Abstract: A network protector includes a coil drive circuit for the trip actuator which operates as a current limiter to protect a trip coil with limited impedance at the upper limit of network voltage while assuring operation at network voltages of less than 10% rated voltage. A comparator provides gate drive current to a FET connected in series with the trip coil as long as coil current is below a reference voltage proportional to a specified maximum value of coil current. When the specified value of coil current is reached, the FET is latched off until the network protector is tripped open again.

Abstract: Conductive polymer current-limiting fuses. when connected in series with conventional mechanical circuit breakers, exhibit extremely low let-through values. Particularly, conductive polymer current-limiting fuses based on conductive elastomeric material are disclosed which exhibit extremely low let-through values, namely less than 5,000 A2s with a switch current of 1.79 kAp, preferably less than 2,500 A2s, most preferably no more than 2,250 A2s.