Leakage current detection interrupter with fire protection means

• US 7,889,464 B2
• Filed: 10/26/2006
• Issued: 02/15/2011
• Est. Priority Date: 12/23/2005
• Status: Active Grant

• Current Assignee: Heng Chen
• Original Assignee: General Protecht Group Incorporated
• Inventors: Li, Xiaoyong, Wang, Fu, Chen, Wusheng, Dai, Yong, Song, Huaiyin
• Primary Examiner(s): Fureman; Jared J
• Assistant Examiner(s): Ieva; Nicholas
• Application Number:
  US11/588,044
• Publication Number:
  US 20070146946A1
• Time in Patent Office: 1,573 Days
• Field of Search: 361/42
• US Class Current: 361/42
• CPC Class Codes: H01H 73/44 reset by push-button, pull-knob or slide
• CPC Class Codes: H01H 83/04 with testing means for indicating the ability of the switch or relay to function properly
• CPC Class Codes: H01H 83/14 operated by imbalance of two or more currents or voltages, e.g. for differential protection
• CPC Class Codes: H02H 3/33 using summation current transformers H02H3/347 takes precedence
• CPC Class Codes: H02H 5/10 responsive to mechanical injury, e.g. rupture of line, breakage of earth connection

Abstract

A leakage current detection interrupter with fire protection means, comprising: (i) a leakage current protection circuit, (ii) an electrical cord with metallic fire shields, and (iii) a fire protection circuit, wherein, in operation, the leakage current protection circuit and the fire protection circuit detect a fault condition including a leakage current, a ground fault and a fire hazard, and disconnect the source of electricity from the at least one user accessible load when leakage current, ground fault or fire hazard is detected. The electrical cord with metallic fire shields, the fire protection circuit, and the indicator circuit can be combined with any ground fault circuit interrupter, arc fault circuit interrupter, immerse detection circuit interrupter, appliance leakage current interrupter and electronic leakage current interrupter.

Claims

1. A leakage current detection interrupter with fire protection means, comprising:

(i) a line phase terminal, a line neutral terminal, a line ground terminal, a fire protection terminal, a first output, a line second output and a third output, wherein the line phase terminal, the line neutral terminal, and the line ground terminal are connectable to a source of electricity, and the first output, the second output and the third output are connectable to at least one user accessible load;

(ii) a leakage current protection circuit having;

a first switch having a first terminal and a second terminal respectfully connected to the line phase terminal and the first output, an opening position in which the line phase terminal is disconnected to the first output, and a closing position in which the line phase terminal is connected to the first output;

a second switch having a first terminal and a second terminal respectfully connected to the line neutral terminal and the second output, an opening position in which the line neutral terminal is disconnected to the second output, and a closing position in which the line neutral terminal is connected to the second output;

an trip coil having a first terminal connected to the first terminal of the first switch and a second terminal coupled to the first terminal of the second switch, configured such that when being activated, the trip coil causes the first switch and the second switch to be in the opening position simultaneously;

an inductive coil having a first terminal and a second terminal, coupled to the first output and the second output for sensing a current difference in the line from the line phase terminal to the first output and the line from the line neutral terminal to the second output; and

a leakage current detection circuit having a first input terminal and a second input terminal respectively connected to the first terminal and the second terminal of the inductive coil, a first output terminal connected to the second terminal of the trip coil and a second output terminal connected to the first terminal of the second switch, configured such that when a fault conduction is detected through the inductive coil, the leakage current detection circuit responsively outputs a current to activate the trip coil, thereby causing the first switch and the second switch to be in the opening position simultaneously, wherein the fault conduction is corresponding to the current difference sensed by the inductive coil larger than a predetermined value;

(iii) an electrical cord having;

a phase wire, a neutral wire, a ground wire, an insulation film covering the phase wire, the neutral wire and the ground wire, and a metallic shield covering the insulation film, wherein the phase wire, the neutral wire and the ground wire are respectively connected between the first output, the second output and the third output, and the at least one user accessible load, and the metallic shield is connected to the fire protection terminal;

(iv) a fire protection circuit having;

a pair of rectifying diodes, each rectifying diode having an anode and a cathode, wherein the anodes of the pair of rectifying diodes are respectively connected to the line phase terminal and the line neutral terminal; and

a resistor having a first terminal connected to the cathodes of the pair of rectifying diodes and a second terminal connected to the fire protection terminal,

wherein when a fire hazard occurs, it causes the insulation film of the electrical cord to melt down so that the metallic shield is contact with one of the core the phase wire, the neutral wire and the ground wire of the electrical cord, which in turn, detours a current from the fire protection terminal through the fire protection circuit, thereby causing the current difference in the line from the line phase terminal to the first output and the line from the line neutral terminal to the second output, which results in the first switch and the second switch in the opening positions; and

(v) an indicator circuit having;

a diode having an anode connected to the fire protection terminal, and a cathode;

a resistor having a first terminal connected to the cathode of the diode, and a second terminal; and

a light emitting diode (LED) having an anode connected to a second terminal of the resistor and a cathode connected to the second output,

wherein the LED lights up in a normal working condition in which the first switch and the second switch are in the closing position, and the LED is not lit in a fault condition in which the first switch and the second switch are in the opening position.

