Motor automatic stop control device for hydraulic station of intermediate frequency furnace

Abstract

The utility model discloses a kind of hydraulic station motor automatic stop control device for intermediate frequency furnace, including travel switch SQ1 installed on furnace frame, the normally open contact of travel switch SQ1 is accessed in control circuit, and when furnace body returns to position, travel switch SQ1 and furnace body contact form closed state;The normally closed contact one end of intermediate relay in control circuit is connected power line, the other end is connected the control coil wiring end of alternating current contactor, the incoming line of the main contact input end of alternating current contactor KM1 is respectively connected three-phase power line, and main contact output end connects the power connector of hydraulic motor.The utility model is automatically controlled, and the security and automation level of control system are improved;Realize that hydraulic station motor is automatically stopped after returning, and energy-saving effect is obvious.

Description

Technical Field

[0001] This utility model relates to an automatic shutdown control device for a hydraulic station motor used in a medium-frequency furnace, belonging to the technical field of medium-frequency furnace control equipment. Background Technology

[0002] Currently, most medium-frequency furnaces use steel structures for their bodies, with high-power furnaces employing hydraulic control for tilting and unloading. The hydraulic tilting control involves first starting the hydraulic station motor, then controlling manual or solenoid valves to tilt and return the furnace to its original position. Because operators often have many tasks on the furnace platform, they frequently forget to stop the hydraulic station motor after the furnace has returned to its original position. The long time between tilting and restarting results in considerable power consumption from the high-power motor. Furthermore, prolonged operation of the hydraulic pump causes the hydraulic oil temperature to rise and become thinner, which can lead to insufficient oil pressure and affect tilting. Therefore, a control device for medium-frequency furnaces is needed that can automatically stop the hydraulic station motor after it returns to its original position.

[0003] Our research revealed that existing technologies for controlling medium-frequency furnaces primarily focus on the furnace itself, including temperature, cooling water, and leak detection. For example, the medium-frequency furnace control circuit disclosed in CN201420233551.8 does not include a control device for the hydraulic station motor. Instead, it involves the control of the hydraulic motor, such as the automatic start-stop control circuit and method for the hydraulic motor disclosed in CN201711332113.1. This method uses a series connection between a normally open low-level detection switch and a normally closed high-level detection switch to control an AC contactor coil, along with an auxiliary normally open switch connected in parallel to the low-level switch, to achieve automatic start-stop logic triggered by the liquid level. An energy storage device is used to maintain the liquid level decrease, extending downtime and reducing ineffective operation. However, this control circuit and method cannot be used for the automatic shutdown of the hydraulic station motor in a medium-frequency furnace after it returns to its original position. Utility Model Content

[0004] Based on the customer's technical requirements and in view of the above-mentioned problems existing in the existing technology, our company organized R&D personnel to tackle the problems and finally provided an automatic shutdown control device for the hydraulic station motor of medium frequency furnace.

[0005] The purpose of this utility model is to solve the above-mentioned problems in the prior art and provide an automatic shutdown control device for a hydraulic station motor of a medium-frequency furnace. The device includes a limit switch SQ1 installed on the furnace frame. The normally open contact of the limit switch SQ1 is connected to the control circuit, and when the furnace body returns to its position, the limit switch SQ1 contacts the furnace body to form a closed state. One end of the normally closed contact of the intermediate relay in the control circuit is connected to the power line, and the other end is connected to the control coil terminal of the AC contactor. The input terminals of the main contacts of the AC contactor KM1 are respectively connected to the input lines of the three-phase power lines, and the output terminals of the main contacts are connected to the power connector of the hydraulic motor.

[0006] Furthermore, two intermediate relays are used, namely intermediate relay J1 and intermediate relay KA1, and the control coil voltages of the two intermediate relays are different.

[0007] This utility model utilizes the fact that when the furnace body returns to its position, it drives the limit switch to close, causing the control circuit to operate, which in turn drives the intermediate relay J1 to operate, then drives the intermediate relay KA1 to operate, and then drives the AC contactor KM1 to operate. The normally closed contact of the AC contactor KM1 opens, which de-energizes the coil of the AC contactor controlling the motor, causing its main contacts to open and the motor to stop.

[0008] Furthermore, the normally closed contact of the intermediate relay KA1 is connected in series with the control coil terminal of the AC contactor KM1, and the start button SB1, the stop button SB2, and the thermal overload protector FR1 are connected in parallel. The stop button SB2 is connected in parallel with the normally open button of the AC relay KM1.

