Anti-interference economic relay and working method

Abstract

This invention discloses an anti-interference economic relay and its operating method, including a relay coil, armature, iron core, contacts, and an anti-interference module. The anti-interference module is a resistor-capacitor (RC) absorption circuit, which consists of a resistor and a capacitor connected in series. The anti-interference module is connected in parallel with the relay coil, with one end connected to the first terminal of the relay coil and the other end connected to the second terminal. When the current in the relay coil is cut off, the RC absorption circuit provides a release path for the reverse induced electromotive force generated by the relay coil, absorbing and dissipating its energy and suppressing voltage spikes. By effectively suppressing the induced voltage across the relay coil, this invention can eliminate malfunctions caused by the induced voltage at the source, thereby ensuring the reliable operation of the relay and improving the stability of the entire control system.

Description

Technical Field

[0001] This invention relates to the field of relay control technology, and in particular to an anti-interference economical relay and its operating method. Background Technology

[0002] In automated control systems, malfunctions of relay coils operating when not energized are common. Typically, the coil, which should be de-energized, becomes unexpectedly energized due to a sufficiently high induced voltage buildup across its terminals, causing the contacts to close or open erroneously. Such malfunctions can trigger unexpected starts or stops of electrical equipment, leading to safety accidents or the production of defective products. In control circuits involving safety interlocks, these malfunctions are more likely to directly cause dangerous operating conditions, such as equipment starting suddenly without warning.

[0003] To address the problem of relay malfunction caused by induced voltage interference, existing technologies employ safety relays. A safety relay is a special relay designed specifically for high-safety and high-reliability scenarios. It integrates complex redundant circuitry, self-diagnostic logic, and a forced-direction contact structure. These designs give it excellent resistance to electromagnetic interference (including suppression of induced voltage) and fail-safe capabilities, theoretically effectively preventing malfunctions caused by external interference (including induced voltage). Therefore, it is used in control circuits involving personal safety or the protection of critical equipment.

[0004] Although safety relays have advantages in technical performance, using them as a solution to the problem of conventional induced voltage interference presents the following main technical problems in practice: Complex structure and high difficulty in wiring and maintenance: Due to the internal structure and complex wiring process of safety relays, higher requirements are placed on the professional skills of installation, commissioning and subsequent maintenance personnel, which increases the complexity and time cost of field application; High cost, poor economic efficiency, and limited lifespan: Compared to ordinary relays, safety relays are significantly more expensive. In scenarios with strict cost control requirements, using safety relays to solve common inductive interference problems can lead to a substantial increase in overall costs. The internal relays of safety relays have a limited mechanical lifespan and must be replaced after reaching this point; otherwise, the safety level will decrease. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an anti-interference economic relay and its operating method. By effectively suppressing the induced voltage across the relay coil, this invention can eliminate malfunctions caused by the induced voltage at the source, thereby ensuring the reliable operation of the relay and improving the stability of the entire control system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides an anti-interference economical relay, comprising: Relay coil, armature, iron core, contacts, and anti-interference module; The anti-interference module is a resistor-capacitor absorption circuit, which consists of a resistor and a capacitor connected in series. The anti-interference module is connected in parallel with the relay coil, with one end of the anti-interference module connected to the first terminal of the relay coil and the other end connected to the second terminal of the relay coil. When the current in the relay coil is cut off, the RC snubber circuit provides a release path for the reverse induced electromotive force generated by the relay coil, absorbs and dissipates its energy, and suppresses voltage spikes.

[0007] As a further technical solution, the relay coil is wound on the iron core to form an electromagnetic drive mechanism; the armature can move controllably relative to the iron core; the armature is mechanically linked with the contacts to drive the contacts to switch between closed and open states when the relay coil is energized or de-energized.

[0008] As a further technical solution, the contact includes at least one set of auxiliary contacts, which includes a relay auxiliary common terminal, a normally closed contact, and a normally open contact.

[0009] As a further technical solution, the resistance value of the resistor is selected according to the critical damping condition to prevent the RC absorption circuit and the relay coil inductance from oscillating; the voltage rating of the capacitor has a margin.

[0010] As a further technical solution, the anti-interference module is installed close to the relay coil to avoid introducing new interference.

