SURGE PROTECTION APPARATUS WITH IMPROVED CIRCUIT FOR RELIABLE SPARKOVER

• US 3,611,044 A
• Filed: 06/30/1970
• Issued: 10/05/1971
• Est. Priority Date: 06/30/1970
• Status: Expired due to Term

• Current Assignee: Joseph C. Osterhout, Richard E. Kennon
• Original Assignee: Joseph C. Osterhout, Richard E. Kennon
• Inventors: Osterhout, Joseph C., Kennon, Richard E.
• Primary Examiner(s): Trammell, James D.
• Application Number:
  US05/051,096
• Time in Patent Office: 462 Days
• Field of Search: 317/70,61,61.5,68 315/36
• US Class Current: 361/128
• CPC Class Codes: H01T 4/20 Arrangements for improving potential distribution
• CPC Class Codes: H02H 9/06 using spark-gap arresters

Abstract

Surge protection apparatus such as a lightning arrester is provided with a plurality of serially connected, power-handling spark gaps with a network of voltage-grading capacitors connected thereacross. A control spark gap is connected across one of the power-handing spark gaps and has a controlled and reliable sparkover characteristic. In circuit with the control spark gap are inductive and capacitive circuit elements to assure sparkover of the entire series string of power-handling spark gaps quickly upon sparkover of the control spark gap while avoiding damage to the control spark gap from excessive current flow.

Claims

1. An electrical surge arrester comprising:

a serially connected plurality of power-handling spark gaps;

a first circuit branch electrically connected across at least one of said power-handling spark gaps, said first circuit branch comprising a voltagegrading capacitor;

a second circuit branch electrically connected across said at least one power-handling spark gap, said second circuit branch comprising a control spark gap and inductive and capacitive impedance means for assuring rapid breakdown of said plurality of power-handling spark gaps upon breakdown of said control spark gap.

2. The subject matter of claim 1 wherein:

said impedance means comprises an inductance element having an inherent resistance and a capacitance element;

said inherent resistance of said inductance element being substantially the only resistance in said first and second circuit branches.

3. The subject matter of claim 1 wherein:

said impedance means comprises serially connected inductive and capacitive elements.

4. The subject matter of claim 2 further comprising:

a resistance element connected in a capacitor discharge path across at least said capacitance element of said second circuit branch.

5. A lightning arrester comprising:

a plurality of power-handling spark gaps in a first series connection between two circuit points;

a plurality of voltage-grading capacitors in second and third series connections between said two circuit points, and capacitors of said second and third series connections having successively alternating connections to said first series connection of power-handling spark gaps;

one of said capacitors of said second and third series connections also being connected in a circuit loop with a control spark gap and inductive and capacitive impedance elements.

6. The subject matter of claim 5 wherein:

said inductive and capacitive impedance element are in series connection with said control spark gap.

7. The subject matter of claim 5 further comprising:

a fourth series connection between said two circuit points comprising a plurality of resistors, each of the order of megohms, each connected across one of said plurality of power-handling spark gaps;

said first series connection including resistors of substantially smaller magnitude than those of said fourth series connection connected between adjacent ones of said plurality of power-handling spark gaps.