Direct-current electromagnet coil control circuit

Abstract

The utility model relates to a direct current electromagnet coil control circuit, which comprises an input circuit, a holding circuit, an action circuit, a delay starting circuit, a power-off delay reset circuit and a coil follow current circuit, the input circuit comprises a protective tube FU1, a resistor R10, an indicating lamp LED2 and a rectifier bridge D1, and the holding circuit comprises a resistor R1, a resistor R9 and a diode LED1. According to the utility model, through the optimization research on the ABB 35kV switch cabinet latching electromagnet, a latching electromagnet rectifier bridge is replaced by a latching electromagnet service life prolonging circuit, so that the latching electromagnet is switched to a holding voltage after being normally started, thereby reducing the heating of the latching electromagnet and greatly slowing down the aging speed of a latching electromagnet coil and a nylon sleeve. The service life is prolonged, faults of the latching electromagnet are reduced, and reliable operation of equipment is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of electromagnets, in particular to a direct current electromagnet coil control circuit. Background Art

[0002] 35kV switchgear is widely used in various electrical lines. Locking electromagnets are often used in 35kV switchgear. The function of the locking electromagnet is to provide a mechanical locking node for the switchgear. When it loses power, it pops up to lock the circuit breaker for electric and manual closing to prevent the danger caused by the accidental closing of the circuit breaker. It belongs to the five electrical protection functions. In daily operation, we often encounter ABB 35kV switchgear reporting closing circuit failure. Frequent inspection and analysis find that it is due to the fault of the locking electromagnet popping up, causing the closing circuit to be disconnected, resulting in the closing circuit failure.

[0003] like Figure 1 As shown, the locking electromagnet is a common electrical component. The measured coil resistance is about 9kΩ, the working voltage is DC220V, the power is U2 / R≈5.4W, and the heat is relatively large. The locking electromagnet is monitored by a thermal imager during operation. It is found that the temperature of the locking electromagnet has approached 100℃ and reached 98.8℃ after ten minutes of power-on. Long-term high-temperature operation causes the deformation of the nylon sleeve inside the electromagnet and interference with the iron core, causing jamming and the coil burning, resulting in the circuit being broken and unable to be attracted, and the coil insulation is reduced, resulting in a short circuit, causing the coil to burn out, leading to the locking electromagnet failure.

[0004] In order to solve the above-mentioned locking electromagnet failure problem, extend the life of the locking electromagnet, and at the same time enable the coil to operate reliably and maintain the operating position, we studied the relay action structure similar to the electromagnet principle. After the electromagnet's magnetic flux becomes larger, the input voltage is reduced. At this time, the electromagnet can still maintain sufficient attraction force, thereby achieving the purpose of reducing power consumption and reducing coil heating, thereby extending the service life of the electromagnet.

[0005] The relay action mechanism is composed of an electromagnet and an armature. Before the electromagnet is energized, the armature is affected by the spring force and does not contact the electromagnet. At this time, the magnetic circuit passes through the air. Since the magnetic permeability of air is low, the electromagnet requires a higher current to ensure reliable action. The resistance of the electromagnet is fixed, so the voltage required to reach the action current is also relatively fixed. This is one of the important parameters of the relay, the action voltage. When the relay is activated, the armature and the electromagnet change to direct contact. At this time, the magnetic permeability is greatly improved, and the electromagnet does not need to flow a higher current to overcome the traction of the spring to maintain the action state. Since the coil resistance is fixed, the voltage to reach the required current is also fixed, and this voltage is the holding voltage.

[0006] Similarly, before and after the electromagnet is actuated, the magnetic flux is similar to the relay action process. If after the action, the action voltage is converted to the holding voltage, the magnetic flux increases, and the holding voltage can also keep the electromagnet position unchanged, while the electromagnet power consumption is greatly reduced. Therefore, it is necessary to design a locking electromagnet to extend its life. Utility Model Content

[0007] The utility model provides a direct current electromagnet coil control circuit to solve the problems of heating, short circuit and the like mentioned in the prior art.