2. The leakage current detection interrupter with fire protection means of claim 1, wherein the leakage current protection circuit comprises:

(i) a movable assembly housing having a first side surface and an opposite, second side surface, and a body defined therebetween, wherein the body defines two vertical slots on the first side surface and the second surface for a balance frame to slidably move up and down therein, wherein the balance frame comprises a first surface, an opposite, second surface, a first side surface, an opposite, second side surface, a top surface and an opposite, bottom surface, and a body portion defined therebetween, a first contact support protruding from the first side surface away from the body portion, a second contact support protruding from the second side surface away from the body portion, wherein the body portion defines an opening through the center of the top surface through center of the bottom surface of the body portion, and a slot in proximity of the bottom surface through the first surface and the second surface of the body portion;

(ii) a first fixed contact holder having a first fixed contact, and a second fixed contact holder having a second fixed contact;

(iii) a first movable contact holder and a second movable contact holder, each having a fixed end attached to the movable assembly housing and a movable end, wherein the first movable contact holder has a first movable contact at the movable end and the second movable contact holder has a second movable contact at the movable end, and wherein the fixed end and the movable end of the first movable contact holder and the fixed end and movable end of the second movable contact holder are configured to create a resilience force separating the first movable contact from the second fixed contact and the second movable contact from the first fixed contact;

(iv) a movable assembly operatively associated with the moving assembly housing that moves between a first position in which the first movable contact holder and the second movable contact holder are pushed upwards against the resilience force by the contact supports on both sides of the balance frame such that the first movable contact makes contact with the second fixed contact and the second movable contact makes contact with the first fixed contact, and a second position in which the balance frame moves downward from the action of the resilience force and the first movable contact is separated from the second fixed contact and the second movable contact is separated from the first fixed contact each fixed contact makes contact with the respective movable contact and a second position in which the fixed contacts are separated from the movable contacts;

(v) a resetting component having a first end accessible to a user for resetting the leakage current detection interrupter and a second end with a tapered tip and a notch, which, when the movable assembly is in the first position, is engaged with the movable assembly;

(vi) a resetting component spring which releases the resetting component to disengage the movable assembly for moving from the first position to the second position; and

(vii) an electromagnetic tripping component, which, when energized, which is responsive to a fault condition, causes the movable assembly to be in the second position from the first position, thereby causing the resetting component to disengage the movable assembly.

3. The leakage current detection interrupter with fire protection means of claim 2, wherein the movable assembly comprises:

(i) a trip coil frame with an opening through the center of the trip coil frame and with the electromagnetic tripping component wound on the trip coil frame;

(ii) a magnetic core having a first end and an opposite, second end, with the first end positioned outside of the center opening of the trip coil frame and the second end positioned inside of the center opening of the trip coil frame, wherein the magnetic core stays in the first position when no fault condition is detected and moves to the second position when a fault condition is detected and the electromagnetic tripping component is energized;

(iii) a core spring to keep the magnetic core in the first position when no fault condition is detected and the electromagnetic tripping component is not energized;

(iv) a resetting component locker having a upper portion and a lower portion, wherein the lower portion is substantially perpendicular to the upper portion, the upper portion is slidably attached to the first end of the magnetic core outside of the center opening of the trip coil frame; and

(v) the balance frame wherein the lower portion of the resetting component locker is slidably insertable in the slot in proximity of the bottom surface, and wherein the balance frame is able to slide up and down along the vertical slots of the movable assembly housing,

wherein in operation, when the resetting component is pressed, the notch of the resetting component pushes the resetting component locker horizontally so the resetting component locker is engaged with the notch of the resetting component and locks the resetting component, and the resilience of the resetting component spring pulls the balance frame and the resetting component locker upward such that the first movable contact holder and the second movable contact holder are pushed upward by the contact supports on both sides of the balance frame and causes the movable assembly to be in the first position where the resetting component is slidably inserted in the slot of the balance frame, and when a fault condition is detected by the leakage current protection circuit, a current is directed to the electromagnetic tripping component causing an electromagnetic force to pull the magnetic core towards the trip coil frame, along with the resetting component locker, such that the resetting component locker is released from the engagement with the resetting component, and the balance frame together with the resetting component locker moves downward at the action of the resilience force of the first movable contact holder and the second movable contact holder to set the movable assembly in the second position.

4. The leakage current detection interrupter with fire protection means of claim 3, wherein the electromagnetic tripping component is covered by a metal shield on four sides for protecting the electromagnetic tripping component from failing during a fire condition.

5. The leakage current detection interrupter with fire protection means of claim 1, wherein the electrical cord comprises at least one electrical plug.

6. The leakage current detection interrupter with fire protection means of claim 1, wherein the electrical cord comprises at least one electrical socket.

