Electrical leakage measurement apparatus - applies high voltage across component and measures current using opto-electronic threshold detection circuit

摘要

The device measures electrical leakage, using an input isolating transformer (2) whose primary has a cut-out (4) in series and is supplied by the mains. A switchable supply unit (6) is fed from the secondary of the isolating transformer (2) and provides a high voltage of either polarity to the terminals of an electrical component (8) whose leakage is to be measured. One or more current measuring circuits (10, 14, 16) are connected in series with the component (8), as is a detection resistor (32). A detection circuit (36, 34, 42, 44) controlled by the voltage across the detection resistor (32), triggers the cut-out (4) when this voltage exceeds a variable threshold. The detection circuit includes a light source (34) and a photoelectric detector (42).