Intelligent ground fault circuit interrupter

• US 5,715,125 A
• Filed: 01/28/1997
• Issued: 02/03/1998
• Est. Priority Date: 05/04/1995
• Status: Expired due to Term

• Current Assignee: Leviton Manufacturing Company Incorporated
• Original Assignee: Leviton Manufacturing Company Incorporated
• Inventors: Gershen, Bernard, Neiger, Benjamin, Rosenbaum, Saul
• Primary Examiner(s): Young, Brian K.
• Assistant Examiner(s): JACKSON, STEPHEN W
• Application Number:
  US08/790,037
• Time in Patent Office: 371 Days
• Field of Search: 361/42, 361/45, 361/93, 361/115, 361/49, 361/50, 340/650
• 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 connected between an AC source and a load for interrupting a flow of AC power from said source to said load upon detection of an 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 connected, respectively, to phase and neutral terminals of said AC source and said circuit interrupt means generates an interrupt signal for interrupting said AC flow at detection of said interupt condition;

b) an electrical load having a load phase terminal and a load neutral terminal;

c) a relay switch including a relay coil and phase and neutral contacts wherein when said phase and neutral contacts are in a first position connect said load side phase and neutral ports of said circuit interrupt means to said load phase and neutral terminals, respectively, and when in a second position disconnect said load side phase and neutral ports of said circuit interrupt means from said load phase and neutral terminals;

d) control means coupled to said circuit interrupt means to receive said interrupt signal and produce a first control signal;

e) said relay coil coupled to said control means to move said phase and neutral contacts to said second position upon the receipt of said first control signal;

f) a timing circuit to produce a 1 HR signal every hour and a 2 HR signal every two hours;

g) detector means coupled to said AC source for producing a second control signal at a predetermined phase angle of the AC source wave;

h) test means coupled to said timing current to receive said 1 HR signal and to said detector means to receive said second control signal to produce a first test signal; and

i) said test means further coupled to said control means to cause said control means to produce said first control signal in response to said first test signal;

whereby current from said AC source is permitted to flow in said control means and said relay coil without the operation of said circuit interrupt means in order to test the proper operation of said control means and said relay coil.

2. An intelligent circuit interrupter system, as defined in claim 1, wherein said second control signal is produced at approximately the 170°

phase angle of the positive half wave of the AC source wave.

3. An intelligent circuit interrupter system, as defined in claim 1, wherein said control means is a silicone controlled rectifier.

4. An intelligent circuit interrupter system, as defined in claim 1, wherein said second control signal is produced at a phase angle of the positive half wave of the AC source wave where there is insufficient power to operate said circuit interrupter means.

5. An intelligent circuit interrupter system, as defined in claim 1, further comprising:

a) disabling means for producing a disabling signal coupled to said control means and said test means, said disabling signal when produced preventing the operation of said control means and the production of said first control signal;

b) means coupled to said current interrupt means and said test means to provide a short term ground fault indication upon the application of a second test signal from said test means;

c) said test means producing a second test signal upon receipt of said 2 HR signal from said timing circuit; and

d) said test means second test signal causing said disabling means to produce said disabling signal to prevent operation of said control means and prevent the operation of said relay coil due to the absence of said first control signal and cause a short term ground fault indicator to be applied to said circuit interrupt means whereby the operation of said circuit interrupter means can be verified without operating said relay switch to move said phase and neutral contacts to said second position.