Poly Carbonate Current Transformers

  • Poly carbonate is durable material
  • High Impact resistance
  • Low scratch resistance
  • Usable in a wider temperature range
  • Compact in size compared to resin cast CT’s
  • Requires less cycle time compared to resin hence faster delivery.

Relay Operated Current Transformers

These are used in conjunction with contactors and motor control equipment. They provide accurate reliable against overload & single phasing.

Air Circuit breakers Current Transformers

Air Circuit Breakers are used right upto 6000A. For thermal & thermo magnetic protection CT is integral part. CTs are available in various insulation forms such as castings, thermoplastic & tape insulated.


  • Used for earth fault protection in grounded three phase systems
  • All the three phases are made to pass through the CT inner window

Summation CT

  • Consist of two or more primary windings which are connected to the feeders to be assumed.
  • A single secondary winding, which feeds a current proportional to the summed primary current.

Class PX CTs

  • In balance systems of protection, CT’s with a high degree of similarity in their characteristics is required. These requirements are met by class PS (PX) CT’s.
  • Their performance is defined in terms of a knee-point voltage (vk). the magnetizing current (imag) at the knee point voltage or 1/2, 1/4 the knee-point voltage, and the resistance of the CT secondary winding corrected to 75~c (Rct)


  • In an autotransformer, portions of the same winding act as both the primary & secondary sides of the transformer.
  • They are often used to step up or step down voltages in a smaller range. (eg. 110-115-120v)