[0011] As a further technical solution, the capacitor is a CBB capacitor or an X2 safety capacitor, and the resistor is a metal film resistor or a cement resistor.

[0012] Secondly, the present invention provides a method for operating an anti-interference economic relay, based on the anti-interference economic relay provided in the first aspect, the method comprising: An AC voltage is applied across the relay coil to energize it, which drives the armature to actuate, causing the normally open contact to close and the normally closed contact to open. When the current in the relay coil is cut off, the anti-interference module connected in parallel with the relay coil absorbs and dissipates the reverse induced electromotive force generated by the relay coil.

[0013] As a further technical solution, the anti-interference module is a RC absorption circuit consisting of a resistor and a capacitor connected in series, used to absorb and dissipate the reverse induced electromotive force.

[0014] As a further technical solution, the absorption and energy dissipation satisfy the energy conservation relationship, that is, the reverse induced electromotive force generated by the relay coil when the power is off is first absorbed and stored by the capacitor in the anti-interference module, and then the energy absorbed by the capacitor is dissipated in the form of heat energy through the series resistor.

[0015] As a further technical solution, the relationship between absorption and energy dissipation is as follows: ;in, Let be the inductance of the relay coil. This is the operating current of the relay coil. This refers to the capacitance value in the anti-interference module. This is the design absorption voltage across the capacitor.

[0016] One or more technical solutions of the present invention have the following beneficial effects: This invention adds an anti-interference module, consisting of a resistor and a capacitor connected in series, to the traditional relay and connects this module in parallel with the relay coil. The structure is simple, achieved by simply adding an RC circuit (anti-interference module) to the existing relay, either externally or internally. This avoids the complex redundant circuitry and internal structure required for safety relays. Its wiring method is simply parallel connection, making installation, wiring, and maintenance very convenient, significantly reducing the difficulty of engineering implementation and the required professional skills.

[0017] The anti-interference module provided by this invention can provide a release path for the reverse induced electromotive force when the coil current is cut off, and absorb and dissipate its energy, suppress voltage spikes, effectively suppress the root cause of relay malfunction, and prevent contact malfunction by absorbing the induced energy and converting it into heat energy. This improves stability and safety.

[0018] This invention significantly improves anti-interference capabilities by integrating a low-cost anti-interference module into a common relay. This makes the invention highly cost-effective and widely applicable to numerous conventional control projects with strict cost control, solving the core pain point of safety relays being "difficult to promote and limited in applicability" due to their high price. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is an electrical connection structure diagram of an anti-interference economic relay according to the present invention; Figure 2 This is a mechanical connection structure diagram of an anti-interference economic relay according to the present invention; Figure 3 This is a schematic diagram of an anti-interference economic relay according to the present invention; Figure 4 This is a circuit diagram of an anti-interference economic relay according to the present invention. Detailed Implementation

[0021] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 This embodiment provides an anti-interference economic relay, designed to economically and effectively suppress the induced voltage generated when the relay coil is de-energized, thereby solving technical problems such as contact malfunction caused by this voltage. The anti-interference economic relay in this embodiment includes: a relay coil, an armature, an iron core, contacts, and an anti-interference module.

[0023] In this embodiment, as Figure 2 As shown, the relay coil is wound on the iron core, forming an electromagnetic drive mechanism. The armature can move in a controlled manner relative to the iron core. That is, it is attracted by the magnetic force of the iron core when the coil is energized and resets when the coil is de-energized. The armature and the contacts are mechanically linked to drive all contacts to switch between closed and open states when the relay coil is energized or de-energized.

[0024] like Figure 1 As shown, the contacts include at least one set of auxiliary contacts. In this embodiment, two sets of auxiliary contacts are specifically provided, including a common terminal for relay auxiliary contacts, a normally closed contact, and a normally open contact. Terminals 3 and 6 are the common terminals of the two auxiliary contacts of the relay. Wherein: A set of contacts with terminal 3 as the common terminal includes: a pair of normally closed contacts formed by terminals 2 and 3, and a pair of normally open contacts formed by terminals 3 and 4.

