The mine hoist is an important equipment in the production process of non-ferrous metal mines. The safe and reliable operation of the hoist is directly related to the production status and economic benefits of the enterprise. The coal that has been extracted is pulled by the hoist to the ground through the inclined shaft. There is a winch hoist at the wellhead. The motor rotates the drum through a reducer. The wire rope is wound on the service for several weeks. The two ends are respectively hung with a train of coal carriages. Under the drive of the motor, a train full of beakers is driven from the slope. The wells are dragged in. When the two empty vehicles are put down from the inclined shaft, the empty cars serve to balance the load. At any time, there will always be a row of heavy vehicles going up, no empty trip will occur, and the motor will always be in an electric state. This kind of drive system requires frequent forward and reverse movement of the motor, deceleration and braking, and the speed of the motor must change regularly. The power of the hoist is provided by a wire-wound motor, which uses a rotor resistor to adjust the speed. At present, most of the small and medium mines use inclined shaft winches to lift. Conventional inclined shaft hoists generally use AC winding resistance motor series resistance speed control system, resistance switching contactor relay AC contactor control. Due to the frequent operation of the AC contactor during the speed regulation process and the long operation time of the equipment, this type of control system is prone to oxidation of the main contacts of the AC contactor and causes equipment failure. In addition, the resistors on the external circuit of the garden generate considerable power consumption. This kind of AC winding type electric motor string electric yin speed regulating system belongs to graded speed regulation, and the smoothness of speed regulation is poor; at low speed, the mechanical characteristics are relatively soft and the noise is large; the power consumption of the slip on the resistance is large and the electric energy is wasted; In the course of process and speed shifting, current surge is large; medium and high-speed operation has great vibration and poor safety.
Retrofit Program To overcome the shortcomings of the traditional AC winding motor series resistance speed regulation system, a frequency conversion speed regulation technology is used to issue the hoist and constant torque control can be realized over the entire frequency range (0~50HZ). For the treatment of regenerative energy, an energy-saving braking scheme or a more significant regenerative braking scheme can be used. For safety reasons, the hydraulic mechanical brake and the original control system need to be reserved for backup, and the hydraulic mechanical brake and the frequency converter brake are integrated in the design process.
When driving with a frequency converter, short the three lead wires of the motor rotor. The load characteristic of the hoist is a constant torque bit energy load, and the starting torque is large. When the
Inverter is selected, the margin is properly left. Therefore, the power of the inverter must be greater than one-third of the full-load power of the motor. Because the hoist motor is in electric state most of the time, the public will generate regenerative energy in a few moments. The inverter will be connected to a brake unit and braking resistor to meet the regenerative braking when the heavy truck descends, achieving a smooth Down. The wellhead also has a hydraulic mechanical brake, similar to the electromagnetic brake. This brake is used to brake the mini-vehicle at rest, especially when the heavy vehicle is parked on the slope of the well or when it is imported, it must be braked by a hydraulic mechanical brake. Whether the brake is controlled by the inverter frequency reaching the port. When the inverter output frequency reaches the set value during start-up, for example, 0.2HZ, the inverter output signals at terminals 30B and 30C indicate that the motor torque is large enough to open the hydraulic pressure. Mechanical brake, the mini-vehicle can be up; when the frequency of the inverter drops to 0.2HZ during deceleration, it means that the motor torque is smaller, and the hydraulic machinery brake stops and stops. In case of an emergency, pressing the emergency stop button, the inverter energy braking and the hydraulic mechanical brake are applied at the same time, so that the elevator stops in the shortest possible time.
The conventional operating mode of the hoist is that the operator sits in front of the coal mine wellhead and controls the motor with the joystick and reverses the speed of each of the three gears. In order to adapt to this operation method of the operating worker, the frequency converter adopts the original control method to achieve stepless speed change, so as to prevent the change of the control mode from bringing unnecessary trouble to the operator.
The hoist is the same regardless of forward rotation or reverse rotation. It has seven stages: starting, accelerating, medium-speed running, stable running, decelerating, low-speed running, and braking. The time for each lifting operation is related to the operating speed of the system and the depth of the inclined shaft. The acceleration of each section is determined according to the process conditions, and the operating time is determined by the operating personnel according to the conditions of the site.
Our company produces frequency conversion hoisting electrical control system for low voltage 380V-660V variable frequency electrical control equipment, applicable to the ground hoist or 50KW-800KW mine hoist in non-explosion-proof occasions, with various types of hoisting machine driven by low voltage motor, Especially for the multi-rope, multi-level, double machine, inclined wells and other complex operational occasions, with advanced technology, economical and practical, safe and reliable, low failure rate, easy maintenance and so on.
1. The speed control system adopts the micro-energy all-digital WIN-VC series variable frequency speed control device to form a variable frequency speed control system with four-quadrant work performance, and achieve high dynamic performance of frequency control, speed control, torque control;
2. The main control system adopts two original Japanese Mitsubishi FX-2N series programmable controllers, advanced technology and reliable programmable logic controllers (double PLCs) to achieve intelligent control through a two-wire safety loop system;
3, comfortable color touch screen animation operation panel, display winch system to enhance the signal, running speed, lifting stroke and other parameters, can achieve the inverter settings, start, stop, the LCD screen can easily monitor the inverter's running status, The function of fault alarm status setting process.
4. The lifting
Electric Control System consists of three main control devices, with an additional shaft encoder and necessary external control terminals.
January 29, 2021