First, the hoist features:
Coal mine hoist winch drive system adopts winding type AC asynchronous motor, and the rotor loop is internally cascaded with multiple stages of external resistance speed control. Cam controller, relay and contactor control are used. The main disadvantages of this control system are:
1. Motor rotor series resistance is an energy-saving type of slip speed control, high energy consumption, soft mechanical characteristics, small speed range, and poor smoothness.
2. Relay-contactor controller system In the case of frequent switching, the inrush current is large, the contacts are burned, the brush is ignited, and the resistance of the motor and rotor is burned and broken.
3, poor smooth speed regulation, mechanical impact on the reducer, coupling, wire rope.
4. The brake system of the system is carried out under running conditions. It has great damage to the brake and the brake shoe wears badly.
5. The speed regulation is not continuous during hoist operation and it is easy to fall off.
Second, the frequency of non-influence vector control cabinet 1, the transformation of the schematic: In order to ensure safety and reliability, let the frequency control system and the original speed control system coexist, mutual backup, ready to switch. At the same time, in order to allow the operator not to change the operating habits, the engineering and frequency conversion systems are operated by the original operating mechanism, leaving the original operating system and operating mode unchanged.
2. Replace the original series resistance with AC frequency converter, through the multi-speed function of the inverter, and the relay and contactor control system to realize the stepless speed control of the hoist. The coal mine hoist system belongs to the potential energy load. In order to ensure the reliable operation of the system, a braking unit and braking resistor must be added.
Third, the system's advantages:
1) Soft start soft stop. Reduced mechanical shock, very little impact on the grid when starting and accelerating shifts, making the lifting system and grid operation more stable and reliable. The functions provided by the inverter itself combine the mechanical braking with the electric braking to ensure the system The absolute safety.
2) Peripheral control uses PLC. With its various sensors, it forms a closed-loop control (open-loop control can also be used). The friendly human-machine interface monitors the operation of the system from time to time, simplifies the system configuration, and reduces the labor intensity.
3) Stepless speed regulation is achieved. The speed range is wide, and the running curve is S-shaped, making the acceleration/deceleration smooth and without impact.
4) The safety protection function is complete. IP54 enclosure protection, in addition to the general inverter over-current, DC over-voltage, DC under voltage, inverter over temperature, short circuit, input phase loss, ambient temperature, over-frequency, I / O control board internal fault, but also programmable Fault protection function, AI
5) System 4 quadrant operation. The energy is directly fed back to the grid, and is not limited by the size of the feedback energy. This ensures that the elevator can be frequently stopped, started and reversed during operation, thus saving a lot of electric energy.
6) High control accuracy and good dynamic performance. All-digital, IGBT inverter inverter units provide variable-frequency power to the load, allowing all control functions to be set by parameters. Direct torque control enables high dynamic performance speed control and torque control. The use of a rotary pulse encoder enables accurate positioning of the lifter. Saving rate can reach more than 30%!