Semi-conducting layer for insulated electrical conductors

• US 5,036,165 A
• Filed: 07/23/1990
• Issued: 07/30/1991
• Est. Priority Date: 08/23/1984
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Elton, Richard K., Schultz, William R. Jr.
• Primary Examiner(s): NIMMO, MORRIS
• Application Number:
  US07/555,713
• Time in Patent Office: 372 Days
• Field of Search: 174/102 SC, 174/105 SC, 174/106 SC, 174/120 SC
• US Class Current: 174/102.0SC
• CPC Class Codes: H02K 2203/15 Machines characterised by cable windings, e.g. high-voltage cables, ribbon cables
• CPC Class Codes: H02K 3/40 for high voltage, e.g. affording protection against corona discharges
• CPC Class Codes: Y10S 174/28 Plural semiconductive layers

Abstract

A semi-conducting pyrolyzed glass fiber layer equalizes the electrical potential on the exterior surface of an insulated conductor when the layer covers the surface. The layer prohibits the development of a corona discharge and bleeds off any electrical charge developed thereon when the layer is electrically coupled to a body having a known potential. The insulated conductor may be windings in a dynamoelectric machine.

Claims

1. A cable adapted to carry electrical current therein comprising:

an electrical conductor;

an insulator substantially surrounding said conductor, and

an internal grading layer including a semi-conducting pyrolyzed organic material and glass fiber layer having a resistivity in the range of 200 to 10,000,000 ohms per square in electrical contact with said conductor.

2. A cable as in claim 1 further including means for maintaining a substantially uniform electrical potential over said cable'"'"'s expanse which includes a semi-conducting pyrolyzed organic material and glass fiber layer, having a resistivity in the range of 200 to 10,000,000 ohms per square, being in intimate contact with the exterior surface of said insulator and being in electrical contact with a coupling means having a predetermined electrical potential.