CN214480525U

CN214480525U - Power-off arc extinguishing circuit for electromagnetic slurry magnetic separator

Info

Publication number: CN214480525U
Application number: CN202120783763.3U
Authority: CN
Inventors: 马长君; 柳晓明; 赵富红; 刘世昌; 丁长田; 马晓永
Original assignee: Shandong Huate Magnet Technology Co Ltd
Current assignee: Shandong Huate Magnet Technology Co Ltd
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-10-22
Anticipated expiration: 2031-04-16

Abstract

The utility model discloses a power failure arc extinguishing circuit for an electromagnetic slurry magnetic separator, which belongs to the technical field of power supply rectifying devices and comprises a three-phase alternating current power supply, a three-phase isolation transformer, a three-phase alternating current circuit breaker, a three-phase alternating current contactor, a first three-phase rectifying bridge group, a shunt, an electromagnetic coil and a second three-phase rectifying bridge group which are coupled in sequence; the three-phase isolation transformer is coupled with a first relay and a switching power supply; a plate resistor is coupled between the first three-phase rectifier bridge group and the second three-phase rectifier bridge group, and a freewheeling diode is coupled between the plate resistor and the electromagnetic coil; the utility model discloses can enough ensure the excitation of charging, the demagnetization speed of discharging under the electric wire netting normal operation, can protect other components and parts that link to each other with three-phase ac contactor not by overvoltage damage under the electric wire netting sudden stop condition again, improve the work efficiency and the use reliability of electromagnetic paste magnet separator, have advantages such as job stabilization is reliable, interference immunity is strong, rational in infrastructure, adaptability is good and convenient operation.

Description

Power-off arc extinguishing circuit for electromagnetic slurry magnetic separator

Technical Field

The utility model relates to a power rectifier technical field, concretely relates to electromagnetism thick liquids magnet separator is with arc extinguishing circuit that has a power failure.

Background

The electromagnetic slurry magnetic separator is a device for effectively purifying weak magnetic impurities in nonmetallic minerals by using electromagnetic force applied to the mineral processing industry, and mainly comprises a magnetic system assembly, three groups of electromagnetic coils connected in parallel, a rectification power supply system, a water circulation cooling device and the like, wherein the working power supply of the electromagnetic coils is a direct-current discontinuous power supply. The direct current discontinuous power supply is a direct current power supply with adjustable duty ratio and amplitude which is generated under the closed-loop control method of a rectification power supply. When the electromagnetic coil flows in the direct current with adjustable duty ratio and amplitude, the direct current magnetic field with adjustable duty ratio and amplitude can be generated. When a direct-current magnetic field exists, the nonmetallic minerals with the weak magnetic impurities pass through the cavity of the electromagnetic slurry magnetic separator, the weak magnetic impurities can be adsorbed in the magnetic medium, and the high-purity nonmetallic minerals flow out of the cavity to be purified. When the direct-current magnetic field disappears, the non-metallic minerals with the weak magnetic impurities stop entering the cavity of the electromagnetic slurry magnetic separator, and the weak magnetic impurities in the cavity can be washed out by using high-pressure water to form a working cycle. The electromagnetic slurry magnetic separator operates periodically according to the above described duty cycle.

The traditional direct current discontinuous power supply for the electromagnetic slurry magnetic separator comprises a transformer, a three-phase alternating current circuit breaker, a three-phase alternating current contactor, a three-phase rectifier bridge, a fly-wheel diode, a plate resistor, a resistance-capacitance protection circuit and the like. When the rectifier bridge works, a power grid power supply is firstly switched on by the three-phase alternating current circuit breaker and then flows into the three-phase alternating current contactor, the three-phase alternating current contactor is closed and then enters the three-phase rectifier bridge, the three-phase alternating current contactor is rectified by the rectifier bridge to obtain a direct current power supply, and the direct current power supply acts on the electromagnetic coil to generate a stable direct current magnetic field. When the rectifier bridge stops working, the electric energy stored in the electromagnetic coil forms a loop through the freewheeling diode connected with the plate resistor in series, and the rapid discharge demagnetization is realized through the resistance heating and active inversion modes of the electromagnetic coil, so that the weak magnetic impurities in the cavity are cleaned by the high-pressure water.

