US 5,661,623 A · Ground fault circuit interrupter plug

Abstract

A ground fault circuit interrupter (GFCI) line cord plug utilizes an electronically latched relay, rather than a circuit breaker or other type of mechanical latching device, to interrupt the AC load power when a ground fault condition occurs. In order to reduce the size of the relay and minimize the cost and complexity of the GFCI plug, the fixed and movable relay contact structures are mounted directly to the circuit board which carries the remaining components of the GFCI circuit. In a preferred embodiment, the fixed relay contact structures are integral with the plug blades of the GFCI plug. The movable relay contact structures preferably comprise deflectable spring arms which are preloaded when the relay contacts are in the open position in order to control the contact gap, and which are deflected past the point of contact closure when the relay contacts are in the closed position in order to increase the closing force. The principal electrical components of the GFCI plug, including the relay contacts, relay coil and sensing transformer, are mounted on the circuit board in a generally tandem or in-line arrangement in order to minimize the dimensions of the plug.

Claims23

Dependent claims

A ground fault circuit interrupter plug comprising:

a housing having a pair of plug blades for connection to an AC receptacle and a pair of output terminals for connection to an AC load;
a circuit board within said housing;
and
electrical circuitry carried by said circuit board for providing ground fault protection to an AC load connected to said output terminals, said electrical circuitry including:
a relay comprising a relay coil and a pair of relay contact sets operated by said relay coil for selectively connecting and disconnecting said plug blades and said output terminals, each of said relay contact sets comprising a fixed contact structure mounted to said circuit board and a movable contact structure mounted to said circuit board;
and
an electronic circuit coupled to said relay coil for maintaining said relay contact sets in a closed position to connect said plug blades to said output terminals in the absence of a ground fault condition, and for causing said relay contact sets to move to an open position to disconnect said plug blades from said output terminals in response to a ground fault condition.

4 more elements

Dependencies are inferred from the claim text.

Ground fault circuit interrupter plug

Life of this patent

Ground fault circuit interrupter plug

Life of this patent

Abstract

Claims23