[0025] A set of contacts with terminal 6 as the common terminal includes: a pair of normally closed contacts formed by terminals 5 and 6, and a pair of normally open contacts formed by terminals 6 and 7.

[0026] In this embodiment, the anti-interference module is a resistor-capacitor (RC) snubber circuit, which consists of a resistor (R) and a capacitor (C) connected in series, such as... Figure 1As shown, the anti-interference module is connected in parallel with the relay coil as an independent component. Specifically, one end of the anti-interference module is connected to the first terminal (i.e., terminal 1) of the relay coil, and the other end is connected to the second terminal (i.e., terminal 8) of the relay coil.

[0027] In this embodiment, the capacitor (C) in the anti-interference module (RC absorption circuit) is preferably a CBB capacitor or an X2 safety capacitor, and the resistor (R) is preferably a metal film resistor or a cement resistor. In this embodiment, the capacitor C has a value of 0.1μF and a withstand voltage of not less than 630V; the resistor R has a value of 100Ω and a power rating of 1W.

[0028] The resistance (R) in the anti-interference module (RC snubber circuit) is selected based on the critical damping condition to prevent oscillation between the RC snubber circuit and the relay coil inductance. The capacitor (C) has a sufficient voltage rating to ensure safe operation under long-term 220V AC conditions.

[0029] In this embodiment, to achieve the best anti-interference effect and avoid introducing new interference, the anti-interference module should be installed as close as possible to the relay coil, and the connecting wire should be as short as possible. If installed on the control board side far from the coil, the distributed parameters (distributed inductance and capacitance) of the long connecting cable will affect the absorption effect and may even introduce new interference.

[0030] When the contacts open, the current flowing through the relay coil is cut off, and the coil (inductor) generates an extremely high reverse induced electromotive force (surge voltage) in an attempt to keep the current flowing. This high voltage is the main cause of contact erosion and electromagnetic interference.

[0031] Example 2 This embodiment provides a working method for an anti-interference economic relay, based on an anti-interference economic relay provided in Embodiment 1, specifically including a basic control process and an anti-interference process.

[0032] The basic control process includes: A 220V AC voltage is applied across the relay coil (i.e., terminals 1 and 8) to energize the coil. The magnetic field generated by the coil drives the armature to move, and the armature, through mechanical linkage, switches the states of all contacts. Specifically, normally open contacts (e.g., between terminals 3 and 4) close and conduct, while normally closed contacts (e.g., between terminals 2 and 3) open.

[0033] Anti-interference process: When the control circuit is disconnected and the current flowing through the relay coil is cut off, the relay coil (acting as an inductor) will generate an extremely high reverse induced electromotive force (surge voltage). At this time, the reverse induced electromotive force is absorbed and its energy dissipated by an anti-interference module connected in parallel with the coil (i.e., an RC absorption circuit consisting of a resistor R and a capacitor C connected in series).

[0034] In this embodiment, the absorption and energy dissipation processes satisfy the energy conservation principle. Specifically, the magnetic field energy corresponding to the reverse induced electromotive force generated by the relay coil when it is de-energized is first absorbed and stored by the capacitor (C) in the anti-interference module. Subsequently, the energy absorbed by the capacitor is slowly dissipated as heat through the resistor (R) connected in series with it.

[0035] This process can be calculated based on the law of conservation of energy: Inductive energy storage: ; Capacitors absorb energy: ; Setting the two equal, we get: ;in, Let be the inductance of the relay coil. This is the operating current of the relay coil. This refers to the capacitance value in the anti-interference module. This is the design absorption voltage across the capacitor, which is usually taken as the peak voltage of the power supply (the peak value of 220VAC is 311V, and in engineering, 250V~311V is often used as the design value).

[0036] And the capacitance can be calculated. .

[0037] Resistance calculation: The selection of resistors usually follows the critical damping condition to prevent oscillations in the absorption circuit. ; Calculation of power loss due to resistance: The resistor in the RC snubber circuit will continuously lose power during normal operation, mainly due to the charging and discharging of the capacitor by the power frequency AC voltage: ; For 220V 50Hz AC power: ; Simplified estimation: 2.42× × ; Example: hour, 2.42× ×0.1× 0.242W, therefore choosing a 1W resistor has sufficient margin.

