Device for short-circuit protection
AssigneeSiemens Aktiengesellschaft
InventorFritz Pohl
Life of this patent
Estimating the term…
Abstract
The current-limiting mechanism is provided in particular in order to protect electromechanical contactors from being welded by a short-circuit load. In a first step, the current-limiting mechanism closes a bridging contact of a first bridging current path in order to reduce the current load on the contactor. In a second step, its bridging function is taken over by a switching arc and by a second bridging current path, In the further course of the disconnection process, the switching arc commutates from the bridging contact onto associated running rails or arc runners and runs into an arcing chamber of the current-limiting mechanism. As a result, the short-circuit is interrupted.
Claims14
A device for short-circuit protection of an electromechanical contactor, which comprises:
- a current-limiting mechanism connected in series with an electromechanical contactor, said current-limiting mechanism comprising a contact configuration having a fixed contact, a movable contact, and an arcing chamber associated therewith;
- said current limiting mechanism defining a first bridging circuit with a bridging contact having a closing position to close said bridging contact and an opening position to open said bridging contact, a second bridging circuit, and arc runners, said bridging contact being opened under a nominal operating condition;
- said current-limiting mechanism being configured, in an event of a short circuit, to first close said bridging contact of said first bridging circuit for reducing a current load on the contactor, and to then establish a bridging function with a switching arc and via said second bridging circuit said switching arc being established when said bridging contact of said first bridging circuit is opened, and said switching arc commutates from said bridging contact onto said arc runners and runs into said arcing chamber, for interrupting the short-circuit.
In combination with an electromechanical contactor, a current-limiting device connected in series with the electromechanical contactor for protecting the electromechanical contactor against short-circuit currents, the device comprising:
- a contact configuration having a fixed contact, a movable contact, and an arcing chamber associated therewith;
- a first bridging circuit with a bridging contact having a closing position to close said bridging contact and an opening position to open said bridging contact, a second bridging circuit, and associated arc runners, said bridging contact being opened under a nominal operating condition;
- whereby, upon detecting a short-circuit current, said bridging contact of said first bridging circuit is closed for reducing a current load on the contactor, and then a bridging function of said first bridging circuit is transferred with a switching arc to said second bridging circuit, and whereby said switching arc is established when said bridging contact of said first bridging circuit is opened, and said switching arc is caused to commutate onto said arc runners and into said arcing chamber, whereupon the short-circuit is interrupted.
Dependencies are inferred from the claim text.