Ground fault circuit interrupter

• US 7,692,904 B2
• Filed: 09/18/2007
• Issued: 04/06/2010
• Est. Priority Date: 03/12/2007
• Status: Expired due to Fees

• Current Assignee: Hisetec Electronic Company Limited
• Original Assignee: Hisetec Electronic Company Limited
• Inventors: Yin, Yi, Dong, Xiaobing, Li, Xuguang
• Primary Examiner(s): Nguyen; Danny
• Application Number:
  US11/901,759
• Publication Number:
  US 20080225448A1
• Time in Patent Office: 931 Days
• Field of Search: 361 42- 50, 361 71- 74
• US Class Current: 361/45
• CPC Class Codes: H02H 11/002 in case of inverted polarity or connection; with switching for obtaining correct connection

Abstract

A method of preventing an overload current from a power supply to a load through a ground fault circuit interrupter includes the steps of: obtaining an interrupted fault current from a hot wire to a ground wire via a first zero-phase current inductor and a fault current from a neutral wire to the ground wire via a second zero-phase current inductor; amplifying a signal of the fault current by an Op-Amp; and determining the fault current by a programmable control module, wherein when the fault current is larger than a preset threshold, the programmable control module sends a control signal to a control switch such that the control switch electrifies a second coil of a trip breaker to drive an armature at an unlocked position, so as to separate a movable terminal with a fixed terminal for electrically disconnecting the load with the power supply.

Claims

1. A ground fault circuit interrupter for preventing an overload current from a power supply to a load, comprising:

a first module supplying a unipolar ≡

power supply;

a second module obtaining a fault current in responsive to a hot wire and a neutral wire with a ground wire;

a third module amplifying a signal of said fault current from said second module;

a fourth module which comprises a programmable control module for determining said fault current, wherein when said programmable control module presets a preset threshold for said fault current to be compared;

a fifth module comprising an End-of-life circuitry performing an automatic self-checking operation;

a sixth module which comprises a control switch, a trip breaker, an armature, a locking device, a movable terminal, and a fixed terminal, wherein when said fault current is larger than said preset threshold, said programmable control module sends a control signal to said control switch such that said control switch electrifies a second coil of said trip breaker to drive an armature to actuate said locking device, so as to move said movable terminal away from said fixed terminal for electrically disconnecting said load with said power supply; and

a seventh module comprising a reset circuitry for resetting said trip breaker and a test circuitry for checking a status of said trip breaker.

2. The ground fault circuit interrupter, as recited in claim 1, wherein said test circuitry of said seventh module comprises a LED indicator producing an illuminating signal to indicate said status of said ground fault circuit interrupter, wherein when said fault current is not larger than said preset threshold that said ground fault circuit interrupter is normally operated, a slow-twinkling signal is generated, and when said fault current is larger than said preset threshold that said ground fault circuit interrupter is abnormally operated, a fast-twinkling signal is generated.

3. The ground fault circuit interrupter, as recited in claim 1, wherein said fifth module comprises a transient voltage suppressor electrically coupling with said control switch, wherein when said wires are misconnected, said control switch and said transient voltage suppressor are connected between said neutral wire and said ground wire in series connection such that an electric potential between said neutral wire and said ground wire is relatively high to conduct said transient voltage suppressor, wherein said control switch is then electrified to separate said movable terminal with said fixed terminal for electrically disconnecting said load with said power supply so as to prohibit said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

4. The ground fault circuit interrupter, as recited in claim 2, wherein said fifth module comprises a transient voltage suppressor electrically coupling with said control switch, wherein when said wires are misconnected, said control switch and said transient voltage suppressor are connected between said neutral wire and said ground wire in series connection such that an electric potential between said neutral wire and said ground wire is relatively high to conduct said transient voltage suppressor, wherein said control switch is then electrified to separate said movable terminal with said fixed terminal for electrically disconnecting said load with said power supply so as to prohibit said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

5. The ground fault circuit interrupter, as recited in claim 1, wherein a first coil of said trip breaker is not electrified to drive said armature to actuate said locking device when said neutral wire and said hot wire are reversely connected, so as to prohibit said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

6. The ground fault circuit interrupter as recited in claim 4, wherein a first coil of said trip breaker is not electrified to drive said armature to actuate said locking device when said neutral wire and said hot wire are reversely connected, so as to prohibit said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

7. The ground fault circuit interrupter, as recited in claim 1, wherein said second module comprises two zero-phase current inductors for obtaining said fault current from said hot wire to said ground wire and from said neutral wire to said ground wire, wherein one of said current inductors has a coil ratio of primary and secondary windings being set as 1:

1000 while another said current inductor has a coil ratio of primary and secondary windings being set as 1;

200.