[0038] The following are suggestions for parameter selection: Capacitor (C): Usually selected to The capacitors are connected in parallel with the 220V AC circuit. Sufficient voltage tolerance is required; it is recommended to select capacitors with a rating of 630V DC or 250V AC ~ 400V AC or higher to ensure long-term safe operation.

[0039] Resistor (R): Generally 100 is selected Up to 470 In practical applications, it is necessary to ensure that the resistor has sufficient power capacity; otherwise, it may burn out due to overheating during prolonged operation.

[0040] Typical application reference: For most small intermediate relays, the following is adopted: 100 capacitors in series Combinations of resistors can usually achieve good suppression effects.

[0041] This anti-interference module provides a low-impedance release path for the reverse induced electromotive force, effectively suppressing voltage spikes across the coil and contacts by absorbing and dissipating its energy. It can significantly reduce the induced voltage from a high level (150 V) to a low level (40 V), thereby fundamentally avoiding relay malfunctions caused by induced voltage, eliminating the conditions for contact arcing, protecting the contacts from erosion, and preventing coil insulation damage due to long-term overvoltage, ultimately improving the reliability of the entire control system.

[0042] Various modifications and variations of this invention will be apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An anti-interference economic relay, characterized in that, include: Relay coil, armature, iron core, contacts, and anti-interference module; The anti-interference module is a resistor-capacitor absorption circuit, which consists of a resistor and a capacitor connected in series. The anti-interference module is connected in parallel with the relay coil, with one end of the anti-interference module connected to the first terminal of the relay coil and the other end connected to the second terminal of the relay coil. When the current in the relay coil is cut off, the RC snubber circuit provides a release path for the reverse induced electromotive force generated by the relay coil, absorbs and dissipates its energy, and suppresses voltage spikes.

2. The anti-interference economic relay as described in claim 1, characterized in that, The relay coil is wound on the iron core to form an electromagnetic drive mechanism; the armature can move controllably relative to the iron core; the armature is mechanically linked with the contacts to drive the contacts to switch between closed and open states when the relay coil is energized or de-energized.

3. The anti-interference economic relay as described in claim 1, characterized in that, The contact includes at least one set of auxiliary contacts, which includes a relay auxiliary common terminal, a normally closed contact, and a normally open contact.

4. The anti-interference economic relay as described in claim 1, characterized in that, The resistance value is selected according to the critical damping condition to prevent oscillation between the RC absorption circuit and the relay coil inductance; the voltage rating of the capacitor has a margin.

5. The anti-interference economic relay as described in claim 1, characterized in that, The anti-interference module is installed close to the relay coil to avoid introducing new interference.

6. The anti-interference economic relay as described in claim 1, characterized in that, The capacitor is a CBB capacitor or an X2 safety capacitor, and the resistor is a metal film resistor or a cement resistor.

7. A method for operating an anti-interference economic relay, based on the anti-interference economic relay according to any one of claims 1-6, characterized in that, include: An AC voltage is applied across the relay coil to energize it, which drives the armature to actuate, causing the normally open contact to close and the normally closed contact to open. When the current in the relay coil is cut off, the anti-interference module connected in parallel with the relay coil absorbs and dissipates the reverse induced electromotive force generated by the relay coil.

8. The operating method of an anti-interference economic relay as described in claim 1, characterized in that, The anti-interference module is a resistor-capacitor absorption circuit consisting of a resistor and a capacitor connected in series, used to absorb and dissipate the reverse induced electromotive force.

9. The operating method of an anti-interference economic relay as described in claim 8, characterized in that, The absorption and energy dissipation satisfy the energy conservation relationship, that is, the reverse induced electromotive force generated by the relay coil when the power is off is first absorbed and stored by the capacitor in the anti-interference module, and then the energy absorbed by the capacitor is dissipated as heat energy through the series resistor.

10. The operating method of an anti-interference economic relay as described in claim 1, characterized in that, The relationship between absorption and energy dissipation is as follows: ;in, Let be the inductance of the relay coil. This is the operating current of the relay coil. This refers to the capacitance value in the anti-interference module. This is the design absorption voltage across the capacitor.

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