Mining flame-proof and intrinsically safe low-voltage non-contact switch circuit

Abstract

This utility model provides a mine-use explosion-proof and intrinsically safe low-voltage contactless switch circuit, including: a main circuit, a control circuit, a transformer TC, and a comprehensive controller JZK1; the main circuit includes a reversing switch QS, one side of which is used to connect to the incoming three-phase live wires X1, X2, and X3, and the other side is connected to the power supply three-phase live wires XA, XB, and XC respectively through fuses KR1, KR2, and KR3; the first terminals of bidirectional thyristors MTC1, MTC2, and MTC3 are respectively connected to the power supply three-phase live wires XA, XB, and XC. The second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the three-phase power terminals of the three-phase motor M1 via three-phase lines; the first and second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding voltage detection terminals of the integrated controller JZK1; and the gate terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding gate control terminals of the integrated controller JZK1. This circuit is safer and more reliable for long-term use, and also realizes the soft-start function of the motor.

Description

Technical Field

[0001] This utility model relates to a control circuit for mining, and more particularly to a low-voltage contactless switch circuit for mining that is both explosion-proof and intrinsically safe. Background Technology

[0002] In the mining industry, explosion-proof electromagnetic starters are widely used in the control of low-power equipment such as 1140 / 660V fans, water pumps, and compressors, especially for the start and stop control of motors. The electromagnetic starter uses electromagnetic principles, controlling the opening and closing of the main circuit through the energization and de-energization of the coil. When current flows through the electromagnetic coil, a magnetic field is generated, attracting the iron core or actuating parts, causing the electrical switch to operate, thus connecting or disconnecting the circuit. After energization, the electromagnet's attraction closes the contacts, allowing the motor to start; when the current is cut off, the electromagnet loses its attraction, the contacts open, and the motor stops.

[0003] Explosion-proof electromagnetic starters for mining play a vital role in the mining environment, but they have some drawbacks. For example, the main switch of an explosion-proof electromagnetic starter uses a vacuum contactor, which controls the closing or opening of the vacuum tube contacts by the energization of the coil. Since the starter operates on a frequent-duty basis, the contacts experience electrical wear after prolonged use, leading to poor contact. Furthermore, the contactor coil is prone to insulation damage in humid environments, resulting in short circuits and burnout. Traditional electromagnetic starters generally rely on motor protectors for protection, providing basic overload and short-circuit protection. However, under complex load conditions, they cannot effectively monitor and identify dynamic overload situations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this utility model provides a mining-grade explosion-proof and intrinsically safe low-voltage contactless switch circuit. It utilizes a bidirectional thyristor to control the motor's on / off state, avoiding faults caused by poor contact in the main circuit, thus ensuring greater safety and reliability over long-term use. It also enables soft-start functionality for the motor. To achieve the above technical objectives, the technical solution adopted in this utility model embodiment is as follows:

[0005] This utility model embodiment provides a mine-use explosion-proof and intrinsically safe low-voltage contactless switch circuit, including: a main circuit, a control circuit, a transformer TC, and a comprehensive controller JZK1;

[0006] The main circuit includes a reversing switch QS. One side of the reversing switch QS is used to connect to the incoming three-phase live wires X1, X2, and X3, and the other side is connected to the power supply three-phase live wires XA, XB, and XC via fuses KR1, KR2, and KR3, respectively. The first terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the power supply three-phase live wires XA, XB, and XC, respectively, and the second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the three-phase power terminals of the three-phase motor M1 via three-phase lines. The first and second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding voltage detection terminals of the integrated controller JZK1, respectively. The gate terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding terminals of the integrated controller JZK1, respectively. The gate control terminal is provided; current transformers LH1, LH2, and LH3 are installed on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the first terminals of current transformers LH1, LH2, and LH3 are respectively connected to the three current sampling terminals of the integrated controller JZK1, and the second terminals of current transformers LH1, LH2, and LH3 are connected to the common current sampling terminal of the integrated controller JZK1; an RC-8 resistor-capacitor absorber is also connected on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the resistance detection terminal RJ of the integrated controller JZK1 is connected to one phase of the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1;

