Electromechanical Switch Actuation Using Contact-Rubbing Coil Pulses
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Solution Overview
Problem
Existing methods for actuating electromechanical switching elements, such as relays, fail to effectively prevent errors like contact failure or non-interruption of current flow due to mechanical interlocking, oxide layers, or welding, which are not adequately addressed by existing correction methods.
Innovation Solution
A method involving pulsing the coil current between predefined maximum and minimum values during the switch-on or switch-off process within an overtravel range, causing the armature to move and rub the contacts without detachment, using a microcontroller to detect and correct faulty states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil current is pulsed between maximum and minimum values within the overtravel range during switch-off or switch-on process, then the contacts are rubbed against each other without detachment to prevent errors, but the complexity of the actuation control increases
Solution Approach 1:
The patent applies periodic pulsing of the coil current during the switch-off or switch-on process. The current is pulsed repeatedly at a predefined point in time within the overtravel range, creating periodic mechanical motion of the armature that rubs the contacts together. This periodic action eliminates contact errors through repeated rubbing without requiring complete contact detachment and reconnection, thus improving reliability while avoiding the complexity of full switching cycles.
Solution Approach 2:
The patent implements preliminary action by detecting a predefined condition (such as contact resistance exceeding a threshold or abnormal current characteristics) before complete contact failure occurs. When this condition is detected during the switch-off or switch-on process, the pulsing actuation is immediately triggered to rub the contacts and prevent error development. This preliminary intervention prevents contact welding or complete failure, improving reliability while avoiding the need for complex post-failure correction mechanisms.
2Reliability
If the armature is moved within the overtravel range to rub the contacts, then contact errors are corrected, but the duration of the switching process increases
Solution Approach 1:
The patent uses periodic pulsing of the coil current during the switching process rather than extending the full switching duration. The pulsing occurs repeatedly at a predefined point within the overtravel range, creating multiple rubbing actions within the existing switching time window. This approach corrects contact errors through repeated small-amplitude motions rather than requiring a single extended switching cycle, thus maintaining fast switching while improving contact reliability.
Solution Approach 2:
The patent ensures continuity of useful action by integrating the contact rubbing function into the existing switch-off or switch-on process. The pulsing actuation occurs continuously during the overtravel phase of the normal switching operation, combining the primary switching function with the secondary contact maintenance function. This eliminates the need for separate correction cycles, maintaining fast switching response while continuously rubbing the contacts to prevent errors.
3Reliability
If the coil current oscillates between maximum and minimum values, then the armature moves to rub the contacts, but the energy consumption increases
Solution Approach 1:
The patent applies periodic pulsing of the coil current rather than continuous current flow. The current is switched between maximum and minimum values at specific intervals during the overtravel phase, creating the necessary armature motion for contact rubbing only when needed. This periodic actuation reduces overall energy consumption compared to maintaining continuous current, while still achieving the reliability improvement through repeated contact rubbing during the pulsing cycles.
Solution Approach 2:
The patent uses partial action by applying coil current pulsing only during the overtravel phase of the switching process, rather than during the entire switching cycle. The minimum current value is set at the point where the armature begins to detach, and pulsing occurs only within this specific range. This partial application of energy achieves the contact rubbing function with minimal additional energy consumption, improving reliability without excessive energy use.
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
Prevents contact detachment and maintains conductivity by repeatedly rubbing the contacts, reducing failure rates and ensuring continuous system operation without interruptions.
Implementation Method 1
a coil with an iron core... the coil current flowing into the coil oscillates between a predefined maximum value and a minimum value so that the armature moves within the overtravel range
Data Source
AI summary
A method for actuating an electromechanical switching element including a plurality of contacts, a coil with an iron core, and an armature includes: in the event that a predefined condition is fulfilled, in a switch-off process pulsing on and off or in the switch-on process pulsing off and on of the switching element is carried out repeatedly at a predefined time within an overtravel range such that a coil current flowing into the coil oscillates between a predefined maximum value and a minimum value so that the armature moves within the overtravel range and the plurality of contacts thereby rub against each other without becoming detached from each other. The minimum value is defined as a current value at a time at which the armature begins to detach from the iron core.