Varistors are clamping devices used to protect power systems from voltage surges generated either by lightning discharge or switching in power circuits. Varistor tests for clamping voltage and energy absorption require use of the 8/20 µs, 10/350 µs and 10/1000 µs current impulses. Often referred to as SPDs or MOVs, varistors are required to have power dissipation tested in event that the device is activated. Under these conditions there is a high follow current from the power supply conducted through the varistor.
Impulse generators cover the range 20 A for testing SPD devices up to 100 kA for testing high voltage varistors. Testing directly with AC power is possible with Coupling Decoupling Networks up to 1,200 Vac. All high voltage outputs can be covered with TC-ST test cabinet for personnel safety.
