Ground skew protection method and apparatus
US5671110A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 1996 |
| Grant date | Sep 23, 1997 |
| Priority date | — |
| Expiry date | Jan 23, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are provided for protecting a non-isolated data communications cable against ground skew used with an AC power source. A current summing transformer is coupled to an AC power source. The current summing transformer includes a single transformer core and a plurality of coils. One of the coils is connected in series with each phase, neutral (if present) and ground line in the AC power source. The plurality of coils are substantially identical. Each coil has an identical number of turns and an identical direction of winding on the transformer core. The current summing transformer is only needed in the power path to one of two or more interconnected systems. The current summing transformer introduces a high impedance to surge current in the data cable ground of one or many non-isolated data cables attached to the system and at the same time offers substantially zero impedance to the normal power currents including leakage and fault ground currents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.