Apparatus for fault detection and isolation

• US 5,237,480 A
• Filed: 07/29/1992
• Issued: 08/17/1993
• Est. Priority Date: 02/26/1990
• Status: Expired due to Fees

• Current Assignee: Seiscor Technologies, Inc.
• Original Assignee: Seiscor Technologies, Inc.
• Inventors: Dara, Paul S.
• Primary Examiner(s): DEBOER, TODD
• Application Number:
  US07/919,398
• Time in Patent Office: 384 Days
• Field of Search: 361/42, 361/59, 361/74, 361/86, 361/88, 361/91, 361/92, 361/56
• US Class Current: 361/42
• CPC Class Codes: H02H 3/04 with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned watching of pilot wires H02H1/0084; protection of protective arrangements H02H7/008; indication of the state of electronic switches H03K17/18
• CPC Class Codes: H02H 3/066 Reconnection being a consequence of eliminating the fault which caused disconnection
• CPC Class Codes: H02H 3/087 for dc applications

Abstract

An apparatus for fault detection and coupled between a power supply line and a circuit to be powered. When a fault develops in the circuit that causes voltage in the power supply lines to decrease, the power being provided is interrupted from the circuit. Once the fault is removed, power is automatically returned to the circuit.

Claims

1. Apparatus for interrupting power comprising:

electronic circuitry;

a main power supply line adapted for providing a preset voltage level to said electronic circuitry;

a reference power line providing a reference voltage;

an opto-coupler comprising a light emitting diode having a first terminal and second terminal, and a photo-transistor responsive to said light emitting diode and having a first terminal and a second terminal;

said reference power line being coupled to said photo-transistor first terminal and said light emitting diode first terminal;

said light emitting diode second terminal being coupled to said main power supply line at said electronic circuitry;

said light emitting diode illuminating in response to a voltage level drop from said reference power line to said main power supply line at said electronic circuitry;

said photo-transistor first terminal being coupled to said photo-transistor second terminal when said light emitting diode illuminates and said photo-transistor first terminal being de-coupled from said photo-transistor second terminal when said light emitting diode does not illuminate;

a relay comprising a coil and a switch, said switch having a first terminal and a second terminal, said switch first terminal being electrically coupled to said main power supply line and said switch second terminal being electrically coupled to said electronic circuitry;

said coil being electrically coupled to said photo-transistor second terminal, said coil being energized when said photo-transistor first terminal is coupled to said photo-transistor second terminal and said coil being de-energized when said photo-transistor first terminal is decoupled from said photo-transistor second terminal; and

said switch first terminal being coupled to said switch second terminal when said coil is de-energized, said switch first terminal being decoupled from said switch second terminal when said coil is energized.

2. The apparatus as recited in claim 1 wherein said switch further comprises a third terminal, said switch first terminal being coupled to said switch third terminal when said coil is energized;

and wherein said apparatus further comprises a second light emitting diode coupled to said third terminal, said second light emitting diode illuminating when said switch first terminal is coupled to said switch third terminal.