[0007] The integrated controller JZK1 includes fault detection switches BHQ1 and BHQ2. Before the bidirectional thyristors MTC1, MTC2, and MTC3 are closed, if the integrated controller JZK1 performs a self-test and finds no fault, the fault detection switch BHQ1 will close; otherwise, the fault detection switch BHQ1 will open. After the bidirectional thyristors MTC1, MTC2, and MTC3 are closed, if the integrated controller JZK1 performs a self-test and finds no fault, the fault detection switch BHQ2 will close; otherwise, the fault detection switch BHQ2 will open.

[0008] The primary side of the transformer TC is connected to two of the three-phase live wires XA, XB, and XC via fuses FU4 and FU5 respectively; the secondary side of the transformer TC is connected to the first terminal of the first section and the first terminal of the second section of the air switch ZK1 respectively; the second terminal of the first section and the second terminal of the second section of the air switch ZK1 are respectively connected to the two ends of the control circuit.

[0009] The control circuit includes a fault detection switch BHQ1, a closing switch SB1, a normally open contact KA1-1 of a relay KA1, a tripping switch SB2, a fault detection switch BHQ2, and a relay KA1 coil; the fault detection switch BHQ1, the closing switch SB1, the tripping switch SB2, the fault detection switch BHQ2, and the relay KA1 coil are connected in series; the normally open contact KA1-1 of the relay KA1 is connected in parallel across the closing switch SB1.

[0010] The integrated controller JZK1 is provided with a control input terminal and a control common terminal. The control input terminal includes a start / stop control terminal, which is connected to one end of the normally open contact KA1-2 of relay KA1, and the other end of the normally open contact KA1-2 of relay KA1 is connected to the control common terminal. The two power supply input terminals of the integrated controller JZK1 are respectively connected to the two ends of the secondary side of transformer TC.

[0011] Furthermore, the control circuit also includes an electrical interlock contact KB1; the electrical interlock contact KB1 is connected in series in the control circuit.

[0012] Furthermore, the control input terminals on the integrated controller JZK1 also include a confirmation input terminal, a reset input terminal, and a shift input terminal; the confirmation input terminal is connected to one end of the confirmation button QR, and the other end of the confirmation button QR is connected to the common control terminal; the reset input terminal is connected to one end of the reset button FW, and the other end of the reset button FW is connected to the common control terminal; the shift input terminal is connected to one end of the shift button YW, and the other end of the shift button YW is connected to the common control terminal; the integrated controller JZK1 also has a display screen.

[0013] Furthermore, the control input terminals on the integrated controller JZK1 also include a gas alarm input terminal and a fan alarm input terminal; the gas alarm input terminal is connected to one end of the normally open contact WS of the gas sensor, and the other end of the normally open contact WS of the gas sensor is connected to the common control terminal; the fan alarm input terminal is connected to one end of the normally open contact FD of the fan fault detection, and the other end of the normally open contact FD of the fan fault detection is connected to the common control terminal.

[0014] Furthermore, the integrated controller JZK1 also includes a communication port for communicating with a host computer.

[0015] The beneficial effects of the technical solution provided by this utility model embodiment are:

[0016] 1) High reliability, capable of long-term use, avoiding contact failure of contactor contacts in the main circuit.

[0017] 2) It can achieve soft start of motor, effectively reducing the impact of motor starting process on the power grid.

