Switchgear Contact Drive With Nested Springs for Chattering Suppression
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Solution Overview
Problem
The existing switchgears face issues with chattering due to the increase in rigidity of laminated plates, which degrades the effectiveness of suppressing contact bounce, leading to increased contact resistance and potential fusion of contacts.
Innovation Solution
The switchgear employs an electromagnetic actuator with a power transmission unit featuring a spring member composed of two nested coils and regulating portions to manage the force and movement, reducing the impact's effect on the contacts and increasing the natural frequency, thereby suppressing chattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laminated plates are made with higher rigidity to retain the contact, then the contact retention is improved, but the effect of suppressing chattering is degraded
Solution Approach 1:
The stationary contact is divided into multiple contact portions arranged in the vertical direction, each portion independently supported by the laminated plates. This segmentation allows the contact force to be distributed across multiple points, improving retention while maintaining damping effectiveness through the layered structure.
Solution Approach 2:
The laminated plates are constructed by laminating multiple plates on each other, creating a nested layered structure. This nesting provides both the rigidity needed for contact retention and the inter-layer damping effect to suppress chattering, resolving the contradiction between strength and vibration suppression.
2Reliability
If the natural frequency is increased to suppress chattering, then the chattering suppression is improved, but the pressing force fluctuation may increase
Solution Approach 1:
The movable contact is designed to move between opened and closed positions with dynamic control of the pressing force. The control unit adjusts the pressing force based on the operational state, maintaining stability while allowing the natural frequency to be increased for chattering suppression.
Solution Approach 2:
The control unit dynamically changes the pressing force parameter based on the switchgear's operational state. By adjusting this parameter, the system can maintain stable contact pressure while operating at higher natural frequencies to suppress chattering.
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
This configuration effectively reduces the chattering by minimizing the fluctuation of pressing force and increasing the natural frequency, resulting in improved contact stability and reduced wear on the contacts.
Implementation Method 1
a spring member (55) provided between the drive unit-side spring bearing portion (51) and the contact-side spring bearing portion (52) and configured to push the drive unit-side spring bearing portion (51) and the contact-side spring bearing portion (52) in directions in which the drive unit-side spring bearing portion (51) and the contact-side spring bearing portion (52) are separated from each other
Implementation Method 2
an electromagnetic actuator (drive unit) (4) configured to generate power for shifting the movable contact (3)
Data Source
Figure 1~2
Figure 3(a)~3(f)
Figure 4~5
AI summary
Provided is a switchgear, including: a stationary contact; a movable contact, which is configured to be shifted between a closed position and an opened position; an electromagnetic actuator, which is configured to generate power for shifting the movable contact, the electromagnetic actuator including a stator and a movable element; and a power transmission unit, which is configured to shift the movable contact through transmission of the power of the electromagnetic actuator, and to press the movable contact against the stationary contact when the movable contact is located at the closed position, the power transmission unit including: a drive unit-side spring bearing portion, which is configured to be shifted together with the movable element; a contact-side spring bearing portion, which is provided so as to be opposed to the drive unit-side spring bearing portion, and is configured to be shifted together with the movable contact; and a spring member, which is provided between the drive unit-side spring bearing portion and the contact-side spring bearing portion, the spring member including: an outer spring; and an inner spring, which is connected in parallel to the outer spring, and is arranged so as to be contracted by the same amount as the outer spring during a period in which the movable contact is shifted from a state of being located at the opened position to a state of being located at a terminal end of switch-on action.