High power hybrid contactor for electrical test application

It´s been a practice to use a back up contactor in addition to master contactor to evaluate the electrical life of the test contactor for AC-3 utilisation category. It is expected that the life of the test contactor is in few millions, which the back - up contactor may not be able to support as during each make - break operation there is heavy erosion of contact material due to arcing. It demands frequent maintenance or even replacement of the back - up contactor to complete the AC-3 electrical life test. The paper reveals about the development of a test set up to perform AC-3 electrical life test upon the test contactor using a high power hybrid back up contactor which will provide millions of arc less switching. At the outset it explains about the control & power circuit and then discuss in detail about the prototype development and performance evaluation of the test set up done upon the test contactor. The test results reveal about arc less breaking operation of the hybrid contactor at 415V, 2.1kA, 50Hz, 0.35 power factors with no pit marks, crater formation and contact erosion. It is expected to complete millions of operations.