[0009] Furthermore, the main contact input terminals of the AC contactor KM1 are respectively connected to one end of the fuse on the corresponding line, and the other end of the fuse is connected to the circuit breaker, which is connected to the three-phase power supply line.

[0010] Furthermore, the control circuit includes a transformer primary coil connected to two power supply live wires, a transformer secondary coil connected to the input of a rectifier bridge, one output of the rectifier bridge grounded, and the other output connected to one end of resistor R1 and the positive terminal of polarized capacitor EC1. The other end of resistor R1 is connected to the positive terminal of polarized capacitor EC2 and the input pin of voltage regulator module U1. The negative terminals of polarized capacitors EC1 and EC2 are grounded, the grounding pin of voltage regulator module U1 is grounded, and the output pin of voltage regulator module U1 is connected to the positive terminal of polarized capacitor EC3, one end of capacitor C1, the positive terminal of LED1, and one end of limit switch SQ1. The negative terminal of polarized capacitor EC3 and the other end of capacitor C1 are grounded, and the negative terminal of LED1 is... One end of the circuit is grounded through resistor R7. The other end of the limit switch SQ1 is connected to one end of resistor R2. The other end of resistor R2 is connected to the terminal of the control coil of intermediate relay J1, the cathode of diode D2, the positive terminal of polarized capacitor EC4, and one end of resistor R3. The negative terminal of polarized capacitor EC4 and the other end of resistor R3 are connected to the base of transistor Q1 and one end of resistor R4. The other end of resistor R4 and the emitter of transistor Q1 are grounded. The collector of transistor Q1 is connected to the anode of diode D2 and the other terminal of the control coil of intermediate relay J1. One side of the normally open terminal of intermediate relay J1 is connected to the output terminal of the rectifier bridge, and the other side is connected to one end of the control coil of intermediate relay KA1. The other end of the control coil of intermediate relay KA1 is grounded.

[0011] Furthermore, two operation indicator lights are connected between the output terminal of the rectifier bridge and ground. One of them is the normally open auxiliary contact of the AC relay and the working indicator light I, and the other is the normally closed auxiliary contact of the AC relay and the working indicator light II.

[0012] The advantages of this utility model over the prior art are as follows: 1. The entire process is completed automatically, improving the safety and automation level of the control system; 2. The hydraulic station motor automatically stops after returning to its original position, resulting in significant energy savings. Attached Figure Description

[0013] Figure 1 This is a circuit connection diagram of an embodiment of the present utility model; Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments. Example

[0015] like Figure 1 The device shown is an automatic shutdown control device for a hydraulic station motor in a medium-frequency furnace. QF is a circuit breaker, FU1 to FU4 are fuses, KM1 is an AC contactor, FR1 is a thermal overload protector, and M1 is a motor.

[0016] After QF is closed, the AC 18V voltage of transformer T1 is rectified by rectifier bridge D1 to output +24V voltage, which powers the working indicator lights I, II and KA1 coil.

[0017] The +24V voltage is then passed through resistors R1 and R2 to charge the polarized capacitor EC4. The voltage is then regulated by the voltage regulator module U1 (MC7815), filtered, and output as a +15V voltage. LED1 is the +15V indicator light, and SQ1 is the normally open contact of the limit switch. When the furnace body returns to its original position, SQ1 becomes closed.

[0018] At the moment QF closes, the +15V voltage passes through SQ1, resistor R2, and polarized capacitor EC4, turning on transistor Q1. Because the voltage across polarized capacitor EC4 cannot change abruptly, the base voltage of transistor Q1 increases, causing Q1 to conduct. This energizes intermediate relay J1, which in turn energizes intermediate relay KA1, causing the KA1-1 contact to open. However, because the charging time of polarized capacitor EC4 is very short, the voltage drop across resistor R2 is insufficient to turn on transistor Q1. Therefore, transistor Q1 returns to the off state, and the normally closed contact of KA1-1 closes again, without affecting the normal starting of motor M1.

[0019] When AC contactor KM1 is energized and engaged, motor M1 starts normally, driving the oil pump to work. The furnace is tilted through the manual valve or solenoid valve, limit switch SQ1 is disconnected, transistor Q1 is in the off state, polarized capacitor EC4 discharges through resistor R3 to prepare for the next charge, KA1-1 normally closed contact closes, and motor M1 works normally.

[0020] After the furnace tilting operation is completed, the furnace body returns to its normal position. The normally open contact of the limit switch SQ1 closes, the transistor Q1 turns on, the intermediate relay J1 is energized, causing the intermediate relay KA1 to energize, the normally closed contact of KA1-1 to open, the AC contactor KM1 is de-energized, the main contacts of KM1 open, and the motor M1 stops. There is no need for manual intervention to stop the motor M1, avoiding problems caused by forgetting to stop the hydraulic station motor.

