Leakage current detection and interruption circuit powered by leakage current
View Patent ↗A circuit is disclosed for disconnecting a power source upon the detection of a leakage current from one of a first and a second wire connected to the power source. A sensing conductor is located adjacent to one of the first and second wires for sensing a leakage current from one of the first and second wires. A disconnect switch is interposed within the first and second wires connected to the power source. A disconnect switch control circuit is connected to the sensing conductor for opening the disconnect switch upon the presence of a leakage current from the sensing conductor. The disconnect switch control circuit operates solely from the leakage current from the sensing conductor.
1. A circuit for disconnecting a power source upon the detection of a leakage current from one of a first and a second wire connected to the power source, comprising:
a sensing conductor located adjacent to one of the first and second wires for sensing a leakage current from one of the first and second wires;
a disconnect switch interposed within the first and second wires connected to the power source;
said disconnect switch having a disconnect switch solenoid coil for opening said disconnect switch;
a threshold conduction device being conductive upon a threshold voltage applied to the threshold conduction device;
a connector connecting said disconnect switch solenoid coil in series with said threshold conduction device between one of the first and second wires and said sensing conductor; and
a threshold voltage generator comprising a capacitor connected in series with a diode between said sensing conductor and one of the first and second wires for charging said capacitor for generating said threshold voltage for said threshold conduction device upon a leakage current flow between said sensing conductor and one of the first and second wires and through said threshold voltage generator.
2. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said sensing conductor comprises a first and a second shield sensing conductor located about the first and second wires.
3. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said sensing conductor comprises a shield sensing conductor located about both of the first and second wires.
4. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said disconnect switch includes a normally open solenoid operated switch;
a mechanical latch mechanism for maintaining said disconnect switch in a closed condition and
said disconnect switch solenoid coil operating a plunger for disengaging said mechanical latch mechanism for opening said disconnect switch.
5. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said threshold conduction device includes a thyristor.
6. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said threshold conduction device includes a silicon, control rectifier (SCR).
7. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said threshold conduction device includes a silicon control rectifier (SCR) with a Zener diode connected to a gate of said silicon control rectifier (SCR).
8. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said threshold conduction device is a Diode For Alternating Current (DIAC).
9. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 1 , wherein said threshold conduction device is a Silicon Diode For Alternating Current (SIDAC).
10. A circuit for disconnecting a power source upon the detection of a leakage current from one of a first and a second wire connected to the power source, comprising:
a sensing conductor located adjacent to one of the first and second wires for sensing a leakage current from one of the first and second wires;
a disconnect switch interposed within the first and second wires connected to the power source;
said disconnect switch having a disconnect switch solenoid coil for opening said disconnect switch;
a divider circuit interconnected between the first and second wires for providing a divider node;
a threshold conduction device being conductive upon a threshold voltage applied to the threshold conduction device;
a connector connecting said disconnect switch solenoid coil in series with said threshold conduction device between said divider node and said sensing conductor; and
a capacitor connected between said divider node and said sensing conductor to provide said threshold voltage to said threshold conduction device upon a leakage current flow between said sensing conductor and one of the first and second wires.
11. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said divider circuit includes a diode divider circuit.
12. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 11 , wherein said divider circuit includes a resistive divider circuit.
13. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said divider circuit provides a voltage node.
14. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said capacitor is connected between said divider node and said sensing conductor and in parallel with said threshold conduction device.
15. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said threshold conduction device includes a silicon control rectifier (SCR).
16. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said threshold conduction device is a Diode For Alternating Current (DIAC).
17. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said threshold conduction device is a Silicon Diode For Alternating Current (SIDAC).
18. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said threshold conduction device comprises a thyristor connected in series with said disconnect switch solenoid coil between and said divider node and said sensing conductor; and
a breakdown voltage conduction device connected for actuating said thyristor upon said capacitor providing a breakdown voltage to said breakdown voltage conduction device.
19. A circuit for disconnecting a power source upon the detection of a leakage current as set forth in claim 10 , wherein said threshold conduction device comprises a thyristor connected in series with said disconnect switch solenoid coil and said divider node and said sensing conductor; and
a Zener diode connected to a gate of said thyristor for actuating said thyristor upon said capacitor providing a breakdown voltage to said Zener diode.
20. A circuit for disconnecting a power source upon the detection of a leakage current from one of a first and a second wire connected to the power source, comprising:
a sensing conductor located adjacent to one of the first and second wires for sensing a leakage current from one of the first and second wires;
a disconnect switch interposed within the first and second wires connected to the power source;
said disconnect switch having a disconnect switch solenoid coil for opening said disconnect switch;
a threshold conduction device being conductive upon a threshold voltage applied to the threshold conduction device;
a connector connecting said disconnect switch solenoid coil in series with said threshold conduction device between said divider node and said sensing conductor; and
a capacitor connected between said sensing conductor and one of the first and second wires for charging said capacitor with a leakage current flow between said sensing conductor and one of the first and second wires to provide said threshold voltage generator to said threshold conduction device.
21. A circuit for disconnecting a power source upon the detection of a leakage current from a wire connected to the power source, comprising:
a sensing conductor located adjacent to the wire for sensing a leakage current from the wire;
a disconnect switch interposed within the wire connected to the power source; and
a disconnect switch control circuit comprising a capacitor connected to said sensing conductor for opening said disconnect switch upon said capacitor accumulating a predetermined amount of the leakage current from said sensing conductor.