Vol 45 Iss. 1

The Research Laboratory of Automation and Telemechanics in Mining (ATM) was organized in 1957 and was attached to the Department of Mining Electrical Engineering until 1960, after which it was transferred to the Department of Automation of Production Processes. Four main sections were established in the laboratory: automation of mine electric drive control; automation of mine electrical network devices; telemechanics, signaling and communication; high-frequency technology and electronic devices.

A power three-phase transformer with smooth voltage regulation under load has a common magnetic core M with division into nine limbs arranged in a plane. The three main limbs 2, 5 and 8 are used for winding the primary phase windings W₁. The six additional limbs 1, 3, 4, 6, 7 and 9 house the DC biasing windings Wd. Secondary phase windings W₂ are located on nine limbs: three on the main limbs 2, 5, 8 and two on additional limbs 1, 3, 4, 6, 7 and 9. The compensating winding W_k is wound on all additional limbs. Deep smooth regulation of the secondary voltage of the transformer is carried out by changing the value of the DC current in the six DC biasing windings Wd.

The domestic mining industry has begun introducing multi‑rope hoisting machines. Eight such units are being installed in the mines of the Stalin region. Design organizations are designing a number of multi‑rope hoisting installations of various capacities and various purposes. Due to the specific design and layout features of multi‑rope hoisting machines, the drive is subject to special requirements. The mandatory presence of a tail rope makes the hoisting system balanced. The small drum diameter significantly reduces the torque on the main shaft, facilitates gearbox design, and allows the use of relatively high‑speed drive motors. Calculations by design organizations show that for multi‑rope machines during normal hoisting in the deceleration phase, as a rule, the drive must operate in the motor mode.

Automation of the G-M drive of a mine hoist and excavators is closely related to the use of electromechanical amplifiers in it — special electrical machines with a high gain and high response speed. These qualities of electromechanical amplifiers have determined their widespread use and contributed to the development of various control schemes built on a closed loop. However, the operating experience and research of G-M drives of mine hoisting and excavators with electromechanical control show that systems with electromechanical amplifiers are very complex, the transients in them have an unfavorable character; in general, the operation of these drives is not reliable or stable.

Electromagnetic slip clutches (EMC) are widely used in various drives: mechanisms with fan load torque (electric drives of induced draft fans at power plants), ship propeller shafts. In ship propeller shaft drives, EMCs are particularly widespread and their power outputs reach several thousand horsepower. Recently, EMCs have been used for other types of electric drives : excavators, drilling machines, metal-cutting machines, etc.

The main drives of the EKG-8 excavator are made according to the G-M system and have a control scheme based on electromechanical and magnetic amplifiers (EMU-PMU cascade). This scheme, as tests have shown, has a number of drawbacks. At present, in connection with the transition to mass production of EKG-8 excavators, there is a need to develop simpler and better automatic control schemes. Promising in this respect are control schemes of electric drives of the excavator built on the basis of magnetic amplifiers (MA). When developing such schemes, it is very important to correctly build the excitation circuit of the generator, as it largely determines the structure and parameters of the control circuit as a whole and, ultimately, the properties of the drive.

In engineering calculations of dynamics of automatic control systems, the problem of determining the region of permissible parameter changes usually arises. For linear systems it is possible to obtain such a region by repeated machine solution of the system equation of motion or with the help of indirect methods (frequency, integral criteria, etc.). For nonlinear systems, this problem is often reduced to the construction of the region of permissible changes in the forms of nonlinear couplings, so indirect methods are either not applicable at all, or have an algorithm that is too complicated for practical application. The method of multiple partial solutions for nonlinear systems is obviously possible only in a few special cases. A number of similar problems are reduced to the task at hand: determining the influence of neglected couplings and the legitimacy of this or that approximation, estimating the accuracy of the approximate solution of the system's equation of motion, etc.

In electromodeling of nonlinear systems, there arises a problem of estimating the methodological error of the model connected with the approximate implementation of given functional dependencies and perturbing forces. This error, called the dynamic approximation error, is inevitable when using series-produced electromodeling devices and in magnitude can exceed other components of the error.

Magnetic amplifiers (MA) with self-saturation, owing to a number of advantages, are widely used in automation circuits. The development of sufficiently simple methods for calculating transients in such circuits is a pressing task. Since one of the most effective ways to study the dynamics of automatic control systems is analog simulation, when developing engineering calculation methods it is advisable to allow for the possibility of using series-produced analog simulators.

Issues of automatic voltage regulation in local electrical networks are an important part of the overall problem of complex mechanization and automation of production processes in the mining industry. A stable voltage level is necessary for the stable operation of automatic devices, more complete utilization of the natural mechanical properties of electric drives, and reduction of electric energy losses in local distribution networks.

At the present time, electric locomotive haulage is the most difficult to automate in the chain of all processes of mining technology, so in mine transportation one is still limited to only production signaling and communication. Sometimes, only the switching of turnouts and opening of doors when an electric locomotive passes are automated. The main obstacles to the automation of electric locomotive haulage are unsatisfactory characteristics of the rolling stock, the condition of haulage tracks, and the power supply system. Poor track superstructure and uneven profile of tracks in mine workings, where people pass simultaneously with the movement of electric locomotives, complicate locomotive control operations. Due to the harsh operating conditions, electric locomotives are equipped with series motors. The smoothness of the traction characteristics of the motors exacerbates the instability of the electric locomotive operating modes. The suspension of contact wires is often unsatisfactory, and large voltage fluctuations are observed in the supply lines.

The operational work of a modern coal mine depends to a large extent on a properly and quickly functioning production communication system. The existing mechanical and electrical systems at the mine — shaft signaling between the receiving platforms and the machine room — although reliable in operation, cannot fully satisfy all the requirements of the hoisting operation. Thus, for example, in any accident involving the jamming of a cage in the shaft, when it becomes necessary to signal directly from the cage, an imperfect and inconvenient traction signal has to be used. It is even less convenient to use such signaling during work in the shaft (inspection and repair of guides, shaft lining, cable laying, etc.) associated with frequent stops and movements of the hoisting vessel (cage or skip) for short distances.