer oil temperature and transformer load currents. Winding temperature is calculated from the measured current, liquid temperature and key transformer parameters. This calculation uses a proprietary algorithm based on IEEE C57.91. The sophisticated algorithm also provides different thermal profiles for natural, forced or directed oil cooling. An existing current transformer can be wired directly to the Advantage CT, or the clamp-on option can be ordered to avoid CT loop rewiring. The 3 winding option displays separate temperatures, based on each winding’s characteristics. Up to 4 channels of analog output track oil temperature, winding temperatures and/or load current. Auxiliary analog/digital inputs allow the Advantage CT to monitor cooling circuits and adjust the winding temperature calculation based on the cooling equipment actually operating. Other transformer devices can also be monitored for transmission to a SCADA system or to activate alarms.

  • One  RTD input.
  • One to three winding current inputs.
  • Winding temperature calculated per IEEE guide.
  • Up to 12 relay outputs for cooling and alarms.
  • Analog retransmits.
  • Cooling fan readback.
  • Auxiliary inputs.
  • Loss of life (insulation aging).
  • Ethernet & Fiber communication options.
  • DNP3 & Modbus protocols.

Part numbers for Advantage 3 CT models begin with G4N or G4P; older models with G4E, G4L, or G4R.

Transformer-Advantage 3-Datasheet             Advantage 3 Simplified Selector

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Setpoint Relays
First RTD Probe
TOP OIL or FLUID (4 wire)
Second RTD Probe
CT Input

Enter 2 digit code for full scale % of 10 amps.
Example 50=5 amps, 10=1 amp.
Enter 00 for 10 amps.
Enter SA for >10 amps (specify value on order).
Enter SP for <1 amp or special (specify on order).

Note: Letter codes U & T are not available with Ethernet or Fiber communications
SCADA Outputs
Walk-up USB port & DNP3/Modbus protocols included on all models
Thermowell Probe Adapters
Threaded adapter & tip sleeve for each thermowell probe ordered.
Input Options
Miscellaneous Options

3 digits required in part number. If no options needed, select both X & XX.
If more than 3 needed, select SXX and list on order.
Note: Ethernet or Fiber communications are not available for Power codes U & T. When Miscellaneous Option T, E or G is installed, active port for remote communication is selected during setup. Local USB port is always active.

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