Stepping Switch Guide Device Prevents Contact Misalignment
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Solution Overview
Problem
Misalignment of moving contacts in vacuum interrupters of tap changers reduces the dielectric strength, limiting the maximum current that can be switched and requiring oversized components.
Innovation Solution
A guide device that moves with the plunger and is supported on the housing, preventing tilting and misalignment, and also protects external bellows from mechanical damage, ensuring reliable guidance and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no guide device is used, then the structure is simpler, but the movable contact misaligns relative to the fixed contact, reducing dielectric strength
Solution Approach 1:
A guide device is introduced as an intermediary component between the actuating device and the movable contact. The guide device includes a guide section that rests against the housing and guides the plunger and movable contact during actuation, preventing misalignment and offset of the movable contact relative to the fixed contact.
Solution Approach 2:
The guide device is divided into distinct functional sections: a guide section that rests against the housing to provide guidance, and a protection section that surrounds the bellows. This segmentation allows each part to perform its specific function efficiently while maintaining overall structural integrity.
2Reliability
If the vacuum interrupter is oversized to compensate for misalignment, then dielectric strength is maintained, but the device size and cost increase
Solution Approach 1:
The guide device prevents misalignment before it can occur during the actuation process. By providing continuous guidance from the housing during the entire movement of the plunger and movable contact, the system eliminates the need for oversizing the vacuum interrupter to compensate for potential alignment issues.
3Reliability
If the guide device is inside the housing, then guidance is provided, but the bellows are exposed to mechanical damage
Solution Approach 1:
The guide device performs multiple functions: the guide section provides guidance for the plunger and movable contact, while the protection section surrounds and protects the external bellows from mechanical damage. This multi-functional design eliminates the need for separate protection components.
Solution Approach 2:
The protection section of the guide device is arranged to surround the external bellows, creating a nested structure where the guide device encloses the bellows. This nesting provides mechanical protection without interfering with the actuation process or requiring additional external protection structures.
Data Source
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AI summary
The invention relates to a switch element for a step switch comprising a vacuum interrupter (V), an actuating device, and a guide device (F). The vacuum interrupter (V) according to the invention comprises a movable contact (K1), a plunger (ST) connected to the movable contact (K1), and a housing. The movable contact (K1) is arranged in the interior of the housing. The actuating device is designed to actuate the plunger (ST). The guide device (F) is arranged outside the housing and is fixed to the actuating device. The guide device (F) encloses the housing at least in part. At least one partial region of the guide device (F) contacts the housing.