[0018] 3) It is lighter and smaller than existing electromagnetic starters. Attached Figure Description

[0019] Figure 1 This is an electrical schematic diagram of the low-voltage contactless switch circuit in an embodiment of this utility model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0021] like Figure 1 As shown in the figure, the mine explosion-proof and intrinsically safe low-voltage contactless switch circuit proposed in this embodiment includes: a main circuit, a control circuit, a transformer TC, and a comprehensive controller JZK1;

[0022] The main circuit includes a reversing switch QS. One side of the reversing switch QS is used to connect to the incoming three-phase live wires X1, X2, and X3, and the other side is connected to the power supply three-phase live wires XA, XB, and XC via fuses KR1, KR2, and KR3, respectively. The first terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the power supply three-phase live wires XA, XB, and XC, respectively. The second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the three-phase power terminals of the three-phase motor M1 via three-phase lines. The first and second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding voltage detection terminals of the integrated controller JZK1, respectively. Figure 1 K1~K6 in the diagram); the gate terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are respectively connected to the corresponding gate control terminals of the integrated controller JZK1 ( Figure 1 (G1~G6 in the diagram); Current transformers LH1, LH2, and LH3 are installed on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the first terminals of current transformers LH1, LH2, and LH3 are respectively connected to the three current sampling terminals of the integrated controller JZK1, and the second terminals of current transformers LH1, LH2, and LH3 are connected together and connected to the common current sampling terminal of the integrated controller JZK1; a resistor-capacitor RC-8 is also connected on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the resistance detection terminal RJ of the integrated controller JZK1 is connected to one phase of the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1;

[0023] The integrated controller JZK1 includes fault detection switches BHQ1 and BHQ2. Before the bidirectional thyristors MTC1, MTC2, and MTC3 are closed (i.e., turned on), if the integrated controller JZK1 performs a self-test and finds no fault, fault detection switch BHQ1 closes; otherwise, fault detection switch BHQ1 opens. After the bidirectional thyristors MTC1, MTC2, and MTC3 are closed (i.e., turned on), if the integrated controller JZK1 performs a self-test and finds no fault, fault detection switch BHQ2 closes; otherwise, fault detection switch BHQ2 opens. For example, before the bidirectional thyristors MTC1, MTC2, and MTC3 are closed (i.e., turned on), the integrated controller JZK1 can detect whether there is a short circuit fault in the main circuit through the resistance detection terminal RJ; after the bidirectional thyristors MTC1, MTC2, and MTC3 are closed (i.e., turned on), the integrated controller JZK1 can detect whether there is an overvoltage or overcurrent fault in the main circuit.

[0024] The primary side of the transformer TC is connected to two of the three-phase live wires XA, XB, and XC via fuses FU4 and FU5 respectively; the secondary side of the transformer TC is connected to the first terminal of the first section and the first terminal of the second section of the air switch ZK1 respectively; the second terminal of the first section and the second terminal of the second section of the air switch ZK1 are respectively connected to the two ends of the control circuit.

[0025] The control circuit includes a fault detection switch BHQ1, a closing switch SB1, a normally open contact KA1-1 of a relay KA1, a tripping switch SB2, a fault detection switch BHQ2, and a relay KA1 coil; the fault detection switch BHQ1, the closing switch SB1, the tripping switch SB2, the fault detection switch BHQ2, and the relay KA1 coil are connected in series; the normally open contact KA1-1 of the relay KA1 is connected in parallel across the closing switch SB1.

[0026] The integrated controller JZK1 is equipped with a control input terminal and a control common terminal ( Figure 1 (24+ in the text), the control input terminal includes a start / stop control terminal, which is connected to one end of the normally open contact KA1-2 of relay KA1, and the other end of the normally open contact KA1-2 of relay KA1 is connected to the control common terminal; the two power supply input terminals of the integrated controller JZK1 are respectively connected to the two ends of the secondary side of transformer TC;

