Isolating protection circuit preventing electric shock - measures voltage between two electrodes on workers skin and triggers cut=out when limit is exceeded

摘要

The protection circuit measures the voltage between two electrodes on a worker's skin, in order to detect any large currents flowing through his body to ground from the equipment be is working on. If such an earth current is detected a cut-out is operated to protect the worker. A generator supplies the electrodes with pulses in order to measure the resistance between them. A voltage detector in the form of an Exclusive OR-gate operates the protective cut-out and/or a signalling device, when this voltage exceeds a given limit. The detector is linked from the worker to the cut-out by wires, audio signals or radio waves.