Mine hoisting systems are oriented on carrying out the essential transport function of a mining – on the movement of personnel, the rock mass and equipment on shafts and slope. In accordance with this cage and skip installation are differentiated, as well as underground mine lifting machines and hoists, which make up a separate group of technological lifting machines – Installations of one-ending haulage [1].
Typical structure of the lifting machine (Fig. 1) implies having basic element - an automated electric drive with such structural elements as: engine 1, gear 2, clutch 3, braking device 4. The operating body of the drive is a drum 5 of the lifting machine with rope 6. Control in both automatic and manual modes is perfomed by remote control 7.
1 - Engine 2 - reducer;
3 - Clutch, 4 - drum hoist;
5 - rope, 6 - brake, 7 - panel of lift driver.
In contrast to major mining lifts (skip, cage), which are applied mainly DC motors, synchronous motors and induction motors with squirrel-cage systems, the drives of one-ending haulage use asynchronous motors with slip-ring motors, which are used to solve the main task - to ensure a smooth start-up or start on a given speed chart.
Block diagram of the object shown in Fig. 2.
Based on the technological conditions of work, in addition to general requirements for lifting equipment, automated system of one-ending haulage must provide the following additional requirements: maintenance of a given chart speed of ascent and descent when the load winches ranging from 20 to 130% of nominal; automatic execution of a given chart speed of ascent in case of control from any operation platform slope and a given speed of descent in case of the control from the closest to the winch receiving area; the possibility of manual control for running some operations, which are provided for by the principal tachogram. All this requires effective and efficient means of controlling the speed of drive motors. This problem is being decided on the basis of applying rheostat, or cascade control devices of speeds of the engine that has a low efficiency, the complexity of automating of the maintenance of a given chart speed at fluctuations of the load (rheostat control), or significant cost (cascade control). Therefore it is important to further improve devices for automation of control by the speed-mode of one-ending haulage.
The objective of the investigation is to increase the efficiency of induction motor of one-ending haulage on the basis of grounding options and application of thyristor regulator of the rotor current.
To achieve this goal should be solved the following problems:
- Analysis of the characteristics of devices and operating one-ending haulage;
- Analysis of existing methods and devices of control asynchronous motors;
- Justification of the rationality of thyristor regulator rotor current;
- Algorithmization and development of the block diagram of the control;
- Development of the concept of functional blocks of the control;
- Justification of operational requirements for the designed device.
A scientific ground of parameters of control system by the thyristor regulator of rotor current is in the electromechanic of one-ending haulage.
When writing this abstract the master’s qualification work is not completed. Date of final completion of work: December, 1, 2011. Full text of the work and materials on a work theme can be received from the autor or his scientific supervisor after that date.