Switching Apparatus Arc Wear Reduction via Energy Buffer
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Solution Overview
Problem
Existing switching devices for controlling electric motors in industrial automation face limitations in the number of switching cycles due to wear caused by switch-off arcs during emergency shutdowns, and they do not ensure safe and controlled switching off of motors.
Innovation Solution
A switching device with a control unit, energy store, and measuring device that buffers energy supply and monitors voltage levels, allowing for controlled switching off by switching semiconductor and electromechanical switches in a manner that prevents arcing and extends the device's operational lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply voltage is switched off to shut down the motor, then the motor is reliably switched off, but the switches experience heavy wear due to switch-off arcs
Solution Approach 1:
The energy store (capacitor) is pre-charged during normal operation to provide energy for controlled switching off. When shutdown is required, this stored energy enables the semiconductor switch to remain conductive longer, allowing the electromechanical switch to open without arcing, thus preventing wear while ensuring reliable motor shutdown.
Solution Approach 2:
The semiconductor switch acts as an intermediary between the control signal and the electromechanical switch. By controlling the semiconductor switch to remain conductive during the opening of the electromechanical switch, it prevents arc formation at the electromechanical contacts, thereby extending their service life while maintaining reliable motor shutdown.
2Reliability
If the energy supply is monitored and controlled, then safe switching off is ensured, but the device complexity increases
Solution Approach 1:
A monitoring device detects the energy supply status and provides feedback to the control unit. When energy supply falls into a critical range, the control unit responds by activating the controlled switching sequence using the energy store, ensuring reliable shutdown without requiring complex continuous control systems.
Solution Approach 2:
The energy store automatically provides the necessary energy for controlled switching when the monitoring device detects critical energy supply conditions. This self-service mechanism reduces the burden on the control system, maintaining reliability while minimizing the complexity of active monitoring and control components.
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 enables increased switching cycles with reduced wear on switches, ensuring safe and controlled shutdowns of electric motors, minimizing mechanical switch wear and maintaining a constant voltage level during shutdown processes.
Implementation Method 1
the switching device comprises an energy store and a measuring device connected to the control unit, the energy store between the supply connection and the power pack is interposed, so that by means of the energy store, an energy supply of the switching device via the supply connection is buffered internally
Implementation Method 2
a parallel connection of a second electromechanical switch with a semiconductor switch connected in series with the first switch. The control unit can output a switching signal for the first switch, the second switch and the semiconductor switch
Implementation Method 3
The first and second switches are in particular normally open contacts, which are kept in the closed switching state when a switching signal from the control unit is present. If the switching signal is switched off by the first or second switch, the switch automatically assumes the open state due to a restoring force (e.g. a spring force which acts on a contact of the respective switch)
Implementation Method 4
the control unit using the measuring device monitoring the energy supply of the switching device via the supply connection in the area between the supply connection and the power pack
Data Source
Figure 1
AI summary
The invention relates to a switching device (1) with a control apparatus (2), a supply connection (7), a power supply (19) and a first flow path of current (15) which comprises a first electromechanical switch (11) and a parallel circuit of a second electromechanical switch (13) with a semiconductor switch (12) connected in series to the first switch (11). In order to provide a switching device (1) which has an increased number of cycles, it is proposed that the switching device (1) comprises an energy store (6) and a measuring device (8) connected to the control apparatus (2), wherein the energy store (6) is connected in series between the supply connection (7) and the power supply (19), wherein the control apparatus (2) can monitor the energy supply of the switching device in the area between the supply connection (7) and the power supply (19) taking place via the supply connection (7) by means of the measuring device (8), the control apparatus (2) being designed such that, if the energy supply monitored by means of the measuring device (8) falls into a critical range, and using the energy from the energy store (6): said control apparatus (2) in a first step connects the semiconductor switch (12) in an electrically conductive manner and then opens the second switch (13); and after the first step, switches the semiconductor switch (12) to an electrically non-conductive state and then opens the first switch (11) in a second step.