Because the electromagnetic coil in the electromagnetic slurry magnetic separator has the characteristics of more parallel turns, large inductance, high excitation power and the like, when the large inductance coil is electrified and magnetized, the three-phase alternating current contactor is in a connected state, and electric energy is transmitted to the side of the rectifier; when the electromagnetic coil is in excitation operation, the power grid suddenly cuts off power to cause the three-phase alternating current contactor to trip out and draw an arc, and the instantaneous high voltage that the arc can produce can puncture other electronic components in the control cabinet sometimes, directly influences the service life of the equipment control cabinet, can lead to the electromagnetic slurry magnetic separator control system to work normally when serious.

For solving above-mentioned problem, ensure that electromagnetic paste magnet separator can demagnetization fast after the separation is finished, under the prerequisite of guaranteeing high efficiency operation, prolong electromagnetic paste magnet separator switch board's life, prior art adopts following method to handle usually:

(1) a three-phase solid-state contactor is used instead of a three-phase ordinary contactor. The three-phase solid-state contactor is additionally arranged between the three-phase alternating-current circuit breaker and the rectifier bridge, and the method has the advantages of simple structure, easiness in implementation and short development period. However, the three-phase solid-state contactor is easy to be damaged by overvoltage breakdown when the three-phase alternating-current circuit breaker trips, the outsourcing cost of the high-power three-phase solid-state contactor is high, the installation size is large, the assembly space of the equipment control cabinet can be increased, and the overall manufacturing cost of the equipment is increased.

(2) The three-phase AC contactor is directly removed from the control circuit. The mode that the three-phase alternating current circuit breaker is directly connected with the rectifier bridge is adopted, so that the phenomenon that the contactor suddenly jumps out and arcs when the power grid suddenly cuts off in the excitation work of the electromagnetic slurry magnetic separator control cabinet can be avoided. However, when a user needs to disconnect a power supply under an emergency condition in the using process, an operator needs to manually disconnect the three-phase alternating-current circuit breaker, and the problems that the personal safety of the operator is endangered, the power failure is not timely, the DCS centralized control cannot be realized and the like exist.

(3) And a UPS power supply is adopted to supply power to the coil of the AC contactor independently. The method can avoid the condition that the three-phase alternating current contactor is damaged by arc discharge when the power grid is interrupted in the process of excitation of the electromagnetic coil. However, the energy storage device in the UPS power supply has limited service life, needs to be replaced regularly, and has high maintenance cost; moreover, when the UPS fails, the three-phase AC contactor stops, and the system failure point is increased.

(4) The mode of connecting the coils of the electromagnetic slurry magnetic separator with the freewheeling diode in an anti-parallel mode is adopted. When the direct current bus is connected with the freewheeling diode in an anti-parallel mode, a discharging loop can be formed when the coil discharges, and the bus potential is clamped between 0.3V and 0.7V, so that the method can prevent the power grid power failure rectifier from entering an inversion state when the electromagnetic coil of the electromagnetic slurry magnetic separator is excited, and an arc discharge phenomenon cannot be generated when the contactor is disconnected. But the problem of low demagnetization discharge speed exists, and the working efficiency of equipment can be reduced; demagnetization discharge is consumed by self heating of the coil, and energy waste is caused.

Therefore, designing a circuit which is safe, controllable and reliable, can rapidly discharge and demagnetize and can adapt to mutation is an urgent problem to be solved in the industry.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides a pair of power failure arc extinguishing circuit for electromagnetic paste magnet separator ensures that electromagnetic paste magnet separator can effectually avoid drawing the appearance of the condition of arc damage because of the three-phase ac contactor that the electric wire netting suddenly stopped causing under can demagnetization prerequisite fast to have advantages such as job stabilization, safe and reliable, interference immunity are strong, rational in infrastructure, economical and practical, adaptability are good and convenient operation.

In order to realize the purpose, the utility model discloses a technical scheme as follows:

a power failure arc extinguishing circuit for an electromagnetic slurry magnetic separator comprises a three-phase alternating current power supply, a three-phase isolation transformer, a three-phase alternating current breaker, a three-phase alternating current contactor, a first three-phase rectifier bridge group, a shunt, an electromagnetic coil and a second three-phase rectifier bridge group which are coupled in sequence; the second three-phase rectifier bridge group is coupled with the three-phase alternating current contactor; one phase of the secondary side of the three-phase isolation transformer is coupled with a first relay and a switching power supply; and a plate resistor is coupled between the first three-phase rectifier bridge group and the second three-phase rectifier bridge group, and a freewheeling diode is coupled between the plate resistor and the electromagnetic coil.

