Interrupter

Abstract: Arcing in an AC power system is detected by monitoring the power waveform for wideband high-frequency noise, and examining the detected noise for patterns of variation in its amplitude synchronized to the power waveform. A narrowband, swept-frequency detector and synchronous averaging may be employed to improve discrimination of arc noise from background interference. An arcing fault interrupter for controlling a single circuit, and a whole house monitor, for detecting arcing anywhere in a house, are described.

Abstract: A long-standing expert on electric-shock hazards summarizes the studies that determined the effective body impedance under varying conditions. He describes perception currents, reaction currents, let-go currents, and fibrillating currents. Turning to means for reducing low-voltage (120-240-volt) hazards, double insulation, shock limitation, isolation transformers, and the use of either high frequency or direct current are discussed for various environments. Macroshock is always a hazard in the home, in industry, and in the hospital. But the extreme vulnerability to microshock of patients with cardiac catheters, for example, requires special precautions in intensive-care and coronary-care units. Equipment such as the ground-fault interrupter (GFI) and a special isolation transformer are cited.

Abstract: An electronic circuit interrupter digital display and keypad device includes a display to view circuit breaker settings and a keypad to select settings and values to be displayed. The display and keypad device removably connects to an electronic trip unit within the circuit interrupter by means of a plug-in connector.

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.