AC and DC Primary Current Injection Source are specially designed for testing and calibration of CTS , Bi-metal relays , etc. Each unit is designed as per the customers specification. These units are air cooled/ oil cooled depending upon capacity and duty cycle. Normally the Primary Injection Test Sets are designed for 15 minutes ON and 30 minutes OFF duty cycle and Loading Transformer for continuous duty used for temperature rise test of Bus duct , Bus bar and joins etc.