Magnetically Actuated Tap Changer Switch Without Vacuum Interrupters
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Solution Overview
Problem
On-load tap changers with vacuum interrupters face challenges such as high actuation force dependency on external pressure and high costs, particularly in transformers with small load currents and step voltages, where the advantageous properties of vacuum interrupters are not necessary.
Innovation Solution
A compact and economical switching means for on-load tap changers featuring fixed and moving contacts with external attraction elements, allowing actuation independent of external pressure, replacing costly vacuum interrupters with a robust and sealed design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum interrupters are used in on-load tap changers, then contact wear is reduced and switching performance is improved, but actuation force becomes heavily dependent on external pressure and cost increases
Solution Approach 1:
The patent extracts the moving contact from the vacuum environment by providing a opening in the vacuum interrupter envelope that allows the moving contact to extend outward. This enables the moving contact to be actuated by external magnetic attraction elements while maintaining the vacuum seal for the fixed contacts, thereby reducing actuation force dependency on external pressure while preserving contact wear resistance
Solution Approach 2:
The patent introduces a magnetic coupling mechanism as an intermediary between the external actuation system and the internal vacuum environment. External magnetic attraction elements interact with the moving contact through the opening without requiring direct mechanical connection, allowing actuation independent of external pressure while maintaining vacuum integrity
2Reliability
If vacuum interrupters are used in on-load tap changers, then switching performance is improved, but cost increases significantly
Solution Approach 1:
The patent replaces the expensive vacuum interrupter structure with a more economical design that uses a sealed envelope with an opening for the moving contact. This allows the use of simpler, less costly materials and manufacturing processes while maintaining the essential vacuum protection for the fixed contacts and enabling external actuation of the moving contact
3Reliability
If a sealed design is used for the switch, then reliability is improved, but assembly complexity increases
Solution Approach 1:
The patent segments the switch into distinct components: a sealed envelope containing the fixed contacts and vacuum environment, and an external moving contact assembly that can be independently manufactured and then assembled. The opening in the envelope is designed to receive the moving contact in a straightforward manner, reducing assembly complexity while maintaining sealed integrity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective, reliable, and simplified on-load tap changer with reduced assembly complexity and actuation force dependency on external pressure, suitable for transformers with small load currents and step voltages, enhancing safety and ease of assembly.
Implementation Method 1
The moving contact is movable from a first position into a second position via the first attraction element and a second attraction element, which is arranged outside the switch
Data Source
AI summary
A switch can be used for an on-load tap changer. The switch includes: fixed contacts, including a first fixed contact and a second fixed contact; and a moving contact with a first attraction element. The moving contact is movable from a first position into a second position via the first attraction element and a second attraction element, which is arranged outside the switch. The moving contact is configured such that, in the first position, the moving contact contacts neither or only one of the fixed contacts and, in the second position, the moving contact contacts both of the fixed contacts.