[0021] At this time, the polarized capacitor EC4 continues to discharge through resistor R3, ensuring that transistor Q1 is reliably turned on, and the intermediate relay KA1 remains energized, ensuring that AC contactor KM1 is completely de-energized, thus reliably stopping motor M1. Once the polarized capacitor EC4 has completely discharged, transistor Q1 automatically turns off, intermediate relay KA1 releases, KA1-1 resets and closes, and the system returns to its initial standby state, awaiting the next start operation. The entire process is completed automatically, improving the safety and automation level of the control system.

[0022] The above embodiments are merely explanations and illustrations of the technical solution of this utility model and should not be used to limit the protection scope of the technical solution of this utility model. All simple modifications based on this solution are within the protection scope of this utility model.

Claims

1. An automatic shutdown control device for a hydraulic station motor used in a medium-frequency furnace, characterized in that: This includes a limit switch SQ1 installed on the furnace frame. The normally open contact of the limit switch SQ1 is connected to the control circuit, and when the furnace body returns to its position, the limit switch SQ1 contacts the furnace body to form a closed state. One end of the normally closed contact of the intermediate relay in the control circuit is connected to the power line, and the other end is connected to the control coil terminal of the AC contactor. The main contact input terminal of the AC contactor KM1 is connected to the input of the three-phase power line, and the main contact output terminal is connected to the power connector of the hydraulic motor.

2. The automatic shutdown control device for the hydraulic station motor of the medium-frequency furnace according to claim 1, characterized in that: Two intermediate relays are used, namely intermediate relay J1 and intermediate relay KA1, and the control coil voltages of the two intermediate relays are different.

3. The automatic shutdown control device for the hydraulic station motor of the medium-frequency furnace according to claim 1, characterized in that: The normally closed contact of the intermediate relay KA1 is connected in series with the control coil terminal of the AC contactor KM1. The start button SB1, the stop button SB2, and the thermal overload protector FR1 are connected in series. The stop button SB2 is connected in parallel with the normally open button of the AC relay KM1.

4. The automatic shutdown control device for the hydraulic station motor of the medium-frequency furnace according to claim 1, characterized in that: The main contact input terminals of the AC contactor KM1 are respectively connected to one end of the fuse on the line, and the other end of the fuse is connected to the circuit breaker, which is connected to the three-phase power supply line.

5. The automatic shutdown control device for the hydraulic station motor of the medium-frequency furnace according to claim 1, characterized in that: The control circuit includes a transformer primary coil connected to two power supply wires. The transformer secondary coil is connected to the input of a rectifier bridge. One output of the rectifier bridge is grounded, and the other output is connected to one end of resistor R1 and the positive terminal of polarized capacitor EC1. The other end of resistor R1 is connected to the positive terminal of polarized capacitor EC2 and the input pin of voltage regulator module U1. The negative terminals of polarized capacitors EC1 and EC2 are grounded. The grounding pin of voltage regulator module U1 is grounded. The output pin of voltage regulator module U1 is connected to the positive terminal of polarized capacitor EC3, one end of capacitor C1, the positive terminal of LED1, and one end of limit switch SQ1. The negative terminal of polarized capacitor EC3 and the other end of capacitor C1 are grounded. The negative terminal of LED1 is connected to... The circuit is connected to ground via resistor R7. The other end of the limit switch SQ1 is connected to one end of resistor R2. The other end of resistor R2 is connected to the control coil terminal of intermediate relay J1, the cathode of diode D2, the positive terminal of polarized capacitor EC4, and one end of resistor R3. The negative terminal of polarized capacitor EC4 and the other end of resistor R3 are connected to the base of transistor Q1 and one end of resistor R4. The other end of resistor R4 and the emitter of transistor Q1 are grounded. The collector of transistor Q1 is connected to the anode of diode D2 and the other terminal of the control coil of intermediate relay J1. One side of the normally open terminal of intermediate relay J1 is connected to the output terminal of the rectifier bridge, and the other side is connected to one end of the control coil of intermediate relay KA1. The other end of the control coil of intermediate relay KA1 is grounded.

6. The automatic shutdown control device for the hydraulic station motor of the medium-frequency furnace according to claim 5, characterized in that: Two operation indicator lights are also connected between the output terminal of the rectifier bridge and ground. One of them is the normally open auxiliary contact of the AC relay and the working indicator light I, and the other is the normally closed auxiliary contact of the AC relay and the working indicator light II.

Images