Cable monitoring system with multiple branch terminations
US5708364A · kind A · utility
Inventors
Key dates
| Filing date | Aug 2, 1995 |
| Grant date | Jan 13, 1998 |
| Priority date | — |
| Expiry date | Aug 2, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/58
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A novel method and apparatus are used for monitoring cables for wear and damage. The system is particularly applicable to a cable system with multiple branch terminations. The cables have detection conductors, for example the metal cable jackets or other detection conductors extending the length of the conductors. These are connected electrically at the splice points in the system. At the end of each branch and at the end of the main cable, the detection conductors are each connected to a novel termination circuit. In the normal monitoring mode, the termination circuit appears as an open circuit. A DC voltage is normally applied to the detection conductors. Any current is a result of current leakage at a resistive fault along the detection conductors. The termination circuits are activated by altering the DC voltage, e.g. by reversing the polarity and increasing the magnitude of the voltage. This causes the termination circuit to perform a series of functional tests. These include a loop test which places a short across the end of the detection conductor for a timed period. The resulting high level loop current is used to calculate the total detection conductor resistance. A second…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.