公开(公告)号：EP0336943A4

公开(公告)日：1991-07-17

申请号：EP88908844

申请日：1988-09-16

申请人： SQUARE D COMPANY

发明人： REED, RYAN, T. ,  CURRAN, EARL, J., JR.

IPC分类号： H02H3/10 ,  H02H1/04 ,  H02H3/13 ,  H02H3/20 ,  H02H3/253 ,  H02H3/34 ,  H02H3/12

CPC分类号： H02H3/253 ,  H02H1/04

摘要： In phase loss detection circuits a false indication can occur doing the starting, stopping and severe load transitions of a three-phase motor. The present phase loss detection circuit solves this problem by using a circuit (33) to detect the lost of a phase, a comparator (25), a changing capacitor (C5), a peak detection (21) and an overload voltage integrator (38), all of which provide a positive indication of either a phase loss or overload condition. The present phase loss circuit including transient protection which may be used with three-phase motors in a three-phase electrical system.