Loop resistance tester (LRT) for cable shield integrity
US6225810A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 1998 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Feb 12, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A loop resistance tester (LRT) for shield integrity testing comprising three elements: a "drive" current coupler, a "sense" current coupler, joint probes, and an instrument assembly. A low-power excitation current is sent from the instrument into the drive coupler, which is essentially a transformer. This induces a current in the electrical cable under test, as long as that cable and the connected structure form a continuous current path, or loop. This induced loop current is detected by the "sense" current coupler (transformer) and is measured by the instrument. The ratio of the loop voltage to loop current, as phasor values, gives the complex loop impedance, the real part of which is the loop resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.