Intelligent ground fault circuit interrupter

• US 6,111,733 A
• Filed: 01/14/1998
• Issued: 08/29/2000
• Est. Priority Date: 05/04/1995
• Status: Expired due to Term

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Neiger, Benjamin, Gershen, Bernard, Rosenbaum, Saul
• Primary Examiner(s): Jackson, Stephen W.
• Application Number:
  US09/288,081
• Time in Patent Office: 958 Days
• Field of Search: 361/42, 361/45, 361/115, 361/93.1, 361/49, 361/50
• US Class Current: 361/42
• CPC Class Codes: H02H 1/04 Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02H 11/002 in case of inverted polarity or connection; with switching for obtaining correct connection
• CPC Class Codes: H02H 3/05 with means for increasing reliability, e.g. redundancy arrangements for logic circuits H03K19/003
• CPC Class Codes: H02H 3/335 the main function being self testing of the device
• CPC Class Codes: H02H 3/337 avoiding disconnection due to reactive fault currents
• CPC Class Codes: H02H 3/338 also responsive to wiring error, e.g. loss of neutral, break
• CPC Class Codes: H02H 3/44 responsive to the rate of change of electrical quantities

Abstract

An intelligent circuit interrupt system is electrically connected between an AC source and a load for interrupting a flow of AC from the source to the load upon detection of an interrupt condition. A circuit interrupter electrically connected to phase and neutral terminals of the AC source defines the interrupt condition. A relay switch with a relay coil and phase and neutral contacts is included such that line and load ends of the phase contact are electrically connected, respectively, between the interrupt means load side phase port and a phase terminal of the load. Line and load ends of the neutral contact are electrically connected, respectively, between the interrupt neutral port and a neutral terminal of the load. The relay coil is electrically coupled between load sides of said phase and neutral contacts for controlling the contacts in response to the interrupt signal. An open-contact miswiring detector (OCMD) is electrically connected to one of the phase and neutral contacts for detecting a miswiring condition when the contacts are in an open state, and a closed-contact miswiring detector (CCMD) is electrically connected to the OCMD and to one of the neutral and phase contacts for detecting a miswiring condition when the contacts are in a closed state. A timing signal generator generates system timing signals. A test circuit electrically coupled to the interrupt means and the timing signal generator tests the interrupt means operability. An alarm circuit is electrically responsive to the test circuit, the timing signal generator, the OCMD and the CCMD for communicating an open-contact miswiring condition, a closed-contact miswiring condition, an operational failure condition, and a need for external testing condition. A power supply is electrically connected between the load ends of the phase and neutral contacts, and to the timing signal generator.

Claims

1. An intelligent circuit interrupt system electrically disconnecting a load from a source of AC power upon detection of any interrupt condition, comprising:

a. circuit interrupt means including line and load side phase and neutral ports, wherein said line side phase and neutral ports are electrically connection, respectively, to phase and neutral terminals of said AC power source and said circuit interrupt means generates an interrupt signal for interrupting said AC power flow upon the detection of said interrupt condition;

b. a relay switch including a relay tripping coil and phase and neutral contacts, wherein line and load ends of said phase contact are electrically connected, respectively, between said interrupt means load side phase port and a phase terminal of said load and the line and load ends of said neutral contact are electrically connected, respectively, between said interrupt means load side neutral port and a neutral terminal of said load and said relay tripping coil is electrically coupled between said load ends of said phase and neutral contacts for controlling said contacts in response to said interrupt signal;

c. an open-contact miswiring detector (OCMD) electrically connected to said line and load ends of one of said phase and neutral contacts for detecting a miswiring condition when said contacts are in an open state;

d. a closed-contact miswiring detector (CCMD) electrically connected to said load end of said phase contact and to said line and load ends of one of said phase and neutral contacts for detecting a miswiring condition when said contacts are in a closed state;

e. a timing signal generator electrically connected to said open and closed contact miswiring detectors for generating system timing signals;

f. a test circuit electrically couple to said interrupt means and responsive to said timing signal generator for regularly testing said interrupt means operability;

g. an alarm circuit electrically responsive to each of said test circuit, said timing signal generator, said open-contact miswiring detector and said closed-contact miswiring detector for producing an alarm signal communicating at lease one of an open-contact miswiring condition, a closed-contact miswiring condition, an operational failure condition and a need for external testing condition;

h. a power supply electrically connected between said load ends of said phase and neutral contacts and to said timing signal generator;

i. control means coupled to said circuit interrupt means to receive said interrupt signal and coupled to said relay tripping coil to provide operating current to said relay tripping coil when said control means is conducting current;

j. alternative control means coupled to said alarm circuit to receive said alarm signal and to said relay tripping coil to provide operating current to said relay tripping coil in the event that said control means fails to operate.

2. An intelligent circuit interrupt system, as defined in claim 1, wherein said alternative control means is an optoelectronic switch.

3. An intelligent current interrupt system, as defined in claim 2, wherein said optoelectronic switch comprises a photo diode and a phototransistor.

4. An intelligent current interrupt systems, as defined in claim 3, wherein said alarm signal is coupled to said photo diode to cause said photo diode to emit light which is received by said phototransistor and said phototransistor is made conductive to supply operating current to said relay tripping coil.