Research and Application of Electromagnetic Speed ​​Regulating Electrical Haulage Shearer

China from the late 1980s began to study AC variable speed electric traction coal mining machine, in the early 1990s research prototype successfully. For more than 10 years, a lot of research has been done on the series design, control system and function improvement of shearer, and a series of AC variable frequency electric traction shearer has been developed, which has been gradually promoted and used in domestic coal mines. In recent years, while the development of AC variable frequency speed control electric traction shearer, the research of switched reluctance speed regulation and electromagnetic speed governing electric traction shearer has been carried out, which has played a great role in the development of electric traction shearer in China. enhancement.

1 electromagnetic speed control electric traction shearer

In recent years, China's airborne variable frequency speed control AC traction shearer has made great progress. Due to the working characteristics of coal mining machines and the specific conditions of coal enterprises in China, electric traction shearers still have a large gap compared with foreign coal enterprises in terms of total production and scope of use. Electromagnetic speed regulation technology is a mature technology. Because of its simple structure, reliable use, good starting performance and large starting torque, it has been successfully applied in other industries. By further studying the electromagnetic speed regulation technology, the speed control performance is changed by modern technology, making it suitable for the shearer's traction, and the advantages of electromagnetic speed regulation are applied to the shearer, and a simple structure, easy maintenance and manufacture are developed. The electromagnetic speed-regulating electric haulage shearer with low cost, large traction power and large starting torque will greatly promote the promotion of electric traction shearer in China.

Although the electromagnetic speed regulating motor (Fig. 1) is a speed regulating device with the advantages of simple structure, convenient processing, reliable use, good starting performance and large starting torque, the electromagnetic speed regulating motor should be used as the shearing power of the shearer. Still need further research.  Figure 1 Flameproof electromagnetic speed control motor

In recent years, the electromagnetic speed regulating motor made by using new materials and new methods can increase the efficiency by 10%; the maximum output speed can reach about 95% of the asynchronous motor speed. The speed measurement of the speed regulating motor is carried out by a speed measuring generator. The performance is poor at low speed, and then converted to the control loop, so that the low speed performance output of the electromagnetic speed regulating motor is unstable. In order to solve this problem, in the electromagnetic speed regulating motor used by the shearer, a shaft encoder is used to measure the speed of the speed regulating motor, the speed measurement is digitized, the measurement accuracy is improved, and the speed signal is directly sent to the computer. Processing, low speed performance has been fundamentally improved.

In the research and practical work of electromagnetic speed-regulating motors, improving the adjustment accuracy is a key point. Studies have shown that, unlike other governor devices, its adjustment accuracy depends on the accuracy of the artificially designed current controller and the choice of control method. After using computer control and improving the accuracy of the current controller, we can completely solve the problem of accuracy and stability of low current output.

2 electromagnetic speed control electric traction coal mining machine computer speed control system

In order to make the adjustment effect more ideal, the speed control system of the electromagnetic speed control electric traction shearer adopts the speed and current double closed loop speed control system (Fig. 2), and adopts computer control to make the system more perfect. If only the speed adjustment is adopted, the disturbance caused by the grid voltage fluctuation can be reflected to the rotation speed after a series of electromechanical inertia. When the speed feedback is adjusted, it is too late. After the current loop is increased, the voltage disturbance is Packaged in the current loop, it can be adjusted in time by current feedback, so that the dynamic deceleration caused by the grid voltage change is much smaller than the single loop system. As for the disturbance caused by the load, it is regulated by the speed loop because it is outside the current loop. Figure 2 Schematic diagram of double closed loop speed control

On the surface, the current negative feedback has a tendency to soften the characteristics. However, since the current loop is inside the speed loop, the current negative feedback is only a single disturbance. In the design, the magnification of the speed regulator can be made large enough. And, in the case of normal speed regulation, it is not saturated, then the disturbance of current negative feedback is suppressed. The deceleration that can be generated by the negative current feedback is completely eliminated by the integral action of the speed regulator. During start-up, the sudden feedback of the speed is not reflected, the speed regulator is in saturation, which is equivalent to the speed loop in the open loop state, and the system works under the regulation of the current loop. In this process, the system performance It is a constant current regulation system. Appropriate selection of parameters to achieve the basic idea of ​​"time optimal control".