[0008] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0009] A DC electromagnet coil control circuit comprises an input circuit, a holding circuit, an action circuit, a freewheeling delay start circuit, a power-off delay reset circuit and a coil freewheeling circuit, characterized in that the input circuit comprises a fuse FU1, a resistor R10, an indicator light LED2 and a rectifier bridge D1, the holding circuit comprises a resistor R1, a resistor R9 and a diode LED1, the action circuit comprises a resistor R7, a transistor Q1 and a transistor Q2, the delay start circuit comprises a resistor R2, a capacitor C2 and a transistor Q5, the power-off delay reset circuit comprises a diode D2, a transistor Q4, a resistor R4, a resistor R8, a capacitor C1, a resistor R5, a resistor R6 and a transistor Q3, the coil freewheeling circuit comprises a diode D3, a port 2 of the rectifier bridge D1 is connected to a voltage input terminal I NPUT1, and a port 1 of the rectifier bridge D1 is connected to a voltage input terminal I NPUT2 through a fuse FU1. NPUT2, port 3 of the rectifier bridge D1 is connected to resistors R2, R7, R4, R10, the cathode of diode D3, the locking electromagnet interface K+ and the anode of diode D2, the cathode of diode D2 is connected to resistors R3 and R8, the other end of resistor R10 is connected to indicator LED2, the other end of resistor R8 is connected to capacitor C1 and the emitter of transistor Q4, the base of transistor Q4 is connected to the other end of resistor R4, the collector of transistor Q4 is connected to resistor R5, the other end of resistor R5 is connected to resistor R6 and the base of transistor Q3, the collector of transistor Q3 is connected to capacitor C2, resistor R2 and the base of transistor Q5 The other end of the resistor R7 is connected to the collector of the transistor Q5 and the base of the transistor Q1, the collector of the transistor Q1 is connected to the anode of the diode D3, the collector of the transistor Q2, the resistor R1, the resistor R9 and the locking electromagnet interface K-, the other end of the resistor R9 is connected to the indicator light LED1, and the port 4 of the rectifier bridge D1 is connected to the other end of the indicator light LED2, the other end of the capacitor C2, the anode of the diode D3, the other end of the resistor R6, the emitter of the transistor Q3, the other end of the capacitor C1, the emitter of the transistor Q5, the emitter of the transistor Q2, the other end of the resistor R1, the other end of the resistor R3 and the other end of the indicator light LED1.

[0010] As a further technical solution of the utility model: the transistor Q1 is an NPN transistor.

[0011] As a further technical solution of the utility model: the transistor Q2 is an NPN transistor.

[0012] As a further technical solution of the utility model: the transistor Q3 is an NPN transistor.

[0013] As a further technical solution of the utility model: the transistor Q4 is a PNP transistor.

[0014] As a further technical solution of the utility model: the transistor Q5 is an NPN transistor.

[0015] In the above technical solution, the technical effects and advantages provided by the utility model are:

[0016] The utility model optimizes the locking electromagnet of ABB 35kV switch cabinet and replaces the locking electromagnet rectifier bridge with a "DC electromagnet coil control circuit" so that the locking electromagnet switches to a holding voltage after normal startup, thereby reducing the heating of the locking electromagnet, greatly slowing down the aging speed of the locking electromagnet coil and the nylon sleeve, extending the service life, reducing the occurrence of locking electromagnet failures, and ensuring reliable operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A circuit diagram of the prior art of the utility model;

[0019] Figure 2 This is a circuit function flow chart of the utility model;

