Electro-magnetic device

An electro-magnetically operable device for a circuit breaker, the device including

• a coil which defines a cavity;
• a first plunger arranged in the cavity, the first plunger being displaceable within the cavity in a damped manner between a first, normal position and a second position;
• a first urging means for urging the first plunger from its second position towards its first position;
• a second plunger arranged in the cavity, adjacent the first plunger, the second plunger being displaceable within the cavity between a first, normal position and a second position;
• a second urging means for urging the second plunger from its second position towards its first position;
• a magnetic path defining means arranged about at least a part of the coil, the magnetic path defining means including a pole piece, the pole piece and the plungers being arranged such that a gap between the first plunger, when in its normal position, and the pole piece is less than a gap between the second plunger, when in its normal position, and the pole piece, with the second position of each plunger being closer to the pole piece than the first, normal position of each plunger;
• and
• an end of the second plunger, remote from the pole piece, carrying a link mechanically linking the second plunger to a moving contact carrier of the circuit breaker, said link being a lost-motion link such that the moving contact carrier can move independently of said second plunger, and said second plunger can, to a predetermined extent, move independently of the moving contact carrier.