Combined device of electric protection at low voltage against transient and extended over-voltage with automatic reconnection

摘要

Combined protection device which protects against both transient and extended over-voltages forming a single assembly and which is associated in its operation with a remote control unit connected in turn with a cut-out unit. The device has a protection circuit against transient over-voltages in association with a protection circuit against extended over-voltages which in turn is formed by a power supply unit which produces a doubly stabilized voltage (+Vcc) with low thermal drift, a control unit which compares the supply voltage with a reference obtained from the voltage (+Vcc) so that when it is surpassed for a predetermined time some signals are produced which when delivered to the control unit produce the disconnection of the cut-out unit, whilst when the supply voltage returns to its normal values the reconnection takes place. Furthermore it also has a power unit which adapts the pulses to some switching means which assure the actuation of the remote control unit.