[0020] Figure 3 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] It should be noted that the terms “vertical”, “horizontal”, “up”, “down”, “left”, “right” and similar expressions used in this document are only for illustrative purposes and do not represent the only implementation method.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention; the terms used in the specification of the present invention are only for the purpose of describing specific implementation methods and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] The utility model provides Figure 2-Figure 3The drawings shown are specifically a DC electromagnet coil control circuit, including an input circuit, a holding circuit, an action circuit, a freewheeling delay start circuit, a power-off delay reset circuit and a coil freewheeling circuit, characterized in that the input circuit includes a fuse FU1, a resistor R10, an indicator light LED2 and a rectifier bridge D1, the holding circuit includes a resistor R1, a resistor R9 and a diode LED1, the action circuit includes a resistor R7, a transistor Q1 and a transistor Q2, the delay start circuit includes a resistor R2, a capacitor C2 and a transistor Q5, the power-off delay reset circuit includes a diode D2, a transistor Q4, a resistor R4, a resistor R8, a capacitor C1, a resistor R5, a resistor R6 and a transistor Q3, the coil freewheeling circuit includes a diode D3, port 2 of the rectifier bridge D1 is connected to the voltage input terminal I NPUT1, and port 1 of the rectifier bridge D1 is connected to the voltage input terminal I through the fuse FU1. NPUT2, port 3 of the rectifier bridge D1 is connected to resistors R2, R7, R4, R10, the cathode of diode D3, the locking electromagnet interface K+ and the anode of diode D2, the cathode of diode D2 is connected to resistors R3 and R8, the other end of resistor R10 is connected to indicator LED2, the other end of resistor R8 is connected to capacitor C1 and the emitter of transistor Q4, the base of transistor Q4 is connected to the other end of resistor R4, the collector of transistor Q4 is connected to resistor R5, the other end of resistor R5 is connected to resistor R6 and the base of transistor Q3, the collector of transistor Q3 is connected to capacitor C2, resistor R2 and the base of transistor Q5 The other end of the resistor R7 is connected to the collector of the transistor Q5 and the base of the transistor Q1, the collector of the transistor Q1 is connected to the anode of the diode D3, the collector of the transistor Q2, the resistor R1, the resistor R9 and the locking electromagnet interface K-, the other end of the resistor R9 is connected to the indicator light LED1, and the port 4 of the rectifier bridge D1 is connected to the other end of the indicator light LED2, the other end of the capacitor C2, the anode of the diode D3, the other end of the resistor R6, the emitter of the transistor Q3, the other end of the capacitor C1, the emitter of the transistor Q5, the emitter of the transistor Q2, the other end of the resistor R1, the other end of the resistor R3 and the other end of the indicator light LED1.

[0025] Here’s how it works:

[0026] Input circuit: Use fuse FU1 for short-circuit protection, and rectifier bridge D1 processes the input voltage, so there is no need to distinguish between positive and negative poles, which improves the speed of installation and replacement. R10 and LED2 are used to display the power input.

[0027] In the holding circuit, the R1 resistor is used to limit the current of the locking electromagnet. R9 and LED1 are used to display the holding voltage and can also be used as a coil on-off display to quickly determine the cause of the fault.

[0028] The freewheeling circuit will only work when the power is off. The coil is essentially an inductor. When the power is off, it will reversely induce a high-voltage spike. This high-voltage spike can easily break down and damage other electronic components. The purpose of adding this diode is to freewheel, short-circuit and consume the reverse high-voltage spike to protect the circuit.

[0029] The action circuit is composed of R7 and two transistors Q1 and Q2. Since the amplification factor of transistors with higher withstand voltage is generally smaller, two high withstand voltage transistors are used to form a Darlington transistor, which increases the amplification factor from β times of the original single tube to β*β times. This can greatly increase the value of the base resistance and reduce power loss and heat.

[0030] Delay start circuit: It is composed of R2, C2 and a Q5 transistor. When the power is turned on, the capacitor is charged. When the capacitor voltage exceeds 0.6V, Q5 is turned on, and the base voltage of Q1 is pulled down, so that the Darlington transistor is turned off. At this time, it switches to the holding circuit to reduce the latching electromagnet current.

[0031] The power-off delay reset circuit charges the C1 capacitor through the D2 diode when the power is on. When the power is off, the Q4 transistor turns on, making the Q3 transistor conduct, discharging the delayed start C2 capacitor (delay reset). When the power is on again, the Q4 transistor will turn off, and the Q3 transistor will also turn off synchronously, and the circuit will return to the initial power-on state.

