ELECTRICAL LEAKAGE DETECTING DEVICE

• US 3,786,466 A
• Filed: 03/17/1972
• Issued: 01/15/1974
• Est. Priority Date: 03/19/1971
• Status: Expired due to Term

• Current Assignee: Hiro Sato, Ryoji Kasama, Shotaro Naito
• Original Assignee: Hiro Sato, Ryoji Kasama, Shotaro Naito
• Inventors: Naito, Shotaro, Kasama, Ryoji, Sato, Hiro
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Myer, Daniel
• Application Number:
  US05/235,482
• Time in Patent Office: 669 Days
• Field of Search: 340/255 317/27R,33SC,16
• US Class Current: 340/651
• CPC Class Codes: G01M 3/40 by using electric means, e.g. by observing electric discharges
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

A leakage detecting circuit for detecting leakage from a source of power, for example, a battery to a source of reference potential, for example, ground, which comprises a pair of voltage detecting circuits respectively connected to the positive and negative terminals of the battery to ground through first and second switching means respectively. The battery is insulated from ground, so that if a leakage path exists between the battery and ground, an electrical circuit is closed which includes a voltage detection device and one of the switching means. A voltage is thus applied to the voltage detecting device by closing the switching device. In normal operation, the circuit is open so that no voltage is applied to the voltage detecting device. In alternative embodiments, the voltage detecting devices comprise a neon tube and a photoconductor element responsive to the neon tube, or a coil in circuit with a Hall element.

Claims

1. A leakage detecting circuit for detecting leakage from a source of power to a source of reference potential, said leakage detecting circuit comprising:

a source of power including a positive terminal and a negative terminal;

a first series circuit means comprising a first detecting means and a first switching means;

a second series circuit means comprising a second detecting means and a second switching means; and

a control circuit for operating the first and second switching means alternatively;

said first series circuit means and said second series circuit means being connected in series between said positive and negative terminals of the power source, the connection between said first and second series circuit means being connected electrically to the source of reference potential;

the first series circuit means being actuated by operating the first switching means whereby, when a leakage from the source of power to the source of reference potential occurs, a first circuit path having the first series circuit means, the terminal of the power source, the leakage, and the reference source is established;

the second series circuit means being actuated by operating the second switching means whereby, when a leakage from the source of power to the source of reference potential occurs, a second circuit path having a second series circuit means, the terminal of the power source, the leakage and the reference source is established.

2. The circuit as set forth in claim 1 wherein said first and said second Detecting means are each voltage detecting means respectively connected in series with said first and said second switching means.

3. The circuit as set forth in claim 2 wherein said source of reference potential is ground.

4. The circuit as set forth in claim 1 wherein said first and said second switching means are thyristors and said control circuit includes means for alternately actuating said thyristors.

5. The circuit as set forth in claim 4 wherein said source of power is a battery comprising a plurality of cells.

6. The circuit as set forth in claim 1 further including a first indicating means operatively connected to the output terminal of said first detecting means and a second indicating means operatively connected to said second detecting means.

7. The circuit as set forth in claim 6 wherein the relative magnitudes of the outputs of said first and second indicating means provide an indication of the location of the leakage of said source of power to said source of reference potential.

8. The circuit as set forth in claim 6 wherein the inputs of each of said detecting means are respectively electrically isolated from the outputs thereof.

9. The circuit as set forth in claim 2 wherein each of said first and said second detecting means comprises a neon tube and a photoconductive element responsive to said neon tube.

10. The circuit as set forth in claim 2 wherein each of said first and said second detecting means comprises a coil and a Hall element operatively responsive to the flux generated by said coil.

11. The circuit as set forth in claim 1 further including indicating means operatively connected to both of said first detecting means and said second detecting means.