Combo AFCI/GFCI with single test button

• US 6,433,977 B1
• Filed: 04/14/2000
• Issued: 08/13/2002
• Est. Priority Date: 04/16/1999
• Status: Expired due to Term

• Current Assignee: Pass & Seymour Incorporated (Legrand SA)
• Original Assignee: Pass & Seymour Incorporated (Legrand SA)
• Inventors: Macbeth, Bruce F.
• Primary Examiner(s): HUYNH, KIM NGOC
• Application Number:
  US09/549,504
• Time in Patent Office: 851 Days
• Field of Search: 361/42, 361/45, 361/46, 361/115, 361/49, 361/50, 361/93.1, 324/536, 324/509, 324/500, 324/512
• US Class Current: 361/42
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 3/335 the main function being self testing of the device

Abstract

A combination AFCI/GFCI includes a single test button which when pushed, tests both the arc fault and ground fault detection circuitry and the circuit interrupter. Closing the test button causes a simulated ground fault and enables a signal steering circuit. The steering circuit redirects the ground fault detector output to an arc fault simulator circuit which produces a simulated arcing pulses that are coupled, preferably by way of an extra winding, to an arc fault sensor transformer. The arc fault detector senses the arc fault simulator pulses coupled to the sensor transformer and, if everything is operating normally, triggers a switching device such as an SCR which activities a circuit interrupter. In this way, both the ground fault circuit interrupter and arc fault circuit interrupter functions are tested simultaneously, and the test is initiated by a single test button. When the circuit interrupter is not in the test mode, the steering circuitry is disabled and either a ground fault or an arc fault or both will independently activate the switching device and the circuit interrupter.

Claims

1. A combination arc fault circuit interrupter and ground fault circuit interrupter having a self test feature activated by a single button comprising:

a circuit interrupter;

a ground fault detector connected to the circuit interrupter for activating the circuit interrupter when a ground fault is detected;

an arc fault detector connected to the circuit interrupter for activating the circuit interrupter when an arc fault is detected;

a steering circuit for disconnecting the output of one of the ground fault and arc fault detectors from the circuit interrupter and connecting it to the other of the arc fault and ground fault detectors; and

a test button connected to one of the arc fault detector and ground fault detector, and to the steering circuit, in which activation of the test button activates one of the arc fault detector and ground fault detectors, which in turn activates the other of the arc fault detector and ground fault detector which in turn activates the circuit interrupter;

in which the steering circuit comprises a transistor connecting the ground fault detector to the circuit interrupter when the transistor is turned on, and disconnecting the ground fault detector from the circuit interrupter when the transistor is turned off.

2. A combination arc fault circuit interrupter and ground fault circuit interrupter having a self test feature activated by a single button comprising:

a circuit interrupter;

a ground fault detector connected to the circuit interrupter for activating the circuit interrupter when a ground fault is detected;

an arc fault detector connected to the circuit interrupter for activating the circuit interrupter when an arc fault is detected;

a steering circuit for disconnecting the output of one of the ground fault and arc fault detectors from the circuit interrupter and connecting it to an input of the other of the arc fault and ground fault detectors; and

a test button connected to one of the arc fault detector and ground fault detector, and to the steering circuit, in which activation of the test button activates one of the arc fault detector and ground fault detectors, which in turn activates the other of the arc fault detector and ground fault detector which in turn activates the circuit interrupter.

3. The combination arc fault circuit interrupter and ground fault circuit interrupter of claim 2 comprising an input of an arc fault simulating circuit connected to an output of the ground fault detector.

4. The combination arc fault circuit interrupter and ground fault circuit interrupter of claim 2 comprising an input of an ground fault simulating circuit connected to an output of the arc fault detector.

7. The combination arc fault circuit interrupter and ground fault circuit interrupter of claim 2 in which the ground fault detector comprises a sensor coupled to a circuit being protected, and the test button is connected to the circuit being protected to cause a current imbalance in the circuit being protected when the button is activated.

5. The combination arc fault circuit interrupter and ground fault circuit interrupter having a self test feature activated by a single button comprising:

a circuit interrupter;

a ground fault detector connected to the circuit interrupter for activating the circuit interrupter when a ground fault is detected;

an arc fault simulating circuit connected to an output of the ground fault detector;

an arc fault detector connected to the circuit interrupter for activating the circuit interrupter when an arc fault is detected;

a steering circuit for disconnecting the output of one of the ground fault and arc fault detectors from the circuit interrupter and connecting it to the other of the arc fault and ground fault detectors; and

a test button connected to one of the arc fault detector and ground fault detector, and to the steering circuit, in which activation of the test button activates one of the arc fault detector and ground fault detectors, which in turn activates the other of the arc fault detector and ground fault detector which in turn activates the circuit interrupter;

in which the arc fault simulating circuit comprises an SCR having a gate terminal connected to the output of the ground fault detector and a switched terminal connected to the arc fault detector.

