Contactor, Relay, Starter Test Bench


  • Pick up/ Drop off Voltage/ Time measurement -
    In this test, Coil voltage of the contactor is increased at the digitally fixed settable rate and the point voltage is obtained at which Contactor has picked up. and similarly Coil voltage is reduced to find the out the point voltage at which Contactor has dropped off. In this way, Pick up voltage test and Drop off voltage test of Contactor is carried out.
    With the help of high speed analog cards, We plot Voltage, Current and Continuity graphs in order to find out the Pick up time and Drop off time of the contactor with instantaneous voltage applied and removed.

  • Coil current/ VA rating measurement -
    Every contactor coil has some resistance and inductance and due to manufacturing process defects, quality of the Coil gets hampered and eventually performance of the contactor too. Hence, Coil current/ VA rating measurement test is conducted. In this test, 85%, 100% and 110% rated coil voltage is applied and corrosponding current consumption and power factor is measured. This test ensures that coil quality being used in the production is optimum and controlled.

  • Continuity/ Flashing test -
    Continuity test is basically conducted to ensure proper contact between moving and fixed contacts. Continuity/ Flashing test is conducted by doing contactor On & Off for say 50 times and continuity making and breaking is checked.

  • HV/ Dielectric Test -
    Every contactor should have sufficient gap between their moving contact and fixed contact, when in open state, to ensure proper isolation. To ensure this, HV (High voltage)/ Dielectric test is conducted on Contactor. In this, High voltage in the range of 2.5KV or 3KV or sometimes more depending on the contactor capacity, is applied accross the open poles of the contactor and the leakage current is measured in the range of 0.1mA to 50mA. This leakage current value should be minimum or below specified limits. This is product deteriorating test, hence usually conducted at the end of all tests.

  • Contact Gap/ Over Travel/ Total Travel measurement - 
    In Contactor, Moving contacts are assembled on to the Fixed contacts. Due to spring, moving contacts are maintained at some height and when Contactor is made On, still there is some over travel capacity to ensure the proper contact. Hence, CG,OT,TT test (Contact Gap, Over Travel, Total Travel) is conducted.

  • Contact resistance/ mV drop test of the contacts -
    Moving Contacts/ Fixed contacts should make contact firmly and should not offer any additional contact resistance. To ensure this, Contact resistance test/ mV drop test is conducted. This test ensures that Contacts are not offering any subsequent contact resistance and hence do not heat up during operation.

  • Bridge Spring Force measurement -
    Every contactor has a spring which holds the bridge up. This spring should have enough force to push and to keep the bridge up. To ensure this, Bridge spring force is measured using load cell.

  • Endurance Test -
    This test is of 2 types. Mechanical and Electrical endurance. It pushes and tests the contactor to its limits. In Endurance test, Contactors are made On/ Off for 1 to 50 million times. and during each operation, all the necessary parameters like coil current, coil power factor, Pick up time, Drop off time etc are measured and recorded in Computer database. In this test, Bridge spring force measurement and Contact resistance measurement is performed after every set number of cycles and data is generated.

  • Thermal/ Temperature rise test -
    In this test, Current is flowed through the relay and time taken by relay to Trip is measured. This is consolidated test for overall relay functionning and to ensure that combined error is below the specified limit.

  • Magnetic/ Short time withstand test -
    High current is passed for very small amount of time, say few mS, through the relay and checks whether it withstands and trips within the specified time limit.

  • Continuity Test -
    In this test, Relay is made On/ Off by pressing its buttons with actuators and continuity is monitored. This test usually done for say 10 times in various modes of relay. It mainly detects internal mechanism faults by pressing start, stop, trip buttons various times.