The coal mining electrical control system adopts Siemens S7-200PLC programmable controller as the central processing machine. This model has high reliability, rich instructions, easy to master, and has rich built-in integration functions and strong communication capabilities. Ideal for shearer control. The internal PID regulator can meet the requirements of speed and current loop, and the peripherals are equipped with the necessary sensors and actuators to realize the operation control and dynamic brake control of the shearer. The control core adopts Siemens S7-200PLC, and expands two 4-input and 1-output analog modules EM235, and selects the ID-200 Hanxian module matched with S7200 as the display module. Peripheral accessories include: current transmitter, output relay and phase shift trigger circuit, thyristor rectifier circuit. In the control mode, the logic operation and the control part of the running speed are adopted. In the logic operation, the forward and reverse traction, the stop control, the rocker lift control, the brake gate switching control and the flow protection control are adopted. These functions are implemented by the PLC according to the interlocking relationship between the operation command and the feedback signal and various actions. By measuring the performance parameters during the actual operation, the rate of change of the rated speed during operation can be increased to less than 0.5%, and the accuracy of the steady operation can be increased to less than 1%.

3 Electromagnetic speed control electric traction shearer brake operation

When the dip angle of the working face is small, the control system will adjust the excitation current through the speed feedback, reduce it, and maintain the shearer speed unchanged. This is an advantage of the electromagnetic speed regulation mode. When the dip angle of the working surface is not too large, the system will Automatically reduces traction and maximizes the change in angle of the work surface. This feature eliminates the need for braking. We use different shearers for working faces with a dip angle of 20° to 30°, and the shearer can still operate normally. In the observation of the excitation current, it can be found that as the angle of the working surface increases, the excitation current in the downward operation gradually decreases.

When the dip angle of the working face is relatively large, the working resistance of the shearer is reduced, the excitation current is already small enough or even close to zero; and the speed of the load is still getting larger or larger. At this time, in order to ensure the normal operation of the load, it is required A braking force is generated, opposite to the negative force, to counteract the effect of this negative force. Figure 3 Schematic diagram of the brake

In order to adapt to various aspects, we have designed two manual and automatic braking functions. When the shearer is parked in the downward running process, when starting, it is necessary to start the manual mode directly. After the shearer starts, it is sliding. Under the action of the force, the shearer starts to run downwards. At this time, the excitation current is given as needed to make the shearer run at a certain speed. If the shearing force is gradually increased during the operation of the shearer, the electromagnetic speed control system can not effectively control the running speed of the shearer by adjusting the excitation current and reducing the electromagnetic torque, and the shearer enters the automatic braking program. . During the operation of the automatic braking program, the current and speed changes are always detected. If the current is decreasing, the speed still rises. The automatic braking system will enter the preparatory execution stage, first power off the prime mover and continue to detect the speed. The change, if the speed remains the same or has an upward trend, the system enters the braking process.

During the braking operation, the speed and current double closed loop control system is still used. From the field use situation, the electromagnetic speed control electric traction shearer can adjust the electromagnetic torque in a large range under the double closed-loop control of the computer when the load torque and the dip angle of the working face change, and the maintenance speed is basically unchanged. The coal machine is operating normally. In addition to adding a brake to the prime mover, the shearer itself does not add any components, has a simple structure, flexible control, convenient operation and normal speed regulation, and is very suitable for use under complicated conditions of coal mines. 4 Application of electromagnetic speed control shearer

In recent years, we have developed a variety of types of coal mining machines using electromagnetic speed control technology, covering almost all coal seams from thin coal seams to medium-thick coal seams. The MGN132/316-DW electric haulage shearer is a thin coal seam shearer with a height range of 1.1 to 1.9 m and a machine height of 853 mm. Due to the electromagnetic speed control electric traction method, the fuselage is thinner, the coal height can reach 326mm, and when the lm roller is used, the undercover amount is 160mm. The shearer of this type adopts the horizontal block type arrangement and multi-point drive. It has the characteristics of compact structure, large installed power and convenient maintenance. In the design, the motor and the slip coaxial arrangement are adopted, and the size of the electric control box is small, so that the length of the fuselage is reduced. The coal-passing space at the bottom of the shearer of this model is much larger than the height of the fuselage of the same type of machine. It is very unlikely that the shearer will “carry” the fault during the work. The shearer also adopts three kinds of control modes: manual, commander and remote control. The operation mode is very flexible, which provides convenience for on-site use.

