Abstract: A make break switchgear includes a first breaking lever receiving a torque in a counterclockwise direction, a second breaking lever connected through a linkage to the first breaking lever, and a making lever receiving a torque in a clockwise direction. These elements are supported by a main shaft and are rotatable. When a circuit is completely opened by the switchgear, a guide guiding a rotor on an arched surface is engaged with a first releasing latch. It is unnecessary to wait for engagement between the first releasing latch and the guide after the circuit is closed for opening the switchgear, and a subsequent opening can be immediately started. Therefore, it is possible to reduce the time from the closing of a make break contact to starting of the next opening.

Abstract: A first breaking lever 52, applied with torque in a counterclockwise direction, a second breaking lever 55, connected thereto through a linkage 47, and a making lever 76, applied with a torque in a clockwise direction, are supported by a main shaft 51 so as to be rotatable, and when the circuit is completely opened, a guide 62 for guiding a rotor 59 on an arch surface 62a is engaged with a first releasing latch 69. It is unnecessary to wait an engagement between the first releasing latch 69 and the guide 62 after the circuit is closed, and a next operation of opening the circuit can be immediately started. Therefore, it is possible to reduce a time from a close of the make break contact to a next start of the operation of opening the circuit.

Abstract: A making operation preventing device 130 has a releasing trigger 19 for retaining, via a releasing latch 18, a breaking lever 36 to which a torque in a counterclockwise direction is applied by an opening torsion bar 34; a releasing electromagnet 20 for opening an on-off contact 10 by releasing the engagement between the releasing trigger 19 and the releasing latch 18 to rotate the breaking lever 36 in a counterclockwise direction; a cam 3 rotated as one body with a gear 40 connected via a link 41 to a making lever 37 to which a torque in a counterclockwise direction is applied by a closing torsion bar 35; a making trigger 15 which retains a second pin 13 attached to the cam 3 via a making latch 14 and maintains the closing torsion bar 35 in a prestressing state; a releasing electromagnet 16 for driving a trigger lever 16d in a right direction to release the engagement between the making latch 14 and the making trigger 15, and an interlocking electromagnet for rotating the trigger lever 16d in a counterclockwi

Abstract: A device for controlling a breaker comprising a weight (48) provided in the vicinity of a releasing trigger (19) and an auxiliary spring (50 )for urging the weight (48) so that the weight (48)is in contact with the releasing trigger (19). An equivalent mass of the weight (48)is about one-third of an equivalent mass of the releasing trigger. When the releasing trigger (19)is in contact with a pin (45) of a releasing latch (18), the weight (48)rebounds but the releasing trigger (19)is settled without rebounding. By such a structure, the rebound of releasing latch and the releasing trigger is prevented when these are engaged, whereby a time for closing a circuit is shortened.