Electromagnetic actuators
AssigneeFki PLC
InventorsStephen Ernest Lane, Martin Snell
Life of this patent
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Abstract
An electromagnetic actuator for a circuit breaker having a pair of relatively moveable contacts is disclosed. The actuator includes primary actuator coupled to at least one of the contacts by a link mechanism operable to provide closing and holding forces to the contacts of the circuit breaker and a secondary, faster acting actuator which, on tripping thereof, provides sufficient force to at least initiate opening of the contacts by the configuration of the link mechanism. The secondary actuator includes a stored energy latch which has a permanent magnet flux circuit for providing a holding force and a coil connected to receive a trigger signal to overcome the permanent magnet flux to trip the latch.
Claims21
A circuit breaker comprising:
- a pair of relatively moveable contacts;
- a primary actuator coupled to at least one of said contacts by a link mechanism and providing closing and holding forces to the contacts of the circuit breaker;
- and
- a secondary, faster acting, actuator which, on tripping thereof, provides sufficient force to at least initiate opening of the contacts by modifying the configuration of said link mechanism;
- wherein the secondary actuator comprises a stored energy latch which includes a permanent magnet flux circuit for providing a holding force and a coil connected to receive a trigger signal to overcome said permanent magnet flux to trip said latch.
A circuit breaker according to claim 7 in which the secondary actuator mechanism accelerates the movement of the drive shaft from a first position to a second position by absorbing a snatch gap in the primary actuator mechanism substantially prior to movement of the primary actuator mechanism during an opening stroke.
An actuator for a circuit breaker comprising:
- a drive shaft system for coupling at one end to a moveable contact of a circuit breaker;
- a primary actuator mechanism coupled to another end of the drive shaft;
- a secondary actuator mechanism operable to, upon receiving a trigger signal, modify the configuration of the drive shaft;
- wherein the drive shaft system further comprises:
- an actuator rod coupled to an armature in said primary actuator mechanism which actuator mechanism is operable to drive the actuator rod in a direction substantially parallel to its longitudinal axis, and
- link mechanism, coupled at a first end to the actuator rod and having a second end for coupling to the moveable contact of the circuit breaker, the link mechanism having first and second link members each having a respective first angular relationship with said actuator rod in a first position, and each having a respective second angular relationship with said actuator rod in a second position, wherein the change in said angular relationships modifies the effective length of the link mechanism between the primary actuator mechanism and said moveable contact,
- the primary and secondary actuators between them being capable of imparting a linear displacement of said link mechanism for effecting movement of the moveable contact.
Dependencies are inferred from the claim text.