Toroidal Current Transformer, Motor/ Circuit Protection

Application: Incorporated into 380VAC or 660VAC electric power current monitoring applications where a high over load rating in harsh operating environments are critical performance requirements. Application examples included AC motor protection, air compressor/ HVAC (heating, ventilation and air conditioning systems) protection, or any application which requires the monitoring and protection of industrial equipment against current surges.


  • Incorporates high performance electromagnetic cores.
  • Characterized by high sensitivity, accuracy, linearity, minimum phase shift.
  • High over load rating multiples.
  • Single phase, three phase, or three phase plus neutral monitoring configurations.


  • Input Frequency: 50 to 400HZ
  • Accuracy Class: Compliant with IEC60044-1 Part 1, Current Transformers Class 0.5, 1.0
  • Operating Voltage: 600 VAC
  • Isolation Voltage: 2,500Vrms for 1 minute
  • Dielectric Resistance: 1,000 M Ohms @ 500VDC
  • Surge Withstand Voltage: 5,000V
  • Rated Load Resistance: 100K Ohms
  • Operating temperature: -40ºC to +85ºC
  • Construction:
    • Case: PBT or ABS Resin, UL flame retardant rating 94V-0
    • Interior Insulation: Epoxy encapsulated
  • RoHS Compliant

Standard Sizes – Single Phase:

  • CTT0150 standard models – 15.0mm (0.59in) window, UL Certified
  • CTT0200 standard models – 20.0mm (0.79in) window
  • CTT0250 standard models – 25.0mm (0.98in) window
  • CTT0350 standard models – 35.0mm (1.38in) window, UL Certified
  • CTT0450 standard models – 45.0mm (1.77in) window
  • CTT0550 standard models – 55.0mm (2.17in) window, UL Certified
  • CTT0720 standard models – 72.0mm (2.83in) window, UL Certified

Standard Sizes – Three Phase:

  • TA7161 standard models – 10.0mm (0.39in) window
  • TA7261 standard models – 20.0mm (0.79in) window
  • TA7361 standard models – 20.0mm (0.79in) window
  • TA7761 standard models – 30.0mm (1.18in) window

Standard Sizes – Three Phase – DIN Rail Mounted:

  • TA7661 standard models – 20.0mm (0.79in) window

Many of our products can be designed and manufactured to meet the specific application requirements. For a no obligation technical evaluation, contact us with your specific performance requirements.