Off-circuit tap-changer for transformation after force discharging of moving contact

Abstract

The invention relates to an off-circuit tap-changer for transformation after force discharging of a moving contact. The off-circuit tap-changer mainly comprises a main shaft, a gear indicating rod, a shielding cover, a gear system, a grooved pulley system, a contact support, a moving contact system, a fixed contact system and a cam system. The number of moving contact groups ranges from one to three. The off-circuit tap-changer can be used for single-phase, two-phase and three-phase loads. The off-circuit tap-changer for transformation after the force discharging of the moving contact mainly breaks through the fixed thinking mode of the structure that the contacts of a former off-circuit tap-changer directly overcomes a resistance dead point to achieve gear shifting, a brand new ground-breaking mode is adopted, the advantage that an inner grooved pulley mechanism is small in occupied space is utilized ingeniously, perfect cooperation of a gear mechanism and a cam mechanism is further utilized, it can be completely guaranteed that the moving contacts make reliable and stable contact with the fixed contacts under a normal work state of the off-circuit tap-changer, and gear shifting can be achieved easily when the off-circuit tap-changer carries out gear shifting.

Description

technical field [0001] The invention belongs to the field of off-excitation tap-changers, in particular to an off-excitation tap-changer for switching after a moving contact is unloaded. Background technique [0002] There are three kinds of moving contact structures of non-excitation drum type tap-changers on the market: wedge-shaped moving contact mechanism, rolling ring type moving contact mechanism, arc surface (or curved surface) sliding type moving contact mechanism. [0003] The wedge-shaped moving contact mechanism has been used for many years and is a product designed in the 1980s. The obvious disadvantage of this structure is that the shift positioning is not simple, and the operator needs to turn the shift handle to make the crankshaft rotate 370°, and then turn back 10° The corner is in the next gear, and there is no hand feeling, so the operator is often confused when shifting gears; and the shifting gear cannot be reversed. If there is an overshift and...

AI Technical Summary

Problems solved by technology

[0003] The wedge-shaped moving contact mechanism has been used for many years and is a product designed in the 1980s. The obvious disadvantage of this structure is that the shift positioning is not simple, and the operator needs to turn the shift handle to make the crankshaft rotate 370°, and then turn back 10° The corner is in the next gear, and there is no hand feeling, so the operator is often confused when shifting gears; and the shifting gear cannot be reversed. If there is an overshift and a callback is required, the operator has to continue to rotate in the same direction to the required callback. position, so the operation is inconvenient; in order to ensure the contact pressure of the contact, increase the pressure of the contact spring of the moving contact, thereby increasing the rotational torque of the switch, especially for two-phase, three-phase or high-current switches, the rotational torque is even greater, It is enough to damage the switch mechanism, so the structure cannot be used for high-current switches and two-phase and three-phase switches

[0004] Pure rolling circular ring moving contact mechanism, this structure is limited by the structure, the smaller the moving contact ring, the torque will increase; the larger the moving contact ring will shorten the insulation distance with the adjacent contacts, so The moving contact ring cannot be made too large, which will lead to a large switching torque. Therefore, the obvious disadvantage of this structure is that the switching torque is large and the ring contacts are easily deformed; moreover, when the contacts of this structure are in contact, the spring force is the smallest. , but the spring pressure is the largest when shifting gears. This is a phenomenon that should be avoided when making switches.

[0005] The arc surface (or curved surface) sliding moving contact mechanism, the obvious disadvantage of this structure is that the torque is too large. This is due to structural limitations. The curvature of the arc is small, the torque increases, and the width of the contact increases when the curvature of the arc is large. Large, it will shorten the insulation distance with the adjacent contacts, so the width of the moving contact cannot be made too large; moreover, when the contacts of this structure are in contact, the spring force is the smallest, but when shifting gears, it is the spring pressure The biggest, this is also the phenomenon that you should try your best to avoid when making switches

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