Circuit for controlling the orientation of a magnetic field
US5105326A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1991 |
| Grant date | Apr 14, 1992 |
| Priority date | — |
| Expiry date | May 31, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H71/32
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit for controlling the orientation of magnetic fields is provided. The circuit has particular application to a flux shunt trip device in a circuit breaker. The flux shunt trip device has a spring-loaded plunger which when released to its extended position causes the circuit breaker to trip. Under normal operating conditions, the plunger is maintained in a retracted position by the force of a permanent magnet. A trip coil is mounted adjacent to the plunger. When the trip coil is energized a magnetic flux is generated opposing the magnetic flux of the permanent magnet. When the opposing flux neutralizes the flux of the permanent magnet the spring-loaded plunger is released to its trip position. A control circuit is provided to aid in maintaining the plunger in its retracted position under high current conditions close to, but below, the trip value. This control circuit acts to reverse the direction of current through the trip coil under these conditions such that a magnetic flux aiding that of the permanent magnet is generated. If a trip current is detected, the control circuit allows the current to flow in the normal direction through the trip coil, thus generating a magnetic…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.