The MXG-150/350D electric traction shearer has a height of 1100mm and is a new type of electric traction shearer with bottomless joists and lateral arrangement. It adopts the electromagnetic speed regulation electric traction as the traction power, the traction force is increased, the structure is simpler, and the body is short. In order to improve the stability of the whole machine, the span of the shoe is specially increased. The main parts of the fuselage are fastened together with hydraulic nuts and high-strength bolts. There is no bottom bracket, and the coal space and the amount of undercover are both The increase has been made and the overall adaptability has been strengthened. MX MXC-500/4.5D electric traction shearer with a height of 1685mm is a large mining shearer. The model adopts electromagnetic speed regulation and traction, and the traction force is 530kN. Although the traction is large, its control system is the same as the above two types of shearers, and the control current is still up to 5A, which is one of the advantages of this type of traction.

In the application, three kinds of electromagnetic speed-regulating electric traction shearers have proved their remarkable characteristics and superiority after production verification. MXG-150/350D is used in more than ten working faces of Dongpang Mine, Gequan Mine and Xiandewang Mine. The maximum inclination angle is 30° (the partial inclination angle of the 1424 working face of Gequan Mine), the MXP-350WD shearer is used, the weight is 25t, the working surface is the downswing, and the load torque is large. We use the advantages of electromagnetic speed regulation, reduce the excitation current, control the electromagnetic torque, and maintain the shearer running speed; Xiandewang Mine uses MGNl32/316-DW type electric traction shearer, the thickness of coal seam is 1.3~1.5m, The annual output of raw coal is 450,000 tons (including two moving); the inclination angle of 7809 working face of Xingtai Mine reaches 35°, using the MXP-500WD shearer, the weight is 48t, the direction is no angle, the load torque is small, no When the brake program is used, there is a slip phenomenon. After the brake program is used, the prime mover is braked, and then the excitation current is input to the electromagnetic speed regulating motor to form a braking torque, and the coal mining machine speed regulation operation is normal.

5 characteristics of electromagnetic speed control electric traction shearer

(1) Good control performance and large starting torque. After using computer control and double closed loop adjustment, the speed control performance of the shearer is greatly improved, the control performance is good, and the digital measurement, control and feeding make the shearer's stability better. Since the electromagnetic speed regulating motor is regulated under the normal operating condition of the prime mover, the starting torque is large and adjustable.

(2) The control power is small and the torque is large. In the control system of the electromagnetic speed regulating motor, the excitation current is controlled, the power current is not controlled, and the maximum is only 5A, which greatly simplifies the control system. At the same time, because of the control of the excitation current, for various electromagnetic speed regulating motors The same controller can be used, different parameters can be set for different electromagnetic speed regulating motors, and the control systems are all the same, which brings convenience to manufacturing and debugging work, and is more advantageous for mass production. Especially with the use of computer control systems, the advantages are more prominent.  Due to the small size of the electromagnetic speed regulating motor, high-power electromagnetic speed-regulating motor can be arranged in the same space. At the same time, with the further study of the electromagnetic structure, the output torque can be increased, which further enhances the electromagnetic speed-regulating motor. The load capacity has broadened the scope of use. 

(3) The voltage adaptability is good and the volume is small. In practical applications, the motor and the electromagnetic governor are installed together and occupy a small space. Moreover, since the control part is simple, the electric control box can be made small, and since the voltage of the prime mover of the electromagnetic governor can be the same as the voltage of other motors of the load, the shearer can be adapted to various voltages, and electric traction The speed regulation part does not require a high-power transformer, which can greatly reduce the size of the coal mining machine. This advantage is particularly valuable in the design of thin coal seam shearers. Because the thin coal seam shearer has a small coal-passing space, if the fuselage design is too long, the adaptability to the undulating working surface conditions will be affected, and even the phenomenon of “holding” may occur. 

(4) Brake running performance is good. When the load torque and the dip angle of the working face change, the electromagnetic speed control electric traction shearer can adjust the electromagnetic torque in a large range under the double closed-loop control of the computer, the maintenance speed is basically unchanged, and the shearer operates normally. When the shearer is running on the large dip working face, the computer analyzes the excitation current and the running speed to determine whether to enter the braking program. Braking procedures are divided into manual and automatic. The shearer itself does not add any components except for adding a brake to the prime mover. The structure is simple, the control is flexible, the operation is convenient, and the speed adjustment is normal. 

