Electromagnetic Relay Coil Voltage Control for Low-Noise Switching
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Solution Overview
Problem
Existing electromagnetic relays face challenges with high costs, complex control systems, and reduced service life due to noise interference and heat generation, which are not adequately addressed by existing noise reduction and elastic structure modifications.
Innovation Solution
A control system for electromagnetic relays incorporating an electromagnet coil, a resistor, and a voltage control element, such as a capacitor, that gradually adjusts the voltage across the electromagnet coil to control the electromagnetic force applied to the armature iron, reducing impact speed and ensuring proper contact point engagement, thereby reducing noise and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large electromagnetic field is used to attract the armature iron, then the contact points can be reliably connected or disconnected, but the impact speed increases causing large noise
Solution Approach 1:
The patent applies preliminary action by using a first voltage control element (capacitor) to gradually increase the voltage across the electromagnet coil from 0 to rated voltage during power-on, and gradually decrease it during power-off. This gradual voltage change causes the electromagnetic field and armature iron acceleration to build up or reduce progressively rather than abruptly, reducing impact speed and noise while ensuring reliable contact point engagement is achieved.
Solution Approach 2:
The patent employs periodic action through the charging and discharging cycles of the capacitor in the voltage control circuit. The capacitor charges gradually when power is applied and discharges gradually when power is removed, creating a time-dependent periodic control pattern that modulates the electromagnetic field strength, thereby controlling armature motion speed and reducing impact noise.
2Reliability
If the disconnection distance of contact points is increased to avoid electric arc discharge, then the armature iron movement distance increases, but a larger electromagnetic field is required which increases impact speed and noise
Solution Approach 1:
The capacitor-based voltage control implements preliminary action by preparing the electromagnetic field gradually before full armature movement occurs. The gradual voltage increase allows the magnetic field to build up progressively, reducing the shock impact when the armature reaches the contact points, even though the movement distance remains sufficient to prevent electric arc discharge.
3Reliability
If a large contact force is applied to maintain good contact, then contact resistance decreases, but heat generation increases
Solution Approach 1:
The periodic charging and discharging of the capacitor creates a time-varying electromagnetic field that applies contact force in a controlled manner. The gradual voltage changes result in smoother armature acceleration and deceleration, reducing impact forces and associated heat generation while maintaining adequate contact force for low contact resistance.
4Object-affected harmful factors
If existing noise reduction methods are used (sealing and sound absorption material), then noise may be reduced, but additional structures and costs are added and heat dissipation is compromised
Solution Approach 1:
The patent replaces mechanical noise reduction methods (sealing structures and sound absorption materials) with an electrical control approach. By using voltage control elements to gradually modulate the electromagnetic field, the armature impact speed is reduced at the source, eliminating noise without adding mechanical structures that would complicate the device and impede heat dissipation.
5Object-affected harmful factors
If segmental current control is implemented, then noise reduction may be achieved, but additional control circuits are required making the system complex and costly
Solution Approach 1:
The patent changes the electrical parameters (voltage and current) of the electromagnet coil gradually over time using passive voltage control elements (capacitors and resistors). This parameter change approach achieves noise reduction through natural RC circuit charging/discharging characteristics, eliminating the need for complex active control circuits with multiple switches and control logic.
Solution Approach 2:
The voltage control circuit using capacitors and resistors is self-regulating through natural electrical properties. The RC time constants automatically determine the voltage rise and fall rates without requiring external control signals or complex control logic, making the system simple and cost-effective while achieving gradual current control for noise reduction.
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 effectively reduces noise and heat generation, improving the service life of the electromagnetic relay by gradually controlling the electromagnetic field and force, thus avoiding large impact speeds and ensuring consistent contact point engagement.
Implementation Method 1
A small current is applied to the electromagnet of the input circuit to generate an electromagnetic force to control the movement of the armature iron
Implementation Method 2
The first voltage control element is a capacitor... When the electromagnet coil changes from a power-off state to a power-on state, the voltage across the electromagnet coil gradually increases from 0 to a rated voltage under the control of the first voltage control element
Implementation Method 3
A first terminal of the electromagnet coil is connected to a first terminal of a first power circuit through the first resistor
Data Source
AI summary
Provided are a control system of an electromagnetic relay and an electromagnetic relay. The control system of an electromagnetic relay includes an electromagnet coil, a first resistor, and a first voltage control element. A first terminal of the electromagnet coil is connected to a first terminal of a first power circuit through the first resistor. A second terminal of the electromagnet coil is connected to a second terminal of the first power circuit. The first voltage control element is connected in parallel to the electromagnet coil. The first voltage control element can control the magnitude of the voltage across the electromagnet coil, so that the force to which armature iron is subjected gradually changes.