As a preferred technical solution, the shunt is coupled with a shunt signal conditioning circuit, the shunt signal conditioning circuit is coupled with a PID controller, and the PID controller is respectively coupled with the first three-phase rectifier bridge group and the second three-phase rectifier bridge group.

As a preferred technical solution, the first three-phase rectifier bridge group and the second three-phase rectifier bridge group are both connected in parallel with a resistance-capacitance protection circuit, and the resistance-capacitance protection circuit includes a resistor and a capacitor connected in series.

As a preferred technical solution, a three-phase fast fuse is coupled between the three-phase ac contactor and the first three-phase rectifier bridge group.

In a preferred embodiment, the plate resistors are three and are connected in series in sequence.

As a preferred technical solution, the plate-type resistor is coupled with a freewheeling silicon, and a gate of the freewheeling silicon is sequentially coupled with a current-limiting resistor, a second relay and a direct-current voltage source; the second relay is connected with the positive electrode of the direct current voltage source, and the cathode of the follow current silicon controlled rectifier is connected with the negative electrode of the direct current voltage source.

As a preferable technical solution, a power supply capacitor is coupled to the three-phase ac contactor, the power supply capacitor is coupled to the dc voltage source, and an emergency stop button is provided between the power supply capacitor and the three-phase ac contactor.

The utility model has the advantages of that:

the utility model discloses can enough ensure the excitation of charging, the demagnetization speed of discharging under the electric wire netting normal operation, can protect other components and parts that link to each other with three-phase ac contactor not by the excessive pressure damage under the electric wire netting sudden stop condition again, improve the work efficiency and the use reliability of electromagnetic paste magnet separator, reduce the wasting of resources, have advantages such as job stabilization is reliable, interference immunity is strong, rational in infrastructure, adaptability is good and convenient operation.

Drawings

FIG. 1 is a circuit topology structure diagram of a power failure arc extinguishing circuit for an electromagnetic slurry magnetic separator according to the present invention;

FIG. 2 is a schematic diagram of the rectification and inversion intervals of the current in the power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator of the present invention;

fig. 3 is the utility model relates to an action chronologic diagram of three-phase ac contactor and first relay and power supply capacitance's charge-discharge amplitude timing diagram in power failure arc extinguishing circuit for electromagnetic paste magnet separator.

Detailed Description

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1-3, an embodiment of a power failure arc extinguishing circuit for an electromagnetic slurry magnetic separator according to the present invention includes a three-phase ac power source (R, S, T), a three-phase isolation transformer (T1), a three-phase ac circuit breaker (Q1), a three-phase ac contactor (K1), a first three-phase rectifier bridge group (VT1, VT2, VT3), a shunt (FL), an electromagnetic coil (Z1), and a second three-phase rectifier bridge group (VT4, VT5, VT 6); the second three-phase rectifier bridge group (VT4, VT5, VT6) is coupled with the three-phase alternating current contactor (K1); one phase of the secondary side of the three-phase isolation transformer (T1) is coupled with a first relay (K2) and a switching power supply (AC/DC); plate-type resistors (R7, R8 and R9) are coupled between the first three-phase rectifier bridge group (VT1, VT2 and VT3) and the second three-phase rectifier bridge group (VT4, VT5 and VT6), a freewheeling diode (VD1) is coupled between the plate-type resistors and the electromagnetic coil, and a series circuit of the plate-type resistors (R7, R8 and R9) and the freewheeling diode (VD1) is used for raising the bus potential when the electromagnetic coil (Z1) discharges, so that the inverter condition is formed to accelerate the discharge.

Please refer to fig. 1, the three-phase isolation transformer (T1) transmits power and isolates high-frequency harmonics in the three-phase ac power supply (R, S, T) to ensure power quality; the secondary side W phase and the neutral point of the three-phase isolation transformer (T1) are respectively connected with the two ends of a first relay (K2) and a switching power supply (AC/DC), and the first relay (K2) provides a rear-stage circuit whether an electric signal exists in a power grid or not; specifically, the first relay (K2) only provides a switching signal, so that a microminiature relay is selected, and a switching power supply (AC/DC) provides a direct-current 24V voltage source for a rear-stage circuit; the three-phase alternating current circuit breaker (Q1) is used for controlling the on-off between the three-phase alternating current power supply (R, S, T) and the lower-stage component; the three-phase alternating current contactor (K1) is used for controlling the on-off between the three-phase alternating current power supply (R, S, T) and the lower-level component, and plays a role in safely breaking the power supply.

