Method and apparatus for three-phase sensing using two current transformers
US5815357A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1997 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Apr 9, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus is disclosed for complete three-phase sensing using two current transformers. Two phases of a three-phase system are used as the primary windings in each current transformer such that each current transformer produces a phasor representation of a sum of the two phases. A three phase sensor is provided to add the phasor representations produced by each of the current transformers and to produce a third phasor representation from the summation. The three phasor representations can then be applied to any conventional overload relay control to monitor each phase and produces a trip signal to open the three-phase system when a phasor representation exceeds some predetermined value, or the magnitudes of the phasors differ by more than a predefined value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.