6. A combination arc fault circuit interrupter and ground fault circuit interrupter having a self test feature activated by a single button comprising:

a circuit interrupter;

a ground fault detector connected to the circuit interrupter for activating the circuit interrupter when a ground fault is detected;

an arc fault detector connected to the circuit interrupter for activating the circuit interrupter when an arc fault is detected;

a ground fault simulating circuit connected to an output of the arc fault detector;

a steering circuit for disconnecting the output of one of the ground fault and arc fault detectors from the circuit interrupter and connecting it to the other of the arc fault and ground fault detectors; and

a test button connected to one of the arc fault detector and ground fault detector, and to the steering circuit, in which activation of the test button activates one of the arc fault detector and ground fault detectors, which in turn activates the other of the arc fault detector and ground fault detector which in turn activates the circuit interrupter;

in which the ground fault simulating circuit comprises an SCR having a gate terminal connected to the output of the arc fault detector and a switched terminal connected to the ground fault detector.

8. A combination arc fault circuit interrupter and ground fault circuit interrupter in which activating a single test button tests both the arc fault and ground fault interruption capability at the same time including:

a ground fault sensor;

a ground fault detector connected to the ground fault sensor;

an arc fault sensor coupled to the circuit being protected;

an arc fault detector coupled to the arc fault sensor;

an arc fault simulator circuit coupled to the arc fault sensor;

a ground fault simulator circuit coupled to the circuit being protected;

a test button connected to the ground fault simulator;

a circuit interrupter connected to the ground fault detector and to the arc fault detector for interrupting the circuit being protected if either a ground fault or an arc fault is detected;

a steering circuit which prevents the ground fault detector from activating the circuit interrupter;

in which activation of the test button activates the ground fault simulator circuit, which in turn activates the ground fault detector, which in turn activates the arc fault simulator circuit, which in turn introduces an arc fault simulated signal into the arc fault sensor, which in turn activates the arc fault detector which activates the circuit interrupter.

9. A combination arc fault circuit interrupter and ground fault circuit interrupter in which activating a single test button tests both the arc fault and ground fault interruption capability at the same time including:

a ground fault sensor;

a ground fault detector connected to the ground fault sensor;

an arc fault sensor coupled to the circuit being protected;

an arc fault detector coupled to the arc fault sensor;

an arc fault simulator circuit coupled to the arc fault sensor;

a ground fault simulator circuit coupled to the circuit being protected;

a test button connected to the arc fault simulator;

a circuit interrupter connected to the ground fault detector and to the arc fault detector for interrupting the circuit being protected if either a ground fault or an arc fault is detected;

a steering circuit which prevents the arc fault detector from activating the circuit interrupter;

in which activation of the test button activates the arc fault simulator circuit, which in turn activates the arc fault detector, which in turn activates the ground fault simulator circuit, which in turn introduces a ground fault simulated signal into the ground fault sensor, which in turn activates the ground fault detector which activates the circuit interrupter.

10. A combination arc fault circuit interrupter and ground fault circuit interrupter in which activating a single test button tests both the arc fault and ground fault interruption capability at the same time, comprising:

a ground fault sensor;

a ground fault detector connected to the ground fault sensor;

an arc fault sensor coupled to the circuit being protected;

an arc fault detector coupled to the arc fault sensor;

an arc fault simulator circuit coupled to the arc fault sensor;

a ground fault simulator circuit coupled to the circuit being protected;

a test button connected to the ground fault simulator;

a circuit interrupter connected to the ground fault detector and to the arc fault detector for interrupting the circuit being protected if either a ground fault or an arc fault is detected;

in which activation of the test button activates the ground fault simulator circuit, which in turn activates the ground fault detector, which in turn activates the arc fault simulator circuit, which in turn introduces an arc fault simulated signal into the arc fault sensor, which in turn activates the arc fault detector which activates the circuit interrupter; and

in which the arc fault sensor comprises a transformer serving as a combination grounded neutral dormant oscillator and arc fault sensor in which hot and neutral load wires of a circuit being protected form one turn primaries.

11. A combination arc fault circuit interrupter and ground fault circuit interrupter in which activating a single test button tests both the arc fault and ground fault interruption capability at the same time, comprising:

a ground fault sensor;

a ground fault detector connected to the ground fault sensor;

an arc fault sensor coupled to the circuit being protected;

an arc fault detector coupled to the arc fault sensor;

an arc fault simulator circuit coupled to the arc fault sensor;

a ground fault simulator circuit coupled to the circuit being protected;

a test button connected to the arc fault simulator;

a circuit interrupter connected to the ground fault detector and to the arc fault detector for interrupting the circuit being protected if either a ground fault or an arc fault is detected;

in which activation of the test button activates the arc fault simulator circuit, which in turn activates the arc fault detector, which in turn activates the ground fault simulator circuit, which in turn introduces a ground fault simulated signal into the ground fault sensor, which in turn activates the ground fault detector which activates the circuit interrupter; and

in which the arc fault sensor comprises a transformer serving as a combination grounded neutral dormant oscillator and arc fault sensor in which hot and neutral load wires of a circuit being protected form one turn primaries.