Specifically, the current sampling circuit is used for carrying out signal isolation sampling, proportion amplification and signal conversion on signals at two ends of the current divider (FL), then sending the signals into the PLC analog quantity module for PID operation, and outputting current signals to the trigger unit so as to accurately adjust the current output value of the current divider (FL); further, the PID controller is respectively coupled with the first three-phase rectifier bridge group (VT1, VT2, VT3) and the second three-phase rectifier bridge group (VT4, VT5, VT6), the first three-phase rectifier bridge group (VT1, VT2, VT3) and the second three-phase rectifier bridge group (VT4, VT5, VT6) all adopt a three-phase fully-controlled bridge rectifier circuit form, specifically, the trigger units all adopt single narrow 12 pulse form output, the three-phase alternating current power supply can be rectified into a direct current power supply, and the amplitude value and the duty ratio switching signal of the direct current power supply can be controlled by a PLC analog quantity module. Specifically, referring to fig. 2, when the electromagnetic coil (Z1) needs to be energized and magnetized, because the pulse sending angle of the trigger unit is in a linear inverse proportion relation with the given voltage signal of the trigger unit, when the given trigger unit is 20MA, the pulse angle is 0 °, when the given trigger unit is 4MA, the pulse angle is 180 °, at this time, the PLC analog module outputs a DC12-20MA signal to the trigger unit, the pulse of the trigger unit works in a rectification area (0-90 °), the actual sampling value quickly follows the user setting value, and quick and accurate magnetization is realized. When the electromagnetic coil (Z1) discharges and demagnetizes, the PLC analog quantity module is controlled to output a DC4-12MA signal to the trigger unit, the pulse of the trigger unit is enabled to work in an active inversion region (90-180 degrees), when the trigger angle works in 90-180 degrees, the electromagnetic coil can generate counter electromotive force, the internal energy of the electromagnetic coil (Z1) is actively inverted into an alternating current side power grid from the negative electrode of the electromagnetic coil (Z1) through a rectifier bridge, and the demagnetization time is saved and the working efficiency of the equipment is improved by adopting an active inversion discharge demagnetization method.

In practical use, when a current passes through the current divider (FL), the current divider (FL) generates a 0-75MV dc signal according to the magnitude of the current value, the 0-75MV dc signal is converted into a linear 4-20MA current signal through the amplifier and the current output chip, and the 4-20MA current signal is input into the analog channel of the PID controller; specifically, the model of the current output chip may be XTR 111.

In this embodiment, referring to fig. 3, when a power grid is subjected to a brown-out at t0-t2, the first relay (K2) is pulled in at time t0, the three-phase ac contactor (K1) is pulled in at time t1, the voltage of the power supply capacitor (C8) is not charged to 24V, the power-down interval time of the first relay (K2) and the three-phase ac contactor (K1) is short at time t2, but the electromagnetic coil (Z1) does not have electric energy at this time, and the three-phase ac contactor (K1) does not have a situation that an arc is burned out. When the power grid is normal and starts to work normally (t3-t4), the three-phase alternating current contactor (K1) begins to be closed, the first relay (K2) is connected, and the follow current silicon controlled rectifier (VT7) cannot be triggered.

In this embodiment, referring to fig. 1, the first three-phase rectifier bridge group (VT1, VT2, VT3) and the second three-phase rectifier bridge group (VT4, VT5, VT6) are composed of six thyristors, each thyristor has a series-connected resistor (R1, R2, R3, R4, R5, R6) and capacitor (C2, C3, C4, C5, C6, C7) in parallel, and the thyristors can be protected from being broken down by abrupt voltage at the moment of turning on and off.

In this embodiment, referring to fig. 1, a three-phase fast fuse (RSF) is coupled between the three-phase ac contactor (K1) and the first three-phase rectifier bridge group (VT1, VT2, VT3), and the three-phase fast fuse (RSF) can achieve the purpose of quickly cutting off a circuit in case of an overload or a short circuit.

In this embodiment, referring to fig. 1, three plate resistors (R7, R8, R9) are sequentially connected in series, the plate resistors (R7, R8, R9) are coupled with a freewheeling silicon controlled rectifier (VT7), and a gate of the freewheeling silicon controlled rectifier (VT7) is sequentially coupled with a current-limiting resistor (R10), a second relay (K3) and a dc voltage source; the second relay (K3) is connected with the positive pole of the direct-current voltage source, and the cathode of the follow-current silicon controlled rectifier (VT7) is connected with the negative pole of the direct-current voltage source; and a follow current controlled silicon (VT7) connected with the plate-type resistors (R7, R8 and R9) in parallel is used for clamping the bus potential at the moment of power failure, preventing the bus potential from entering an inversion state and protecting a three-phase alternating current contactor (K1).