[0027] After the integrated controller JZK1 performs a power-on self-test, if no fault is found, the fault detection switch BHQ1 closes. At this point, the closing switch SB1 can be closed, energizing the coil of relay KA1. The normally open contact KA1-1 of relay KA1 closes, causing relay KA1 to self-hold energized. The normally open contact KA1-2 of relay KA1 closes, and the integrated controller JZK1 receives a closing control signal, controlling the bidirectional thyristors MTC1, MTC2, and MTC3 to close (i.e., conduct). The bidirectional thyristors MTC1, MTC2, and MTC3 replace the existing vacuum contactors in the main circuit, avoiding the need for... The fault is poor contact of the contactor. For loads with different power ratings, different rated current bidirectional thyristors can be selected, such as MTC-125A-2500V, MTC-250A-2500V, and MTC-325A-2500V. The contactless switch circuit proposed in this embodiment has higher reliability in long-term use, and is lighter and smaller while meeting the explosion-proof requirements for mining applications. During motor startup, by gradually changing the conduction angle of the bidirectional thyristors in the main circuit, the motor has soft-start capability, effectively reducing the impact of the motor startup process on the power grid. During motor operation, if an overvoltage or overcurrent fault is detected, the fault detection switch BHQ2 will open, the relay KA1 coil will be de-energized, the normally open contact KA1-2 of relay KA1 will open, and the integrated controller JZK1 will receive a tripping control signal, controlling the bidirectional thyristors MTC1, MTC2, and MTC3 to trip (i.e., disconnect).

[0028] More preferably, the control circuit further includes an electrical interlock contact KB1; the electrical interlock contact KB1 is connected in series in the control circuit; the electrical interlock contact KB1 enables the external device to achieve linkage control with the low-voltage contactless switch circuit proposed in this application; the fault switch on the external device can be connected to the electrical interlock contact KB1; if there is a fault alarm on the external device, the fault switch on the external device is opened, the electrical interlock contact KB1 is disconnected, the coil of relay KA1 is de-energized, the normally open contact KA1-2 of relay KA1 is opened, the integrated controller JZK1 receives the trip control signal, and controls the bidirectional thyristors MTC1, MTC2, and MTC3 to trip (i.e. disconnect).

[0029] More preferably, the control input terminals on the integrated controller JZK1 further include a confirmation input terminal, a reset input terminal, and a shift input terminal; the confirmation input terminal is connected to one end of the confirmation button QR, and the other end of the confirmation button QR is connected to the common control terminal; the reset input terminal is connected to one end of the reset button FW, and the other end of the reset button FW is connected to the common control terminal; the shift input terminal is connected to one end of the shift button YW, and the other end of the shift button YW is connected to the common control terminal; the integrated controller JZK1 is also equipped with a display screen; the confirmation button QR, the reset button FW, and the shift button YW are used to operate in conjunction with the display screen.

[0030] More preferably, the control input terminals on the integrated controller JZK1 also include a gas alarm input terminal and a fan alarm input terminal; the gas alarm input terminal is connected to one end of the normally open contact WS of the gas sensor, and the other end of the normally open contact WS is connected to the common control terminal; the fan alarm input terminal is connected to one end of the normally open contact FD of the fan fault detection, and the other end of the normally open contact FD is connected to the common control terminal; when a gas situation or fan failure occurs in the mine, the normally open contact WS of the gas sensor or the normally open contact FD of the fan fault detection can issue an alarm signal, and the integrated controller JZK1 receives the alarm signal and controls the bidirectional thyristors MTC1, MTC2, and MTC3 to trip (i.e. disconnect).

[0031] More preferably, the integrated controller JZK1 also includes a communication port for communicating with a host computer so that remote control can be performed; in this embodiment, the communication port of the integrated controller JZK1 is an RS485 port.

