System for protecting a dc power distribution bus during hot servicing

Claim 2

In a power distribution system including load circuits each coupled to an energized bus by a power connector element and return connector element, a system for reducing the effects of connecting a load to the energized bus, said system comprising: a current limit device included in the load circuit for limiting the flow of current in the load circuit; a low impedance path included in the load circuit that bypasses said current limit device when activated; wherein the current in the load circuit is non zero and flows through one of said current limit device and said low impedance path; a switch, having a control input for receiving a control voltage, for activating said low impedance path to bypass said current limit device when the magnitude of said control voltage is in a predetermined range; means, coupled to said current limit device, for generating said control voltage in said predetermined range when the current flow thorough said current limit device drops below a predetermined level.

Claim 3

The system of claim 1 further including a system for reducing the effects of disconnecting a load circuit from an energized bus and further comprising: means for deactivating said low impedance path prior to disconnecting load circuit from the energized bus to reinsert said current limit device into the load circuit.

Claim 4

The system of claim 1 further including an overload protection circuit comprising: an overload sensing resistor, having first and second terminals, connected in series with said current limit device; means, having inputs connected to the terminals of said overload sensing resistor, for deactivating said low impedance path when the voltage drop across said overload sensing resistor exceeds a predetermined limit.

Claim 5

The system of claim 1 further comprising: a diode for isolating said power connector element from the load circuit to prevent reverse current flow in the event of a power supply failure.

Claim 6

In a power distribution system including load circuits each coupled to an energized bus by a power connector element and return connector element, a system for reducing the effects of connecting a load to the energized bus, said system comprising: a current limit device included in the load circuit for limiting the flow of current in the load circuit; a low impedance path included in the load circuit that bypasses said current limit device when activated; a switch, having a control input for receiving a control voltage, for activating said low impedance path when the magnitude of said control voltage is in a predetermined range; means, coupled to said current limit device, for generating said control voltage in said predetermined range when the current flow through said current limit device drops below a predetermined level, wherein: said switch is a transistor having a control input responsive to the level of current flow through said current limit device, an activation port coupled to said low impedance path, and a third port, where current can flow through said transistor to activate said low impedance path when said third port is coupled to the energized bus; the power and return connectors are pin/receptacle pairs of a predetermined length; the third port of said switch transistor is coupled to the bus by a selected pin/receptacle pair of shorter length than said predetermined length so that said selected pin/receptacle pair disengages prior to the disconnection of said load to deactivate said low impedance path.

Claim 7

In a power distribution system including load circuits each coupled to an energized bus by a power connector element and return connector element, a system for reducing the effects of connecting a load to the energized bus, said system comprising: a current limit device included in the load circuit for limiting the flow of current in the load circuit; a low impedance path included in the load circuit that bypasses said current limit device when activated; a switch, having a control input for receiving a control voltage, for activating said low impedance path when the magnitude of said control voltage is in a predetermined range; means, coupled to said current limit device, for generating said control voltage in said predetermined range when the current flow through said current limit device drops below a predetermined level, wherein: said switch is a transistor having a control input responsive to the level of current flow through said current limit device, an activation port coupled to said low impedance path, and a third port, where current can flow through said transistor to activate said low impedance path when said third port is coupled to the energized bus; the power and return connectors are pin/receptacle pairs of a predetermined length; the third port of said switch transistor is coupled to the bus by a selected pin/receptacle pair of shorter length than said predetermined length so that said selected pin/receptacle pair disengages prior to the disconnection of said load to deactivate said low impedance path.