8. The ground fault circuit interrupter, as recited in claim 6, wherein said second module comprises two zero-phase current inductors for obtaining said fault current from said hot wire to said ground wire and from said neutral wire to said ground wire, wherein one of said current inductors has a coil ratio of primary and secondary windings being set as 1:

1000 while another said current inductor has a coil ratio of primary and secondary windings being set as 1;

200.

9. A method of preventing an overload current from a power supply to a load through a ground fault circuit interrupter, comprising the steps of:

(a) obtaining an interrupted fault current from a hot wire to a ground wire via a first zero-phase current inductor and a fault current from a neutral wire to the ground wire via a second zero-phase current inductor;

(b) amplifying a signal of said fault current by an Op-Amp; and

(c) determining said fault current by a programmable control module, wherein when said fault current is larger than a preset threshold, said programmable control module sends a control signal to a control switch such that said control switch electrifies a second coil of a trip breaker to drive an armature at an unlocked position, so as to separate a movable terminal with a fixed terminal for electrically disconnecting said load with said power supply;

(d) determining said hot wire and said neutral wire are connected improperly by determining whether said hot-wire and said neutral wire are reversely connected, wherein when said hot wire and said neutral wire are reversely connected, a first coil of said trip breaker is not electrified to actuate said armature; and

(e) prohibiting said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

10. The method, as recited in claim 9, wherein said step (e) comprises a step of keeping said movable terminal away from said fixed terminal to prohibit a re-connection between said load and said power supply when said ground fault circuit interrupter is reset.

11. A method of preventing an overload current from a power supply to a load through a ground fault circuit interrupter, comprising the steps of:

(1) obtaining an interrupted fault current from a hot wire to a ground wire via a first zero-phase current inductor and a fault current from a neutral wire to the ground wire via a second zero-phase current inductor;

(2) amplifying a signal of said fault current by an Op-Amp;

(3) determining said fault current by a programmable control module, wherein when said fault current is larger than a preset threshold, said programmable control module sends a control signal to a control switch such that said control switch electrifies a second coil of a trip breaker to drive an armature at an unlocked position, so as to separate a movable terminal with a fixed terminal for electrically disconnecting said load with said power supply;

(4) performing an automatic self-checking operation to determine a status of said ground fault circuit interrupter in responsive to said fault current whether in a normal operation; and

(5) producing an illuminating signal to indicate said status of said ground fault circuit interrupter in condition that;

when said fault current is not larger than said preset threshold that said ground fault circuit interrupter is normally operated, a slow-twinkling signal is generated; and

when said fault current is larger than said preset threshold that said ground fault circuit interrupter is abnormally operated, a fast-twinkling signal is generated.

12. The method, as recited in claim 11, further comprising the step (3.1), in between said step (3) and said step (4), of determining said hot wire and said neutral wire are connected improperly;

and step (3.2) of prohibiting said ground fault circuit interrupter from being reset to re-connect said load with said power supply unless said hot wire and said neutral wire are connected properly.

13. The method, as recited in claim 12, wherein the step (3.1) further comprises the steps of:

(3.1.1) obtaining a magnitude of said fault current will flowing through said neutral wire, wherein said hot wire and said neutral wire are electrically misconnected when said magnitude of said fault current is relatively high; and

(3.1.2) electrifying said control switch to separate said movable terminal with said fixed terminal for electrically disconnecting said load with said power supply.

14. The method, as recited in claim 12, wherein said step (3.1) further comprises a step of determining whether said hot wire and said neutral wire are reversely connected, wherein when said hot wire and said neutral wire are reversely connected, a first coil of said trip breaker is not electrified to actuate said armature.

15. The method, as recited in claim 13, wherein said step (3.2) comprises a step of keeping said movable terminal away from said fixed terminal to prohibit a re-connection between said load and said power supply when said ground fault circuit interrupter is reset.

16. The method, as recited in claim 14, wherein said step (3.2) comprises a step of keeping said movable terminal away from said fixed terminal to prohibit a re-connection between said load and said power supply when said ground fault circuit interrupter is reset.