[0032] By testing the locking electromagnet, the LED2 power indicator light is on at the moment of power-on, the electromagnet can reliably operate at 220V voltage and switch to the holding voltage of about 120V after a delay of about 1s, and the power drops from 5.4W to 1.6W. At the same time, LED1 lights up, and the suction force of the electromagnet is sufficient to keep it in the suction position. After power failure, the electromagnet can lose power immediately, LED1 and LED2 go out at the same time, and the above process can be repeated after power is restored. Unplug the power cord of the locking electromagnet to simulate the disconnection of the locking electromagnet, and LED1 goes out instantly. It can be judged that the locking electromagnet is short-circuited, which meets the design requirements. Under the room temperature of 26℃, use DC220V power supply and add the locking electromagnet life extension circuit to carry the load for 2 hours respectively. After the electromagnet temperature tends to be constant, the temperature of the locking electromagnet powered by DC220V reaches 120℃, and the temperature of the locking electromagnet powered by the locking electromagnet life extension circuit is 70℃, which can greatly slow down the aging speed and extend the service life of the electromagnet.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0034] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment have also been appropriately combined to form other implementation methods that are easy for those skilled in the art to understand.

Claims

1. A DC electromagnet coil control circuit, comprising an input circuit, a holding circuit, an action circuit, a freewheeling delay start circuit, a power-off delay reset circuit and a coil freewheeling circuit, characterized in that: The input circuit includes a fuse FU1, a resistor R10, an indicator light LED2 and a rectifier bridge D1, a holding circuit includes a resistor R1, a resistor R9 and a diode LED1, an action circuit includes a resistor R7, a transistor Q1 and a transistor Q2, a delayed start circuit includes a resistor R2, a capacitor C2 and a transistor Q5, a power-off delay reset circuit includes a diode D2, a transistor Q4, a resistor R4, a resistor R8, a capacitor C1, a resistor R5, a resistor R6 and a transistor Q3, a coil freewheeling circuit includes a diode D3, a port 2 of the rectifier bridge D1 is connected to a voltage input terminal INPUT1, a port 1 of the rectifier bridge D1 is connected to a voltage input terminal INPUT2 through a fuse FU1, a port 3 of the rectifier bridge D1 is connected to resistors R2, R7, R4, R10, a cathode of a diode D3, a locking electromagnet interface K+ and an anode of a diode D2, a cathode of a diode D2 is connected to resistors R3 and R8, the other end of the resistor R10 is connected to an indicator light LED2, and a capacitor C2 is connected to a transistor Q3. The other end of resistor R8 is connected to capacitor C1 and the emitter of transistor Q4, the base of transistor Q4 is connected to the other end of resistor R4, the collector of transistor Q4 is connected to resistor R5, the other end of resistor R5 is connected to resistor R6 and the base of transistor Q3, the collector of transistor Q3 is connected to capacitor C2, resistor R2 and the base of transistor Q5, the other end of resistor R7 is connected to the collector of transistor Q5 and the base of transistor Q1, the collector of transistor Q1 is connected to the anode of diode D3, the transistor The collector of transistor Q2, resistor R1, resistor R9 and locking electromagnet interface K-, the other end of resistor R9 is connected to indicator light LED1, port 4 of rectifier bridge D1 is connected to the other end of indicator light LED2, the other end of capacitor C2, the anode of diode D3, the other end of resistor R6, the emitter of transistor Q3, the other end of capacitor C1, the emitter of transistor Q5, the emitter of transistor Q2, the other end of resistor R1, the other end of resistor R3 and the other end of indicator light LED1.

2. A DC electromagnet coil control circuit according to claim 1, characterized in that: The transistor Q1 is an NPN transistor.

3. A DC electromagnet coil control circuit according to claim 1, characterized in that: The transistor Q2 is an NPN transistor.

4. A DC electromagnet coil control circuit according to claim 1, characterized in that: The transistor Q3 is an NPN transistor.

5. A DC electromagnet coil control circuit according to claim 1, characterized in that: The transistor Q4 is a PNP transistor.

6. A DC electromagnet coil control circuit according to claim 1, characterized in that: The transistor Q5 is an NPN transistor.

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