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1. The shortcomings of traditional mine hoists
Conventional mine hoists generally use a series circuit of rotor loop resistors, which use the disconnection and closing of the contactor to achieve step-by-step speed regulation of the motor. This control method has the following obvious disadvantages:
◆ The series resistance speed regulation belongs to the pole speed regulation, the starting impact is large, and there is a speed jump in the speed switching, which is easy to drop, and the danger is high, which seriously affects the production efficiency and the safety of people's lives and property, especially when the transporter when.
◆ Using string resistance to regulate the serious waste of electrical energy on the resistance, the lower the speed, the more serious the waste; when the object is lowered, the motor is in the power generation state, which wastes energy even more seriously.
◆ Rotor string resistance speed control, high failure rate, large maintenance workload, due to the use of contactor string resistance speed regulation, frequent switching in the process of speed regulation causes the contactor to be damaged frequently, resulting in malfunction of the speed regulation, there is a safety hazard, and Increased maintenance workload.
◆ Poor stability and speed change with load.
◆ The starting torque is not enough, especially when it stops in the slope and can't be restarted. It is necessary to put the material down to a stable place and start again, which seriously affects the production efficiency.
2. V&T Inverter Mine Hoist Control Integrated Solution has obvious advantages in driving the motor
◆ Adopt advanced DSP chip and excellent vector control to match the power required by the hoist and the output power of the inverter;
◆ The starting current is small, the starting speed is stable and no impact, which greatly reduces the down-going phenomenon;
◆ High reliability, the inverter has perfect protection functions, such as overcurrent and overvoltage overload and short circuit protection functions;
◆ Low maintenance workload. There is no need to replace the contactor frequently as in the conventional solution, which greatly reduces maintenance costs;
◆ Wide range of speed regulation. It belongs to the stepless speed regulation, the motor control is stable during the acceleration and deceleration process, and the hand feel is soft when the speed is adjusted.
The reliability of the system is high, and there is no heat generated by the string resistor, which greatly improves the working environment of the operator.
◆ Large energy saving space. When the mine hoist is in the elevated state, the energy saved is proportional to the speed; when in the lower state, the motor is in the power generation state. If the energy feedback unit is used, the energy saved is not only proportional to the rotational speed, but also the energy fed back. ;
◆ Moreover, it has the automatic switching function of transporting people and things. When transporting people, it can automatically limit the maximum speed, making the transporter more safe and comfortable.
◆ It can be used perfectly with mechanical brakes and safety circuits. When using mechanical brakes, the inverter will not experience overload and over-current, and it can automatically realize mechanical brakes in case of emergency or power failure, maximizing the protection. Safety;
◆ Greatly improved production efficiency, high stability, and speed does not change with load changes;
◆ It can eliminate the hook phenomenon. Even if the mechanical brake is carried out in the middle of the ascending process, it is not necessary to put the heavy object on the flat ground to restart, and the heavy object can be pulled up without slipping in the middle;
◆ The rising and falling processes are interlocked, and it is not easy to cause operational errors;
◆ When running at high speed, it is not possible to change the running direction at will, to prevent the inverter from automatically stopping or reversing due to accidental signaling during operation.
◆ Do not change the original operating habits;
◆ Support power frequency and frequency conversion switching function;
◆ The operation panel has a parameter copy function, which greatly reduces the workload of debugging and maintenance.
3. About the brake brake of the winch◆ About the brake problem of the winch:
1.1. The “+” and “—” terminals of the brake unit are connected to the “+” and “—” terminals of the inverter.
1. 2. Braking resistor terminal of braking unit is connected to braking resistor
Note: The load on the winch is heavy, and the selection of the brake unit and braking resistor should be large enough. Regarding the feedback device, the installation method refers to the instruction of the feedback unit. It is recommended to use the brake unit for a high cost performance.
◆ Brake problem of safety circuit:
The mine is a very safety-conscious place. It must be equipped with mechanical brakes. It must be ensured that the mechanical brake can completely brake the car under any abnormal conditions. For example, in case of emergency, when the inverter fails, suddenly power failure occurs. At the time, etc., it must be ensured that the mechanical brake can fully perform the brake; When the inverter is in the stop state or the inverter has almost no speed, if it does not have the brake function, it needs mechanical braking;
The inverter has various protection functions, such as over-current over-voltage overload and under-voltage protection. When a fault occurs, the inverter stops outputting the motor immediately, so the brake protection is required at this time.
As can be seen from the above, the entire system must have the above security protection functions. Normal winches should have the above functions integrated into the safety loop of the winch. When there is a problem in the safety circuit, immediately start the mechanical brake and immediately output the switch signal to prohibit the inverter from running. This switch is connected to the X terminal of the inverter. The function setting is 22: The inverter operation is prohibited.
