Electromagnetic Actuator Structure to Suppress Switch Chattering
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Solution Overview
Problem
Existing high-speed electromagnetic actuators for switchgear suffer from complex structures, increased power supply size, and significant rebound and chattering during high-speed operations, particularly during closing operations.
Innovation Solution
A simplified electromagnetic actuator design utilizing a repulsive plate, a movable core, and a disk spring, where a single coil generates electromagnetic forces to achieve high-speed operation with reduced rebound and chattering by adjusting the distance between the repulsive plate and the coil, and utilizing the elastic force of the disk spring to stabilize the movable shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil is used to generate electromagnetic forces for high-speed operation, then the device complexity and power supply size are reduced, but the control precision and reliability of high-speed operation may be insufficient
Solution Approach 1:
The patent divides the electromagnetic actuator into two independent coils (first coil and second coil) with distinct functions: the first coil generates electromagnetic force for high-speed movement, while the second coil provides controlled electromagnetic braking. This segmentation allows each coil to be optimized for its specific function, ensuring reliable high-speed operation while maintaining relatively simple overall structure.
Solution Approach 2:
The patent introduces a non-magnetic plate as an intermediary component between the coils and the movable core. This plate serves as a mediator that transmits electromagnetic forces from the coils to the movable core while preventing direct magnetic interaction, thereby enabling independent control of the two coils and improving the reliability of high-speed operation.
2Speed
If electromagnetic force is used to achieve high-speed operation, then the operating speed is improved, but rebound and chattering occur during closing operations
Solution Approach 1:
The patent applies preliminary anti-action by using the second coil to generate an opposing electromagnetic force that counteracts the rebound and chattering caused by the first coil's electromagnetic force. The second coil is activated in advance or simultaneously with the first coil to prevent harmful vibrations before they fully develop, thereby enabling high-speed operation without excessive rebound.
Solution Approach 2:
The patent employs periodic action by controlling the timing and duration of current pulses to both coils. The first coil receives a pulse for high-speed actuation, while the second coil receives a subsequently timed pulse to provide braking action. This periodic control pattern eliminates continuous electromagnetic force application, thereby reducing rebound and chattering while maintaining high operating speed.
3Speed
If the distance between the repulsive plate and the coil is decreased to increase electromagnetic force, then the operating speed is improved, but the risk of contact and damage increases
Solution Approach 1:
The non-magnetic plate serves as a protective intermediary that is positioned closer to the coil than the movable core. This plate can be made of non-magnetic material and is designed to prevent direct contact between the movable core and the coil, thereby allowing the distance to be reduced for higher electromagnetic force while eliminating the risk of contact damage.
Solution Approach 2:
The patent changes the material parameter of the plate between the coil and movable core to non-magnetic material. This parameter change allows the plate to be positioned closer to the coil without creating magnetic short circuits or contact damage, thereby enabling reduced distance for higher operating speed while maintaining safety.
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 design enables high-speed operation with reduced size and complexity, effectively suppressing chattering and rebound, thus enhancing the reliability and efficiency of the switchgear.
Implementation Method 1
when a first coil is energized, operation is performed in the opening direction by an electromagnetic force generated on a repulsive plate
Implementation Method 2
an attracting force from a permanent magnet of the retention mechanism is canceled out so that the retention is released
Implementation Method 3
eddy current is generated in a repulsive plate located close to the first coil. Then, a magnetic field of the first coil and a magnetic field due to the eddy current repel each other
Implementation Method 4
by using a spring with a varying spring constant from closing to electrode opening as a loading spring, spring load in the opened electrode state is made smaller than a spring load in the closed electrode state
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An object is to provide an electromagnetic actuator (3) that enables high-speed operation of a switch (1) with a simple structure, the switch (1) that enables suppression of chattering caused due to high-speed operation, and a switchgear (51) having the switch (1). The electromagnetic actuator (3) includes a repulsive plate (21) and a movable core (22) connected to a movable shaft (15) so as to be opposed to each other with a coil (22) interposed therebetween. In an opened state, the distance between the repulsive plate (21) and the coil (22) is smaller than the distance between the movable core (23) and the coil (22). A disk spring (30) is connected to the movable shaft (15), to fix the movable shaft (15). When the coil (22) is energized, the movable shaft (15) moves to close electrodes, the distance between the movable core (23) and the coil (22) becomes small, and the disk spring (30) is reversed to press the movable shaft (15) in the closing direction.