Gas circuit breaker

A gas circuit breaker comprising:

• a fixed arc contact extending along an operating axis;
• a moving arc contact allowed to move to a position where the moving arc contact contacts the fixed arc contact and a position where the moving arc contact is separated from the fixed arc contact by moving along the operating axis;
• a frame surrounding a circumference of the moving arc contact to form a puffer chamber around the moving arc contact;
• a nozzle having a cylindrical shape centered on the operating axis, the nozzle being fixed to the frame and projecting in a direction toward the fixed arc contact from the moving arc contact;
• and
• an arc extinction assisting portion provided on an inner surface of the nozzle and made of an ablation material, wherein
• the nozzle and the arc extinction assisting portion are provided with a fall-off preventing portion to prevent the arc extinction assisting portion from falling off the nozzle,
• the nozzle includes
• a fixed portion having a cylindrical shape centered on the operating axis and fixed to the frame, and
• a throat portion having a cylindrical shape centered on the operating axis and extending from the fixed portion toward a side where the fixed arc contact is present along the operating axis,
• the arc extinction assisting portion is provided on an inner surface of the fixed portion such that the arc extinction assisting portion extends from an end portion on a side closer to the frame to an end portion on a side closer to the throat portion, and
• the fall-off preventing portion includes
• a recessed portion formed on the nozzle and recessed in a direction along the operating axis,
• a projecting portion of the arc extinction assisting portion, the projecting portion being fitted into the recessed portion, and
• an abutting portion of the frame, the abutting portion abutting on the arc extinction assisting portion from a side where the operating axis is present.

A gas circuit breaker comprising:

• a fixed arc contact extending along an operating axis;
• a moving arc contact allowed to move to a position where the moving arc contact contacts the fixed arc contact and a position where the moving arc contact is separated from the fixed arc contact by moving along the operating axis;
• a frame surrounding a circumference of the moving arc contact to form a puffer chamber around the moving arc contact;
• a nozzle having a cylindrical shape centered on the operating axis, the nozzle being fixed to the frame and projecting in a direction toward the fixed arc contact from the moving arc contact;
• and
• an arc extinction assisting portion provided on an inner surface of the nozzle and made of an ablation material, wherein
• the nozzle and the arc extinction assisting portion are provided with a fall-off preventing portion to prevent the arc extinction assisting portion from falling off the nozzle, and
• the fall-off preventing portion includes
• an internal thread formed on the inner surface of the nozzle, and
• an external thread formed on an outer surface of the arc extinction assisting portion and meshed with the internal thread.