◆ Problems with manual mechanical brakes:
In the normal driving process, the brake and winch brakes are fitted with a contactor in the middle of the mechanical brake. When the brake is actuated, a signal is output to the inverter. This function is set to 21: External interrupt contact Input, (if set to X4), it is best to output a signal to the drive when the brake is released halfway (half tight).
If the current state is the stop state, then the brake of the winch is holding tightly. At this time, the inverter is started. At this time, the brake is slowly released. When the release is not halfway, the X4 terminal should be closed. Although the inverter runs, it is in the blocked output state, and the output frequency is zero. When it is released to half, the X4 terminal is set to the off state. At this time, the potentiometer is turned to a little speed, and the inverter starts running. When you hear the sound of the motor, it means that the torque of the inverter has been fully established, and then slowly release it. At this time, the potentiometer is rotated and the motor speed can rise slowly.
When the winch is in operation, prepare to brake the winch with mechanical brakes. At this time, you can slowly slow down slowly. When it reaches a certain level, slowly tighten the mechanical brake. When the mechanical brake is halfway, the above setting is made. The function terminal No. 21 is closed. At this time, the inverter blocks the output, and the mechanical brake brakes the winch to stop.
4. Pay attention to◆ At present, the inverter is suitable for environment without gas and coal dust explosion, environment without significant vibration and impact, ambient humidity: ≤90%, waterless condensation, power supply voltage: AC380V50Hz, if explosion protection is required, please choose Blue Ocean Huateng explosion-proof Series inverters.
◆ In mine production, it is necessary to ensure the availability of safe protection devices, such as checking whether the brake system is intact, whether the gap of the gate is normal, and whether the direction is interlocked;
◆ The electromagnetic mechanical safety brake is electrically interlocked with the inverter. After the electromagnet is energized, the inverter can be started. After the inverter fails, the safety brake is tight.
◆ The inverter forward/reverse switch is electrically interlocked with the manual brake. The inverter cannot receive the start signal until the manual brake is released.
◆ The electric lock of the manual brake is electrically interlocked with the speed-regulating potentiometer. When the potentiometer is adjusted to 0V for 5Hz operation, the manual brake is returned once, the inverter immediately outputs at zero speed, and the inverter is stopped at the same time.
◆ From the perspective of safety, the inverter power should be greater than the rated power of the motor. For example, if the motor is 220KW, the selected inverter should be at least 280KW. In addition, a dynamic braking unit or a feedback braking unit is required. The coal mine is a very safe place, requiring mechanical brakes and safety circuits. Fully coordinated.
V. Renovation Case 1: Reconstruction of large winch in a city's leading coal mine (180kW)
◆ Wiring diagram of the main circuit and control circuit of the inverter (the wiring diagram of AI2 is not shown here):
◆ Power frequency frequency conversion system switching schematic diagram and switching method:
When using the inverter, please connect the power switch to the inverter input power R, S, T, and connect the motor wires U, V, W to the inverter motor output terminals U, V, W, and also need to shorten the rotor circuit of the motor. Connect
When using the power frequency, the switching power supply is connected to the original operating system. In addition, the motor wires U, V, and W need to be connected to the power frequency power supply. In addition, the rotor wire needs to be connected to the original string resistance circuit.
◆ Debugging methods and steps:
1. Input parameters according to the motor nameplate:
P0.11: Maximum frequency, set according to site requirements;
P0.13: The upper frequency limit is set according to the site requirements. This value can be the same as the P0.11 setting.
P0.12: Maximum output voltage, please set according to the motor nameplate;
P0.15: Basic running frequency, please set according to the motor nameplate;
P9.00: Load type, please set 0, which means overload;
P9.01: Number of motor poles, please set according to motor nameplate;
P9.02: rated motor speed, please set according to the motor nameplate;
P9.03: Motor rated power, please set according to the motor nameplate;
P9.04: Motor rated current, please set according to the motor nameplate;
2. Set P9.15=1 to perform motor static self-tuning, and it will automatically stop after self-tuning.
3. Connect the potentiometer to between 10V, AI1 and GND, then set
P0.04=1: given frequency through AI1
P0.06=1: terminal control
P3.09=0, allow reverse
P6.00=4410, AI1 and AI2 are corrected by curve. When transporting people, switch potentiometer to limit speed.
