Auxiliary Current Transformers

General Details

Auxiliary Current Transformers

Auxiliary current transformers are designed for connection in the secondary circuit of a main current transformer to change the effective ratio on meters or relays.

Auxiliary current transformers are No window type, with many variations of current ratios available depending on model.

A Current Transformer (CT) is a type of transformer that is used to reduce or multiply an alternating current (AC). It produces a current in its secondary which is proportional to the current in its primary.

Current Transformers, along with voltage or potential transformers, are instrument transformers. Instrument transformers scale the large values of current to small, standardized values that are easy to handle for measuring instruments and protective relays. The Instrument transformers isolate measurement or protection circuits from the high voltage of the primary system. These units provide a secondary current that is accurately proportional to the current flowing in its primary, presenting a negligible load to the primary circuit.

These units are the current sensing units of the power system and are used at generating stations, electrical substations, and in industrial and commercial electric power distribution.

Advantages of Current Transformers are that the units can measure high current easily, high electrical isolation, simple construction, and easy maintenance and installation.

The Crompton Instruments product range represents one of the largest product offerings of power measurement, control, and protection instrumentation, for switchgear and generator set manufacturers, panel builders and OEMs.

Crompton Instruments products offer proven reliability across a diverse array of industries including power generation, process control, test and measurement, utility, marine, defence and energy management applications. To meet the challenges of ever decreasing lead times and industry developments, design and manufacturing processes are constantly reviewed and updated.


  • Higher accuracy
  • Higher burden capacity
  • Higher efficiency
  • Insulation Level of 600V, 10kv BIL Full Wave, 50-500 Hz
  • No Window Type
  • Ratios from 2.5 to 100:5 amps ac



  • CSA
  • UL


Model 190X

Model 190X

  • CSA
  • UL