Test circuit with HV generator for electrical appliances operated from single=phase or three=phase mains - has low Ohm sensor and associated current monitoring circuit for checking resistance of current path between ground conductor and housing.

摘要

The test circuit includes a high voltage generator (21) which can be connected to the conductor contact. The test circuit (1) has a plug coupling (11) for the reception of the mains plug (5,6). The protective conductor contact (5,6) is connectible with the generator across a switching element (18) with earth potential (19). The circuit has at least two coupling connections for the mains voltage and an isolating contactor (16,17) before these. A sensing unit (14) is provided for applying at the housing surface (9,10) connected with the protective conductor contact (5,6). A current passage monitoring circuit (control circuit 12) is assigned to the sensing unit (14). It monitors the current between the protective conducting contact (5,6) and the housing surface (9,10) regarding low resistance. It delivers an activation signal, for the switching through of the mains voltage across the isolating contactor (16,17), so that an operational measuring circuit (26) delivers an activating signal for switching on the high voltage generator (21). USE/ADVANTAGE - Esp. also for appliances with switching on or switching off relays. Quick test which is simple for operator and gives unambiguous results.