[0032] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A mining explosion-proof and intrinsically safe low-voltage contactless switch circuit, characterized in that, include: Main circuit, control circuit, transformer TC, integrated controller JZK1; The main circuit includes a reversing switch QS. One side of the reversing switch QS is used to connect to the incoming three-phase live wires X1, X2, and X3, and the other side is connected to the power supply three-phase live wires XA, XB, and XC via fuses KR1, KR2, and KR3, respectively. The first terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the power supply three-phase live wires XA, XB, and XC, respectively, and the second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the three-phase power terminals of the three-phase motor M1 via three-phase lines. The first and second terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding voltage detection terminals of the integrated controller JZK1, respectively. The gate terminals of the bidirectional thyristors MTC1, MTC2, and MTC3 are connected to the corresponding terminals of the integrated controller JZK1, respectively. The gate control terminal is provided; current transformers LH1, LH2, and LH3 are installed on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the first terminals of current transformers LH1, LH2, and LH3 are respectively connected to the three current sampling terminals of the integrated controller JZK1, and the second terminals of current transformers LH1, LH2, and LH3 are connected to the common current sampling terminal of the integrated controller JZK1; an RC-8 resistor-capacitor absorber is also connected on the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; the resistance detection terminal RJ of the integrated controller JZK1 is connected to one phase of the three-phase line between the bidirectional thyristors MTC1, MTC2, and MTC3 and the three-phase motor M1; The integrated controller JZK1 includes fault detection switches BHQ1 and BHQ2. Before the bidirectional thyristors MTC1, MTC2, and MTC3 are closed, if the integrated controller JZK1 performs a self-test and finds no fault, the fault detection switch BHQ1 will close; otherwise, the fault detection switch BHQ1 will open. After the bidirectional thyristors MTC1, MTC2, and MTC3 are closed, if the integrated controller JZK1 performs a self-test and finds no fault, the fault detection switch BHQ2 will close; otherwise, the fault detection switch BHQ2 will open. The primary side of the transformer TC is connected to two of the three-phase live wires XA, XB, and XC via fuses FU4 and FU5 respectively; the secondary side of the transformer TC is connected to the first terminal of the first section and the first terminal of the second section of the air switch ZK1 respectively; the second terminal of the first section and the second terminal of the second section of the air switch ZK1 are respectively connected to the two ends of the control circuit. The control circuit includes a fault detection switch BHQ1, a closing switch SB1, a normally open contact KA1-1 of a relay KA1, a tripping switch SB2, a fault detection switch BHQ2, and a relay KA1 coil; the fault detection switch BHQ1, the closing switch SB1, the tripping switch SB2, the fault detection switch BHQ2, and the relay KA1 coil are connected in series; the normally open contact KA1-1 of the relay KA1 is connected in parallel across the closing switch SB1. The integrated controller JZK1 is provided with a control input terminal and a control common terminal. The control input terminal includes a start / stop control terminal, which is connected to one end of the normally open contact KA1-2 of relay KA1, and the other end of the normally open contact KA1-2 of relay KA1 is connected to the control common terminal. The two power supply input terminals of the integrated controller JZK1 are respectively connected to the two ends of the secondary side of transformer TC.

2. The mining explosion-proof and intrinsically safe low-voltage contactless switch circuit as described in claim 1, characterized in that, The control circuit also includes an electrical interlock contact KB1; the electrical interlock contact KB1 is connected in series in the control circuit.

3. The mining explosion-proof and intrinsically safe low-voltage contactless switch circuit as described in claim 1, characterized in that, The integrated controller JZK1 also includes a confirmation input terminal, a reset input terminal, and a shift input terminal. The confirmation input terminal is connected to one end of the confirmation button QR, and the other end of the confirmation button QR is connected to the common control terminal. The reset input terminal is connected to one end of the reset button FW, and the other end of the reset button FW is connected to the common control terminal. The shift input terminal is connected to one end of the shift button YW, and the other end of the shift button YW is connected to the common control terminal. The integrated controller JZK1 is also equipped with a display screen.

4. The mining explosion-proof and intrinsically safe low-voltage contactless switch circuit as described in claim 1, characterized in that, The control input terminals on the integrated controller JZK1 also include a gas alarm input terminal and a fan alarm input terminal; the gas alarm input terminal is connected to one end of the normally open contact WS of the gas sensor, and the other end of the normally open contact WS of the gas sensor is connected to the control common terminal; the fan alarm input terminal is connected to one end of the normally open contact FD of the fan fault detection, and the other end of the normally open contact FD of the fan fault detection is connected to the control common terminal.

5. The mining explosion-proof and intrinsically safe low-voltage contactless switch circuit as described in claim 1, characterized in that, The integrated controller JZK1 also includes a communication port for communicating with a host computer.

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