Circuit breaker including positive temperature coefficient resistivity elements having a reduced tolerance
US5933311A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 1998 |
| Grant date | Aug 3, 1999 |
| Priority date | — |
| Expiry date | Apr 2, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/33
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit breaker including a switch having an open and a closed position connected to a line of the circuit breaker. A first actuating device, actuated by a first activating signal, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. A positive temperature coefficient resistivity element (PTC element) is tripped at least once wherein the tolerance of the PTC element is reduced and the PTC element is connected to the first actuating device for providing the first activating signal. In another embodiment of the present invention, a second actuating device, actuated by a second activating signal provided by the circuit breaker current, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. In another embodiment of the present invention, a plurality of PTC elements are tested to determine a tolerance value for each of the PTC elements and at least two of the PTC elements are matched wherein, when the at least two PTC elements are connected in parallel, the combined tolerance is red…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.