APPARATUS FOR LOCATING CONDUCTOR DISCONTINUITY IN SEMI-CONDUCTING SHIELDED CABLE

• US 3,694,736 A
• Filed: 03/16/1971
• Issued: 09/26/1972
• Est. Priority Date: 03/16/1971
• Status: Expired due to Term

• Current Assignee: USX Corporation
• Original Assignee: Frederick W. Wakefield
• Inventors: Wakefield, Frederick W.
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US05/124,890
• Time in Patent Office: 560 Days
• Field of Search: 324/51,54
• US Class Current: 324/519
• CPC Class Codes: G01R 31/59 while the cable continuously passes the testing apparatus, e.g. during manufacture

Abstract

Detection of conductor discontinuity location in a semiconducting shielded electric cable. The cable is passed over spaced apart electrical contacts providing an alternating current through the shield between the contacts. As the cable is moved over the contacts, a capacitance coupled current is induced in the conductor and a change in the current locates the discontinuity as it passes the electrical contacts.

Claims

1. Apparatus for locating a conductor discontinuity in an electric cable with a semi-conducting sheath comprising a pay-off reel supporting a length of cable to be tested, a take-up reel spaced away from said pay-off reel, three aligned and equally spaced apart electrical contacts with the outer contacts connected to ground, a source of alternating current power connected to said contacts so that an alternating current flows in said sheath between the center contact and the outer contacts as the cable passes from the pay-off reel to the take-off reel and over said contacts, means on said takeup reel for grounding the leading end of said conductor, an ammeter, and circuit means connecting said ammeter between ground and the trailing end of the conductor under test on said pay-off reel whereby when said cable is passed from said pay-off reel to said takeup reel and a conductor discontinuity passes said contact next to said pay-off reel, a capacitance coupled current will flow in said conductor between the discontinuity and the trailing end and reach a maximum value when said discontinuity reaches said contact next to said takeup reel thereby locating said discontinuity at the center contact when said ammeter indicates half the maximum capacitance coupled current is flowing.

2. Apparatus according to claim 1 in which said contacts are pulleys over which said cable passes and which includes alarm means connected to said circuit means and responsive to the flow of said capacitance coupled current and means connected to said alarm means for adjusting the response level of said alarm means.