T-Rex
Phase Angle Extender

T-Rex: Fully Automatic, Three Phase Voltage Extension to Turns Ratio Meter

The Raytech T-Rex three phase voltage extension is an optional system accessory for 3-Phase transformer ratio meter test sets designed by Raytech (i.e. TR-Mark III).

It was designed to give Engineers and Test Technicians the ability to test the phase relationships and actual voltage ratios of transformer windings while applying three phase voltage.

The system (in connection with a 3 phase Raytech Turns Ratiometer) precisely measures the ratio and angular relationship of transformer phases with voltage applied to all three phases simultaneously. This is a “real condition” measurement, which allows greater understanding of how the transformer will operate connected to a 3 phase system.

The T-Rex is contained within a separate yellow case and comes complete to connect to the Raytech TR-Spy, TR-Mark II or TR-Mark III three phase transformer ratiometer.

The T-Rex is especially useful for transformers with:

  • Phase relationships other than multiples of 30°
  • Zig Zag windings
  • Uncentered neutral points
  • Suspected broken, damaged, or missing core laminations


  • Optional System Accessory for TR-Mark III 250V
  • Controlled by the TR-Mark III 250V
  • Single Connection to the Transformer
  • Output is a Pure 3-Phase Sine Wave
  • Automatic Test Voltage Frequency Selection
  • Measures Phase Relationships other than multiples of 30°
  • Measures Phase Shifting Transformers as well as Power Rectifier Transformers
  • 5-Year Standard Warranty
  • Retired models: TR-Mark III and TR-Spy Mark II will communicate with the T-Rex