Gas-Insulated Switch Speed Control at the Arc Extinction Point
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Solution Overview
Problem
Conventional methods for driving a movable contact in gas insulated devices with low arc-extinguishing performance gases result in insufficient distance between contacts for current interruption, leading to inadequate current interrupting performance.
Innovation Solution
A motor-driven switch with a drive mechanism that converts rotational motion into linear motion, controlled by a drive controller to adjust motor speed during opening and closing operations, ensuring a lower speed during the arc extinction point to enhance current interrupting capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the conventional method for driving a movable contact is applied, then the device size can be reduced, but the distance between contacts required for current interruption becomes insufficient
Solution Approach 1:
The patent applies dynamics by making the contact separation speed variable rather than constant. The drive mechanism adjusts the opening speed profile dynamically: initially high to quickly increase contact distance, then reduced at the timing corresponding to current zero-crossing to maintain the distance without excessive separation. This dynamic speed control enables sufficient current interruption while minimizing overall device size.
Solution Approach 2:
The patent changes the speed parameter during the opening operation. Specifically, the drive mechanism controls the movable contact to move at a first opening speed initially, then switches to a second opening speed (lower than the first) at a timing corresponding to current zero-crossing. This parameter change optimizes both the contact separation distance for arc extinction and the overall device compactness.
2Speed
If the movable contact is accelerated by a compression spring to increase opening speed, then the opening speed reaches maximum peak, but the current interrupting performance becomes insufficient with low arc-extinguishing performance gases
Solution Approach 1:
Instead of using a compression spring to create a peak speed profile, the patent employs a drive mechanism that dynamically controls speed throughout the opening process. The mechanism maintains higher speed initially for rapid separation, then reduces speed at the critical moment corresponding to current zero-crossing. This dynamic control ensures reliable current interruption with alternative gases while avoiding the excessive peak speeds produced by spring acceleration.
Solution Approach 2:
The patent incorporates feedback control where the drive mechanism adjusts the opening speed based on the operational phase. By detecting or estimating the current zero-crossing timing, the system feedback-controls the motor speed to switch from first opening speed to second opening speed at the appropriate moment, ensuring optimal conditions for arc extinction with low arc-extinguishing performance gases.
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 controlled motor speed during the opening operation allows for sufficient current interrupting performance, even with reduced contact separation distance, thereby supporting device miniaturization.
Implementation Method 1
a drive mechanism that converts rotational motion into linear motion
Implementation Method 2
a part of the entire moving range includes an interrupting point at which an arc current is extinguished
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3
AI summary
A switch (20) includes a fixed contact (32), a movable contact (31), a motor (22, 49) to drive the movable contact (31) via a drive mechanism (30) that converts rotational motion into linear motion, and a drive controller (21, 47) to control driving of the motor (22, 49). The drive controller (21, 47) controls a rotation speed of the motor (22, 49) such that during an opening operation of the switch (20), a moving speed of the movable contact (31) in a part of an entire moving range of the movable contact (31) is lower than a moving speed of the movable contact (31) during a closing operation of the switch (20). The part of the entire moving range includes an interrupting point at which an arc current is extinguished.