Electromechanical relays

摘要

PCT No. PCT/GB94/01438 Sec. 371 Date Jun. 5, 1995 Sec. 102(e) Date Jun. 5, 1995 PCT Filed Jul. 4, 1994 PCT Pub. No. WO95/02254 PCT Pub. Date Jan. 19, 1995A device for preventing welding of the switch contacts of a heavy duty electromechanical relay comprises means (15, 16 and 17) adapted in use for monitoring the voltage supply to the relay coil (2) and detecting low voltage excursions therein. A counter (14) counts the number of low voltage excursions in the voltage supply to the relay coil (2) and an electronic switch (12) disconnects the voltage supply to the relay (2) if the number of low voltage excursions counted exceeds a predetermined number.