In summary, the electromagnetic speed control electric traction shearer has an innovative point in the speed control mode, and in order to make the electromagnetic speed control system better applied to the electromechanical traction of coal mining, the electromagnetic speed regulating motor and the controller are performed. Innovative research and successful application to the shearer makes the electromagnetic speed control electric traction shearer have large traction, good controllability, small control power, convenient voltage upgrade, and the volume occupied by the shearer and the electronic control part. Small features, and its simple structure, low cost, easy to use and maintain. Moreover, some of the disadvantages of the governor itself can be solved through technical means. All technologies have independent intellectual property rights. So far, the electromagnetic speed control electric traction shearer has several models of thin coal seam and medium thick coal seam. It has been used well in several coal enterprises and has withstood the test of complex working faces.

E-Stop Two Roll Mill

LINA Emergency Stop Two Roll Milling Machine

Two Roll Open Mill is a machine with a higher working accident rate, LINA E-Stop Open Two Roll Mill focuses on the machine`s entire safety system. For LINA Lab Series Two Roll Mill Machine, there are five safety devices installed:

(1). National patented 360° touching emergency button.

(2). Infrared safety sensor.

(3). Knee-touch emergency button.

(4). Roller protective cover.

(5). Emergency button on 360° rotatable panel.

(6). Reverse braking device.

Safety function is LINA Open Mill`s first consideration. It is worth to mention LINA Two Roll Open Mill`s safety devices have gained several national patents. LINA engineers have researched and developed comprehensive safety devices like 360 degrees emergency stop button, reverse braking devices, ergonomics safety device and infrared sensor etc.

Main Features:

Excellent appearance: LINA new design laboratory roll milling machinewith comprehensive optional functions and securedevices, which ensure the accuracy of formulaand high efficiency.

Safe guaranty: The roller adopts 360 degrees emergency and reverse braking devices, infrared automatic detection and ergonomics security to ensure operator`s safety.

Intelligent operation: LINA lab two roll open mill for product test PLC intelligent soft control system is easy to import or export data and record. Extremely accuracy in control and measurement of mixing temperature and ratio.

PLC intelligent control system: 1. Real-time data record and export of kneading time, temperature (mixing chamber and front/rear rotors), ram pressure, current, torque and recipe code. 2. The control system can be set up to 20 mixing steps, save 20 recipe spaces. 3. The control system is capable of remote importing of the process recipe and data monitoring, and communicating with MES via Ethernet communication interface. 4. An Ethernet communication interface and 20% of the control points are reserved. Touch screen is provided.

LINA Advantages:

· Quality guaranteed

Components are imported from Taiwan; the brand of reducer is LINA.

· PLC intelligent control soft system

This system can easy to import or export data, programming and recording, touch screen is provided.

· Single-shaft Transmission

Easy installation and operation, strong twisting force and low noise

· Anti-wear

The rollers are made of vanadium-titanium alloy, which is treated by nitriding and the surface hard chromium plating.

· High accuracy

Digital display and safe and easy adjustment

· Minimize damage from emergency

Multiple emergency braking devices

· Enclosed cooling system

Minimum pollution, excellent cooling performance

· Automatic lubrication system

Maintain continuous lubrication to extend its service life

· Mirror surface treatment of rollers

Clean up the material without dead corners, smoothly and evenly handle and easy discharge materials.

Specifications of LINA Open Mill Machine

Item	Technical Datum
Model		XK-120	XK-160	XK-200	XK-300	XK-360	XK-400	XK-450	XK-550	XK-560
Roller diameter	mm	120*350	160*350	228*600	300*700	360*900	400*1000	450*1200	550*1500	560*1530
Front roller liner velocity	r/min	19	18	16	13	11	11	10	9	8
Roller velocity ratio		1.24	1.29	1.27	1.3	1.2-1.3	1.2-1.3	1.2-1.3	1.2-1.35	1.3
Max pitch	mm	0-5	0-5	0-8	0-10	10	10	12	16	15
Machine output	kg	0.5-1.5	1.5-3	6-10	10-15	15-25	20-35	30-50	50-70	50-70
Voltage	V	380	380	380	380	380	380	380	380	380
Motor power	kw	5.5	5.5/7.5	7.5/11	15/18.5	30	45	55	90/110	160
Weight	KG	800	1000	1200	2500	6500	8000	10000	22000	22500

Rubber Two Roll Mill,Safe Rubber Milling Process,Emergency Stop Two Roll Mill,Emergency Stop Open Mill Machine

LINA Machinery Industrial Co.,Ltd , https://www.linakneader.com