7. The leakage current detection interrupter with fire protection means of claim 1, wherein the leakage current detection circuit further comprises:

(i) a first capacitor connected in parallel to the first terminal and the second terminal of the inductive coil;

(ii) an integrated circuit having a first terminal, a second terminal, a third terminal connected to the second input, a fourth terminal connected to the second output terminal, a fifth terminal, a sixth terminal, a seventh terminal, and an eighth terminal;

(iii) a first resistor having a first terminal connected to the first terminal of the inductive coil, and a second terminal connected to the second terminal of the integrated circuit;

(iv) a second resistor having a first terminal connected to the first terminal of the integrated circuit and a second terminal connected to the second terminal of the integrated circuit;

(v) a second capacitor having a first terminal connected to the sixth terminal of the integrated circuit, and a second terminal connected to the second output terminal;

(vi) a third capacitor having a first terminal connected to the seventh terminal of the integrated circuit, and a second terminal connected to the second output terminal;

(vii) a fourth capacitor having a first terminal connected to the eighth terminal of the integrated circuit, and a second terminal connected to the second output terminal;

(viii) a silicon controlled rectifier having a cathode connected to the second output terminal, a gate connected to the seventh terminal of the integrated circuit, and an anode connected to the first output terminal;

(ix) a fifth resistor having a first terminal connected to the anode of the silicon controlled rectifier, and a second terminal; and

(x) a diode having an anode connected to the second terminal of the fifth resistor, and a cathode connected to the fifth terminal of the integrated circuit.

8. A leakage current detection interrupter with fire protection means, comprising:

(i) a line phase terminal, a line neutral terminal, a line ground terminal, a fire protection terminal, a first output, a line second output and a third output, wherein the line phase terminal, the line neutral terminal, and the line ground terminal are connectable to a source of electricity, and the first output, the second output and the third output are connectable to at least one user accessible load;

(ii) a leakage current protection circuit having;

a first switch having a first terminal and a second terminal respectfully connected to the line phase terminal and the first output, an opening position in which the line phase terminal is disconnected to the first output, and a closing position in which the line phase terminal is connected to the first output;

a second switch having a first terminal and a second terminal respectfully connected to the line neutral terminal and the second output, an opening position in which the line neutral terminal is disconnected to the second output, and a closing position in which the line neutral terminal is connected to the second output;

an trip coil having a first terminal connected to the first terminal of the first switch and a second terminal coupled to the first terminal of the second switch, configured such that when being activated, the trip coil causes the first switch and the second switch to be in the opening position simultaneously;

an inductive coil having a first terminal and a second terminal, coupled to the first output and the second output for sensing a current difference in the line from the line phase terminal to the first output and the line from the line neutral terminal to the second output; and

a leakage current detection circuit having a first input terminal and a second input terminal respectively connected to the first terminal and the second terminal of the inductive coil, a first output terminal connected to the first terminal of the second switch and a second output terminal connected to the second terminal of the trip coil, configured such that when a fault conduction is detected through the inductive coil, the leakage current detection circuit responsively outputs a current to activate the trip coil, thereby causing the first switch and the second switch to be in the opening position simultaneously, wherein the fault conduction is corresponding to the current difference sensed by the inductive coil larger than a predetermined value;

(iii) an electrical cord having a phase wire, a neutral wire, a ground wire, an insulation film covering the phase wire, the neutral wire and the ground wire, and a metallic shield covering the insulation film, wherein the phase wire, the neutral wire and the ground wire are respectively connected between the first output, the second output and the third output, and the at least one user accessible load, and the metallic shield is connected to the fire protection terminal;

(iv) a fire protection circuit having;

a pair of rectifying diodes respectively coupled to the line phase terminal and the line neutral terminal; and

a resistor coupled between the pair of rectifying diodes and the fire protection terminal,

wherein when a fire hazard occurs, it causes the insulation film of the electrical cord to melt down so that the metallic shield is contact with one of the core the phase wire, the neutral wire and the ground wire of the electrical cord, which in turn, detours a current from the fire protection terminal through the fire protection circuit, thereby causing the current difference in the line from the line phase terminal to the first output and the line from the line neutral terminal to the second output, which results in the first switch and the second switch in the opening positions; and

(v) an indicator circuit having;

a diode having an anode connected to the fire protection terminal, and a cathode;

a resistor having a first terminal connected to the cathode of the diode, and a second terminal; and

a light emitting diode (LED) having an anode connected to a second terminal of the resistor and a cathode connected to the second output,

wherein the LED lights up in a normal working condition in which the first switch and the second switch are in the closing position, and the LED is not lit in a fault condition in which the first switch and the second switch are in the opening position.

9. The leakage current detection interrupter with fire protection means of claim 8, wherein the anodes of the pair of rectifying diodes are respectively connected to the line phase terminal and the line neutral terminal;

and the resistor having a first terminal connected to the cathodes of the pair of rectifying diodes and a second terminal connected to the fire protection terminal.

10. The leakage current detection interrupter with fire protection means of claim 8, wherein the cathodes of the pair of rectifying diodes are respectively connected to the line phase terminal and the line neutral terminal;

and the resistor having a first terminal connected to the anodes of the pair of rectifying diodes and a second terminal connected to the fire protection terminal.