| 摘要 |
<p>PURPOSE:To prevent overcurrent flow through an armature circuit upon recovery from separated wire condition, by producing a field strengthening signal when at least one of differentiated stringing voltage separated wire detection signal or differential armature current separated wire detection signal is detected. CONSTITUTION:In a stringing voltage separated wire signal generator 18, a comparator 21 produces a differentiated stringing voltage separated wire detection signal PID1 if a differentiated stringing voltage DEC is higher than a differentiated stringing voltage separated wire detection set value DECR. In an armature current separated wire signal generator 23, a comparator 26 produces a differential armature current wire separation detection signal PID2 if a differential armature current DELTAIA is higher than a differential armature current wire separation detection set value DIR. When at least one of the signals PID1 and PID2 is provided, an OR gate 22 provides a wire separation detection signal PID to a pulse generator 27 and strengthens the field.</p> |