4. Set the function of multi-function input terminal:
P5.00=2: X1=forward rotation
P5.02=20: X3=Fault reset
P5.03=21: X4= external interrupt contact input, connected to mechanical brake signal
P5.04=22, X5=Disabled inverter operation, connected to safety loop
P5.05=55, X6=human-car signal switching, connect a potentiometer at the AI2 end, and switch the frequency source when the transport needs to speed up;
P5.06=26, X7=fastest parking;
5. Set the multi-function output terminal:
P7.00=00: Y1=Inverter running signal
P7.01=15:Y2=inverter alarm signal
P7.02=14: Relay = inverter fault signal
6, connected to the analog output terminal:
P7.03=53: AO1=inverter output voltage
P7.04=50: AO2=inverter output current
5. Transformation case 2: transformation of a medium-sized winch in a coal mine in a city (95kW, 55kW)
◆ The main circuit and control circuit wiring diagram of the inverter:
◆ Parameter setting:
1, motor parameter settings:
P9.01=****, the number of motor poles, please set according to the motor nameplate
P9.02=****, motor speed, please set according to motor nameplate
P9.03=***, motor power, please set according to motor nameplate
P9.04=***, motor rated current, please set according to motor nameplate
P9.15=1, press RUN key after pressing to perform parameter auto-tuning
2, function parameter settings:
P0.04=1, analog given frequency
P0.06=1, terminal control run command
P0.08=50, acceleration time (set according to actual situation)
P0.09=15, deceleration time (set according to actual conditions)
P2.00=3, keyboard lock function
P3.03=2, starting frequency
P3.04=0.5, starting frequency retention time
P3.09=0, allow reverse
P5.00=2, the terminal runs forward
P5.01=3, terminal reverse running
P5.02=20, fault reset input
P5.03=24, the terminal is free to stop
P5.04=22, the inverter is forbidden to run
P5.05=26, fast shutdown
P5.06=52, the main frequency source is cut to the number
P6.00=4440, analog correction
P6.02=5Hz, analog 0V corresponds to 5Hz
P7.00=14, output frequency conversion fault
P7.02=0, the signal is running in the inverter
P9.18=20, motor overload protection time
PA.09=1, energy brake has started
◆ On-site situation before the renovation:
The coal mine has two one-way 28 degree slope hoist winches. The components are: motor power 90KW one and 55KW each, roller, gearbox, manual mechanical brake, electromagnetic mechanical safety brake, over-roll protection limit switch Positive/reverse five-speed resistance speed control box.
◆ On-site situation after renovation: The original components are: motor power 90KW one and 55KW each one, roller, reducer, manual mechanical brake, electromagnetic mechanical safety brake, over-roll protection limit switch, positive/reverse five-speed resistance speed control box. Do not interfere with the original operating system, then add accessories: inverter, brake unit, braking resistor, reactor, potentiometer, intermediate relay, button, indicator light, three-speed switch, travel limit switch.
1, potentiometer: winch speed adjustment.
2. Intermediate relay: The output power of the output lamp in the middle/stop of the winch, the inverter output indication, and the safety brake after the inverter fails.
3. Button: Inverter fault reset / fast stop.
4. Indicator light: Inverter fault indication.
5. Three-speed switch: The inverter rotates forward/stop/reverse.
6. Stroke limit switch: When the manual brake returns to the position, the inverter terminal is freely stopped, and vice versa.
◆ Problems in the debugging of winch inverter:
On the morning of commissioning, at the main wellhead, install the 90KW winch inverter function control line. The control line is exactly the same as the auxiliary well winch. The principle is: “After the inverter is started, the potentiometer can be adjusted to 0Hz operation, with manual brake, no The inverter is overloaded, and the winch's body does not fall when the half-slope starts/stops." In the afternoon, the man and the car were put down and the well was drilled. The passenger car weighed about two tons, and the inverter did not have any problems. Then, returning to the auxiliary wellhead to test the heavy load of 55KW, when the vehicle is tested back and forth in the underground, the weight of the bucket is about three tons. At this time, the vehicle is falling and the inverter overload fault occurs. Analysis, summary, the problem is in the action coherence of the manual brake and the tightness of the car skin. I thought a lot of plans, and finally decided to add a set of normally closed switches as the operating instructions of the inverter in the killing action, and adjust the car to the moderate position.
When a set of normally closed switches is added to the manual brake return position of the 55KW winch at the auxiliary wellhead, when the manual brake returns to the position, the normally open of the top-to-stop switch becomes normally closed, normally closed and normally open, the inverter The terminal is free to stop. When the car is pushed open, the normally closed of the travel switch is restored to the inverter running command, and the inverter is started from 2 Hz, thus solving the downward phenomenon of the inverter overload fault and the winch when the semi-slope is stopped. Later, the winch control line of the main wellhead was changed to the same, with heavy-duty debugging, no problems, the winch boot operation became very convenient.
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