Relay Controller with Time-Delayed Contact Opening
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Solution Overview
Problem
Electromechanical relays experience contact bouncing and arc formation during operation, leading to potential damage and welding of contacts due to high arc energy, especially when contacts are closed at voltage maximum or opened at current maximum, resulting in undesirable arc voltage.
Innovation Solution
Implementing a controller that opens the relay contact with a time delay when the current amplitude is rising, thereby reducing electrical loading and minimizing the formation or extinguishing of arcs, which protects the relay contact from overloading and reduces the probability of arc occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the relay contact is opened immediately upon receiving the control signal, then the response time is fast, but the arc voltage increases and the relay contact suffers from electrical overloading
Solution Approach 1:
The controller performs a preliminary assessment of the electrical variable's amplitude trend before executing the contact opening action. By sensing whether the amplitude is rising or falling in advance, the system prepares to delay the opening action if necessary, preventing harmful arc voltage while maintaining fast response when safe
Solution Approach 2:
The relay contact opening time is made dynamic rather than fixed. The controller adjusts the opening timing based on the real-time amplitude trend of the electrical variable, delaying opening only when the amplitude is rising. This dynamic adaptation resolves the contradiction between fast response and arc prevention
2Productivity
If the relay contact is opened immediately upon receiving the control signal, then the operational efficiency is high, but the relay contact reliability decreases due to contact bouncing and arc formation
Solution Approach 1:
The controller continuously monitors the electrical variable's amplitude as feedback and uses this information to determine the optimal opening time. This feedback mechanism ensures the contact opens at the safest moment (when amplitude is falling), maintaining reliability while minimizing delay to operational efficiency
Solution Approach 2:
The system performs preliminary sensing of the amplitude trend before opening the contact. This preliminary action allows the system to plan the opening timing in advance, ensuring reliability is not compromised while maintaining high operational efficiency through minimal delay
3Object-affected harmful factors
If the relay contact is opened with a time delay when rising amplitude is sensed, then the arc formation is reduced, but the response time increases
Solution Approach 1:
The delay duration is made dynamic rather than fixed. The controller applies delay only when the amplitude is rising (when arc formation is risky) and opens immediately when the amplitude is falling (when delay is unnecessary). This conditional dynamic approach reduces arc formation without unnecessarily increasing response time in safe conditions
4Power
If the relay contact is opened immediately, then the electrical loading is high, but the device complexity remains low
Solution Approach 1:
The patent replaces complex mechanical arc suppression mechanisms (such as arc chutes, magnetic blowout coils, or contact geometry modifications) with a simple electronic controller that uses sensing and timing control. This substitution reduces electrical loading through intelligent timing while keeping the added complexity minimal, as the controller only needs to sense amplitude trend and adjust opening time
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 approach effectively reduces the risk of arc formation and subsequent contact damage, extending the life of the relay by minimizing thermal loading and current spikes during the disconnection process, and reduces electromagnetic interference (EMI) emissions.
Implementation Method 1
a controller (105) which is configured to respond to the reception of the control signal by sensing a change of amplitude of the electrical variable
Implementation Method 2
there is the risk of large electrical or magnetic fields in the phase of contact bouncing, particularly when a relay contact is closed at the voltage maximum or opened at the current maximum, which can additionally result in the formation of an undesirable arc
Data Source
AI summary
The disclosure relates to a relay having a relay contact, having an electrical connection terminal at which an electrical variable can be tapped off, a control connection for receiving a control signal for opening the relay contact, and a controller. The controller is configured to respond to the reception of the control signal by sensing a change of amplitude of the electrical variable and to open the electrical relay contact with a time delay when a rising amplitude of the electrical variable is sensed, in order to reduce an electrical loading on the relay contact. The controller is further configured to respond to the reception of the control signal by opening in a first disconnection process, to sense the amplitude of the electrical variable, to close the relay contact when the rising amplitude is sensed and to open it again, with a time delay, in a second disconnection process.