Contactor Magnetic Force Control to Prevent Short-Circuit Welding
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Solution Overview
Problem
Contactors face a challenge in maintaining a long service life due to the difference between mechanical and electrical life, where short-circuit currents cause electric repulsion forces leading to contact welding and potential failure.
Innovation Solution
The contactor design includes an electromagnetic component, a static contact, a movable contact, a first elastic part, a driving part, a sensor, and a controller. The controller adjusts the magnetic field generated by the electromagnetic component to counteract the electric repulsion force, preventing the movable contact from welding with the static contact during short-circuit conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the contactor is designed with simple structure and low cost, then manufacturing ease is improved, but electrical life deteriorates due to contact welding under short-circuit conditions
Solution Approach 1:
The patent applies dynamics by making the electromagnetic driving force adjustable rather than fixed. The controller dynamically modifies the magnetic field strength based on real-time monitoring of contact force and current conditions, allowing the system to adapt between normal operation and short-circuit protection modes, thereby extending electrical life without compromising manufacturing simplicity
Solution Approach 2:
The patent implements feedback through sensors that continuously monitor the contact force and current flowing through the contacts. This feedback loop enables the controller to detect short-circuit conditions and adjust the electromagnetic driving force accordingly, preventing contact welding and extending electrical life while maintaining a simple and cost-effective design
2Reliability
If the electromagnetic driving force is increased to ensure reliable contact closure, then contact reliability is improved, but contact welding occurs under short-circuit conditions due to excessive force
Solution Approach 1:
The patent makes the electromagnetic driving force dynamic rather than static. During normal operation, the full driving force ensures reliable contact closure. During short-circuit conditions, the controller reduces the driving force to prevent contact welding, thus resolving the contradiction between contact reliability and harmful effects
Solution Approach 2:
The patent changes the parameter of electromagnetic driving force based on operating conditions. By adjusting the magnetic field strength and controlling the coil current, the system optimizes the driving force for normal operation and reduces it during short-circuits, preventing contact welding while maintaining contact reliability
3Productivity
If the contactor operates frequently to meet productivity requirements, then productivity is improved, but electrical life decreases due to accumulated wear and contact welding
Solution Approach 1:
The patent uses feedback from sensors monitoring contact force and current to detect short-circuit conditions during frequent operations. The controller responds by adjusting the electromagnetic driving force to prevent contact welding, enabling high-frequency operation without compromising electrical life
Solution Approach 2:
The contactor system performs self-protection by automatically detecting short-circuit conditions through its sensors and adjusting its own electromagnetic driving force to prevent contact welding, allowing frequent operations to be performed safely without external intervention
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 effectively extends the electrical life of the contactor by preventing contact welding during short-circuit events, thereby enhancing the reliability and performance of the contactor beyond standard specifications.
Implementation Method 1
a driving part configured to produce an electromagnetic driving force through a magnetic field generated by an electromagnetic component
Implementation Method 2
a first elastic part configured to generate an elastic force supporting the movable component
Implementation Method 3
a sensor configured to detect the displacement of the driving part based on the electric repulsion force generated by the current flowing through the movable contact and the static contact
Data Source
Figure 1~2A
Figure 2B~3A
Figure 3B~3C
AI summary
A contactor and a control method thereof are disclosed, the contactor comprising: an electromagnetic component; a static contact; a movable component comprising a connected movable contact, a first elastic part configured to generate an elastic force supporting the movable component and a driving part configured to produce an electromagnetic driving force through a magnetic field generated by the electromagnetic component; a sensor; and a controller configured to: control the movable contact of the movable component and the static contact to be closed, in response to the sensor detecting that the driving part is displaced based on the electric repulsion force generated by the current flowing through the movable contact and the static contact, control the electromagnetic component to adjust the generated magnetic field to reduce the electromagnetic driving force produced by the driving part based on the generated magnetic field in the opposite direction to the electric repulsion force, so that the movable contact is not closed with the static contact again. The contactor according to the present disclosure can prevent the movable contact and the static contact from being welded during a short circuit, and thus avoiding contactor failure and improving the reliability of the device.