Relay Coil Current Sequencing to Suppress Inrush Current
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Solution Overview
Problem
Existing relay control methods require high-rated current components due to large inrush currents during switching, leading to increased costs for relay and peripheral circuit components.
Innovation Solution
A relay control device with a switching current output circuit and a holding current output circuit, where the switching current is applied after a delay from the initiation of the holding current, using a current limiting resistor to reduce inrush current peak and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If switching current is applied immediately to the coil, then the relay switches from open to closed state quickly, but large inrush current flows causing high-rated components to be required
Solution Approach 1:
The patent applies preliminary action by first applying holding current through the holding current output circuit before applying switching current through the switching current output circuit. This sequence ensures the armature is already in the closed state when switching current is applied, preventing inrush current while maintaining quick switching response.
Solution Approach 2:
The patent segments the current application process into two distinct phases: holding current application (first current) and switching current application (second current), controlled by separate output circuits. This segmentation allows each circuit to be optimized for its specific function while avoiding the harmful inrush current effect.
2Object-affected harmful factors
If holding current is applied before switching current, then inrush current is suppressed, but the control sequence becomes more complex
Solution Approach 1:
The patent implements self-service by designing the control unit to automatically manage the sequencing of holding and switching current application. The control unit monitors the states of both output circuits and autonomously determines when to apply or stop current based on the relay's operational state, eliminating the need for external complex control logic.
3Speed
If switching current output circuit applies current immediately, then relay response is fast, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by first applying holding current through the holding current output circuit before applying switching current through the switching current output circuit. This sequence ensures the armature is already in the closed state when switching current is applied, preventing inrush current while maintaining quick switching response.
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 configuration suppresses inrush currents, allowing the use of lower-rated, cost-effective components and reducing power consumption during the relay's closed state.
Implementation Method 1
a movable iron armature having a first end connected with the second power supply, the movable iron armature being switched from an open state to a closed state when the coil is excited
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A relay control device (100) includes a coil (3), a movable iron armature (4) that is switched from an open state to a closed state when the coil (3) is excited, a switching current output circuit that applies first current for switching the movable iron armature (4) from the open state to the closed state to the coil (3), and a holding current output circuit that applies second current for holding the movable iron armature (4) in the closed state to the coil (3). The switching current output circuit applies the first current to the coil (3) when a first time has elapsed from when the second current is started to be applied to the coil (3), and the value of the second current is lower than the value of the first current.