Electromagnetic Actuator Control for Switching Device
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Solution Overview
Problem
Electromagnetically actuated switching devices for low or medium voltage applications face issues with high kinetic energy storage leading to contact overrun and bouncing, increased mechanical stresses, vibrations, and frequent maintenance needs, resulting in reduced safety, reliability, and higher operational costs.
Innovation Solution
A switching device with an electromagnetic actuator and sensor-controlled power supply that stops excitation current before the movable plunger reaches its stop position, utilizing a kinematic chain and power storage stage to manage energy and reduce mechanical stress, incorporating control means to determine the optimal cessation of excitation current based on sensing signals and predefined conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the excitation current is supplied for a predetermined time to actuate the movable plunger, then the switching operation is completed, but the movable plunger stores high kinetic energy causing overrun and bouncing of contacts
Solution Approach 1:
The patent employs sensor means to detect the actual position of the movable plunger during its actuation and feeds this information back to the control means. The control means uses this feedback to dynamically adjust the duration of excitation current supply, stopping the current precisely when the plunger reaches the desired position rather than using a fixed predetermined time. This feedback mechanism prevents over-travel and kinetic energy accumulation that causes contact bouncing.
Solution Approach 2:
The control means determines the optimal time to stop supplying excitation current before the movable plunger actually reaches the stop position. By calculating and acting in advance based on the plunger's motion characteristics and sensor feedback, the system prevents the plunger from acquiring excessive kinetic energy that would otherwise cause overrun and contact bouncing.
2Speed
If the movable plunger is actuated with high kinetic energy to ensure rapid switching, then the switching speed is improved, but mechanical stresses and vibrations increase leading to rapid wear
Solution Approach 1:
Sensor means continuously monitor the movable plunger's position and velocity, providing real-time feedback to the control means. This feedback enables the control means to adjust the excitation current timing dynamically, ensuring the plunger achieves sufficient speed for rapid switching while preventing excessive kinetic energy that would cause mechanical stresses, vibrations, and wear on the actuation chain components.
3Extent of automation
If traditional electromagnetic actuation is used to actuate the mobile contact, then the switching operation is automated, but frequent maintenance interventions are needed due to mechanical stresses and vibrations
Solution Approach 1:
The patent introduces sensor means that provide real-time feedback on the movable plunger's position and the actuation chain's state. The control means uses this feedback to precisely control the excitation current duration, reducing mechanical stresses and vibrations on the actuation chain. This feedback-controlled approach maintains automation while significantly reducing wear and maintenance frequency by preventing excessive kinetic energy transmission to mechanical components.
Solution Approach 2:
The control means automatically adjusts the excitation current timing based on sensor feedback without requiring manual intervention. The system self-regulates to optimize the switching operation, reducing mechanical wear and maintenance needs while maintaining full automation of the switching process.
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 solution reduces mechanical stresses and vibrations, decreases wear, minimizes maintenance requirements, enhances safety and reliability, and lowers operational costs by controlling the switching operation to prevent contact overrun and maintain efficient energy use.
Implementation Method 1
an electromagnetic actuator for actuating the mobile contact, which generally comprises a magnetic circuit provided with an excitation coil operatively associated to a movable plunger
Implementation Method 2
The magnetic field generated by the excitation current circulating in the excitation coil operates the movable plunger that can be reversibly moved between two operative positions
Data Source
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AI summary
A switching device (1) comprising: - at least a movable contact (11) and a fixed contact (12) that are adapted to be coupled or uncoupled during a switching operation of said switching device; - an electromagnetic actuator (13) comprising an excitation coil (131), in which an excitation current (IE) circulates during a switching operation, and a movable plunger (132), which is operatively coupled to said movable contact through a kinematic chain (14), said movable plunger being operated between a start position (P1) and a stop position (P2) during a during a switching operation; - power supply means (16) that supply said excitation current to said excitation coil during a switching operation of said switching device; - sensor means (15) that generate sensing signals indicative of the intensity of said excitation current; - control means (17) for controlling the switching operations of said switching device, said control means receiving the sensing signals generated by said sensor means. During the execution of a switching operation, said control means: - send a first control signal to said power supply means to start with the supply of said excitation current from a first instant (T1) onwards; - determine, on the base of the information provided by said sensing signals, a second instant (T2), at which said power supply means have to stop with the supply of said excitation current, said second instant occurring before said movable plunger has reached said stop position (P2) during the movement from said start position (P1) towards said stop position (P2); - send a second control signal to said power supply means to stop with the supply of said excitation current from said second instant (T2) and until said movable plunger reaches said stop position.