Combined fault and voltage indicator

• US 4,251,770 A
• Filed: 06/25/1979
• Issued: 02/17/1981
• Est. Priority Date: 06/25/1979
• Status: Expired due to Term

• Current Assignee: Edmund O. Schweitzer Jr
• Original Assignee: Edmund O. Schweitzer Jr
• Inventors: Schweitzer, Edmund O. Jr.
• Primary Examiner(s): Moore, David K.
• Application Number:
  US06/051,402
• Time in Patent Office: 603 Days
• Field of Search: 324/133, 324/120, 324/51, 324/122, 324/127, 324/52, 340/664, 340/650, 340/651, 340/654, 340/660
• US Class Current: 324/133
• CPC Class Codes: G01R 19/155 Indicating the presence of voltage
• CPC Class Codes: G01R 19/16509 using electromagnetic relays, e.g. reed relay magnetically driven reeds G01R9/06

Abstract

A combined fault and voltage indicator includes a rotatably-mounted target viewable from the exterior of the indicator for indicating the occurrence of a fault and a lamp viewable from the exterior of the indicator for indicating system operating voltage. The target is positioned in a reset-indicating state by a reset circuit which periodically energizes a first winding to position a permanent magnet mounted for rotation with the target. Upon occurrence of a fault circuitry within the indicator energizes a second winding to reposition the target to a fault-indicating position. The lamp is caused to flash at a rate which indicates the operating voltage of the system.

Claims

1. A combined fault and voltage indicator for indicating the occurrence of a fault current and the presence of a voltage in an alternating current conductor, comprising, in combination:

a housing adapted for mounting on said conductor;

status indicating means within said housing having reset-indicating and fault-indicating states discernible from the exterior of said housing;

fault detecting means within said housing responsive to the occurrence of a fault current in the conductor for conditioning said status indicating means to said fault indicating state;

reset circuit means within said housing periodically operable from an applied unidirectional current for conditioning said status indicating means to said reset indicating state;

a unidirectional current source within said housing operable from alternating current in said electrical conductor, the output voltage of said source being dependent on the voltage level of said alternating current, said unidirectional current source including a rectifier network having input and output terminals, one of said input terminals being capacitively coupled to said conductor and the other of said input terminals being connected to ground, and a first capacitor connected across said output terminals; and

voltage indicating circuit means within said housing comprising a gas-discharge lamp visible from the exterior of said housing, and a second capacitor, said discharge lamp and said second capacitor being connected in series between said output terminals of said rectifier network, and said reset circuit means being connected across said second capacitor, whereby said periodic operation of said reset circuit periodically discharges said second capacitor and said discharge lamp periodically conducts to recharge said second capacitor, the rate of said periodic conduction being dependent on the voltage level in the conductor.

2. A combined fault and voltage indicator as defined in claim 1 wherein said fault detecting means comprise fault circuit means operable from an applied unidirectional current for conditioning said status indicating means to said reset state, and wherein said fault circuit means are connected across said second capacitor.

3. A combined fault and voltage indicator as defined in claim 2 wherein said fault circuit means includes a third capacitor, and means including a diode connected between said second capacitor and said third capacitor for preventing said reset circuit from discharging said third capacitor upon said periodic operation thereof.

4. A combined fault and voltage indicator as defined in claim 1 wherein said gas-discharge lamp is a neon lamp.

5. A fault indicator as defined in claim 1 wherein said status indicating means comprise a mechanical flag member having a first position corresponding to said reset-indicating state, and a second position corresponding to said fault-indicating state, and wherein said reset circuit means include a winding for generating a magnetic field for positioning said mechanical member to said reset-indicating state.

6. A combined fault and voltage indicator for indicating the occurrence of a fault current and the presence of a voltage in an electrical conductor, comprising, in combination:

a housing adapted for mounting on said conductor;

status indicating means within said housing comprising a target member having a reset-indicating position and a fault-indicating position discernible from the exterior of said housing;

fault detecting circuit means within said housing including a winding in magnetic communication with said target member for positioning said target member to said fault-indicating position in response to the occurrence of a fault current in the conductor, said fault circuit means being operable from an applied unidirectional current;

reset circuit means within said housing including a winding in magnetic communication with said target member for positioning said target member to said reset position, said reset circuit means being periodically operable from an applied unidirectional current;

a unidirectional current source within said housing operable from alternating current in said electrical conductor, the output voltage of said source being dependent on the voltage level of said alternating current, said unidirectional current source including a rectifier network having input and output terminals, one of said input terminals being capacitively coupled to said conductor and the other of said input terminals being connected to ground, and a first capacitor connected across said output terminals; and

voltage indicating circuit means within said housing comprising a gas-discharge lamp visible from the exterior of said housing, and a second capacitor, said discharge lamp and said second capacitor being connected in series between said output terminals of said rectifier network, and said reset circuit means being connected across said second capacitor, whereby said periodic operation of said reset circuit periodically discharges said second capacitor and said discharge lamp periodically conducts to recharge said second capacitor, the rate of said periodic conduction being dependent on the voltage level in the conductor.

7. A combined fault and voltage indicator as defined in claim 6 wherein said fault detecting circuit means include a third capacitor and means including a diode serially connected between second capacitor and said third capacitor for preventing said reset circuit from discharging said third capacitor upon said periodic operation thereof.

8. A combined fault and voltage indicator as defined in claim 6 wherein said gas discharge lamp is a neon lamp.