In this embodiment, referring to fig. 1, a power supply capacitor (C8) is coupled to the three-phase ac contactor, the power supply capacitor (C8) is coupled to a dc voltage source, an emergency stop button (SB0) is disposed between the power supply capacitor (C8) and the three-phase ac contactor (K1), the dc voltage source supplies power to the power supply capacitor (C8), and the power supply capacitor (C8) supplies power to the three-phase ac contactor (K1) through the emergency stop button (SB0), so that the three-phase ac contactor (K1) can be tripped again by 2-3S when the three-phase ac power supply (R, S, T) is momentarily stopped.

The utility model discloses a concrete working method as follows:

referring to fig. 1-3, when the electromagnetic coil (Z1) is energized and magnetized, the freewheeling thyristor (VT7) does not operate, the PLC analog module brings the working current set by the user and the actual current sampling value into PID operation, the PLC analog module outputs a current signal of a proper magnitude to the trigger unit to precisely adjust the current output value, so that the current can reach the given current value at the fastest speed and be stably output, and the electromagnetic slurry magnetic separator generates a stable magnetic field for separating impurities. When the electromagnetic coil (Z1) is demagnetized and discharged, the follow current silicon controlled rectifier (VT7) does not work, the two ends of the electromagnetic coil (Z1) can generate counter electromotive force, and the PLC analog quantity module controls the trigger unit to move backwards by a pulse output angle so as to ensure that the first three-phase rectifier bridge group (VT1, VT2 and VT3) and the second three-phase rectifier bridge group (VT4, VT5 and VT6) can work under the active inversion condition. When the three-phase alternating current power supply (R, S, T) stops instantaneously, the follow current silicon controlled rectifier (VT7) works, the bus potential is clamped, the residual electric energy of the electromagnetic coil (Z1) is released through the self resistance loop, and the three-phase alternating current contactor (K1) is released again at the moment, so that the problem that the contact is damaged by instantaneous arc discharge is avoided.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A power failure arc extinguishing circuit for an electromagnetic slurry magnetic separator is characterized by comprising a three-phase alternating current power supply, a three-phase isolation transformer, a three-phase alternating current breaker, a three-phase alternating current contactor, a first three-phase rectifier bridge group, a shunt, an electromagnetic coil and a second three-phase rectifier bridge group which are coupled in sequence; the second three-phase rectifier bridge group is coupled with the three-phase alternating current contactor; one phase of the secondary side of the three-phase isolation transformer is coupled with a first relay and a switching power supply; and a plate resistor is coupled between the first three-phase rectifier bridge group and the second three-phase rectifier bridge group, and a freewheeling diode is coupled between the plate resistor and the electromagnetic coil.

2. The power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator as claimed in claim 1, wherein the shunt is coupled with a shunt signal conditioning circuit, the shunt signal conditioning circuit is coupled with a PID controller, and the PID controller is respectively coupled with the first three-phase rectifier bridge group and the second three-phase rectifier bridge group.

3. The power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator as claimed in claim 1, wherein the first three-phase rectifier bridge group and the second three-phase rectifier bridge group are connected in parallel with a resistance-capacitance protection circuit, and the resistance-capacitance protection circuit comprises a resistor and a capacitor which are connected in series.

4. The power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator as claimed in claim 1, wherein a three-phase fast fuse is coupled between the three-phase ac contactor and the first three-phase rectifier bridge group.

5. The power failure arc extinguishing circuit for the electromagnetic paste magnetic separator as claimed in claim 1, wherein the plate resistors are three and are connected in series.

6. The power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator according to claim 1 or 5, wherein a follow current silicon controlled rectifier is coupled to the plate resistor, and a gate pole of the follow current silicon controlled rectifier is sequentially coupled with a current limiting resistor, a second relay and a direct current voltage source; the second relay is connected with the positive electrode of the direct current voltage source, and the cathode of the follow current silicon controlled rectifier is connected with the negative electrode of the direct current voltage source.

7. The power failure arc extinguishing circuit for the electromagnetic slurry magnetic separator as claimed in claim 6, wherein a power supply capacitor is coupled to the three-phase ac contactor, the power supply capacitor is coupled to the dc voltage source, and an emergency stop button is provided between the power supply capacitor and the three-phase ac contactor.