Linear electric motors are applicable in mine electric locomotive rolling, their introduction on monorail roads is a significant step forward in the technical progress of transportation. This achieves high efficiency, high power per unit weight, simplicity of construction, which facilitates repair and maintenance in operation, provides traction on steep ascents, eliminates noise and vibration during operation, there is no contact between moving parts. ...
One of the urgent issues of operation of belt conveyor lines of the mining industry is the improvement of existing and finding new ways of cleaning conveyor belts ...
If the thrust force of the engines exceeds the tractive force due to the clutch, slippage of the wheels of the driving half-skates will occur along with the forward motion of the locomotive. The velocity at the electric locomotive wheel rim will be added up from the translational velocity of slippage. In this case, the energy consumption of the locomotive engines will increase sharply. Energy will be additionally spent on abrasion of wheel bandages and rolling rail heads ...
Mine electric locomotive pumping by contact DC electric locomotives with rheostat control has a number of significant disadvantages. The presence of a converter substation reduces the reliability of power supply of the electric locomotive rolling. Stray currents reach a significant value in the DC system of rail transportation. Underground metal structures (cables, pipelines, etc.) located in the zone of stray currents are subjected to electrolytic corrosion ...
In the current state of electric locomotive rolling is the most difficult to be automated in the chain of all processes of mining technology, so in mine transportation is still limited to only production signaling and communication. Sometimes, only switching of switches and opening of doors when an electric locomotive passes by are automated. The main obstacles to the automation of electric locomotive rolling are unsatisfactory characteristics of the rolling stock, the condition of rolling tracks and the power supply system. Poor top structure and uneven profile of tracks in excavations, where people pass simultaneously with electric locomotive movement, complicate electric locomotive control operations. Due to the harsh operating conditions, electric locomotives are equipped with serial engines. The softness of the traction characteristics of the engines aggravates the instability of the electric locomotive operating modes. The suspension of contact wires is often unsatisfactory, large voltage fluctuations are observed in the supply lines.
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. Stable voltage level is necessary for stable operation of automatic devices, more complete utilization of natural mechanical properties of electric drives, reduction/loss of electric energy in local distribution networks.
The operating mode of traction motors of mine electric locomotives is poorly studied. There is no theoretical justification for the selection of traction engine power to a given locomotive weight. In the USSR and abroad the ratio of engine power to locomotive weight is taken differently by different plants and firms. American companies, for example, for 1 t of locomotive weight take engines with power from 6.95 to 8.76 kWt, West-German - from 4.62 to 6.57 kWt, plants of coal machine building in the USSR - from 5.88 to 6.57 kWt. Thus, American electric locomotives have a higher specific power. Increasing the specific power of an electric locomotive guarantees traction motors from possible overloads. This is a positive factor. If the forces of resistance to the train movement exceed the traction force provided by the coupling weight of the locomotive, the driving wheels will start slipping and there will be no further increase in the power consumed by the engines. At the same time, the automatic limitation of traction motors loading will be provided by the value corresponding to the electric locomotive coupling weight.
При современном развитии горной электротехники в качестве тягового двигателя на рудничных электровозах применяется сериесный двигатель постоянного тока. Он наилучшим образом удовлетворяет требованиям рудничных электровозов при работе на шахтных откаточных путях. В настоящее время шахтные откаточные пути характеризуются весьма слабым верхним строением, резко переменной величиной уклонов, наличием кривых малого радиуса закруглений и в ряде случаев обводненностью и загрязненностью рельсов. Такое состояние откаточных путей, естественно, приводит к ухудшению работы подвижного состава, быстрому износу ходовых частей электровоза и вагонов — к увеличению сопротивлений движению всего состава. Условия работы тягового двигателя рудничных электровозов обычно имеют резко переменную величину нагрузки. Статические сопротивления движению часто принимают отрицательные значения. При наличии других дополнительных сопротивлений движению тяговый двигатель фактически работает все время на переходных режимах — в разгонах и замедлениях.
В настоящее время в условиях угольных шахт основным видом транспорта по главным горизонтальным выработкам является электровозная откатка. На газовых шахтах откатка производится электровозами аккумуляторными, а на шахтах, не опасных по газу и пыли, — контактными. Такой вид транспорта в современных условиях — при комплексной механизации угледобычи — обладает рядом существенных недостатков. Зачастую он является причиной нарушения непрерывности процесса транспортирования полезного ископаемого. Часто имеют место нарушения графиков движения. Для современных крупных шахт — при комплексной механизации угледобычи с полной автоматизацией — наиболее прогрессивным видом транспорта является конвейерный. Он легче поддается автоматизации, позволяет сохранять непрерывность процесса транспортирования полезного ископаемого от забоя до железнодорожных бункеров или обогатительных фабрик и является менее опасным для обслуживающего персонала.
A new method for selecting power supply elements is presented for discussion, which allows for increasing the accuracy of calculations for traction networks and substations for mine electric locomotive haulage. This calculation method allows for taking into account all the main factors that determine the conditions of electric locomotive traction: the productivity and length of haulage sections, track slopes, the size of the train, travel time, etc. Unlike existing methods, the time of movement of the electric locomotive under current during the trip is taken into account separately, which significantly affects the total load value. The calculation completely excludes the subjective method of selecting calculation parameters: cross-sections according to schedules, train placement on the line, the number of simultaneously operating electric locomotives, the number of electric locomotives in starting mode, etc. Load currents are taken as average integral values, related to the time of movement of the electric locomotive under current, and not to the total time of movement or trip. During calculations, it is possible to check not only the magnitude of the overload, but also the duration of its action and the repetition frequency. The new calculation of power supply elements is part of the general calculation methodology for electric locomotive traction. It is based on the initial data for determining the rolling stock elements (number of cars in the train, total number of electric locomotives) and on the calculation of the elements of the movement of the electric locomotive haulage (traction force, speed, current value and travel time). The technical calculation when choosing the most advantageous option includes elements of economic comparison.
In the existing calculation methods of mine electric locomotive haulage for determining the elements of motion - traction force, speed and time of movement, energy consumption - an average or equivalent slope of the haulage tracks is usually adopted. An equivalent slope is a constant slope that is equivalent to the actual profile in terms of the operation of traction motors. For newly designed coal and ore mines, a slope of equal resistance or close to it is often adopted in calculations of mine electric locomotive traction, ensuring normal drainage of water from the workings. A slope of equal resistance is understood to be a constant slope at which the traction force of the electric locomotive when moving with a load downhill and the traction force when moving with an empty train uphill will be the same. The calculations imply that the operation of electric locomotives at a steady speed of movement occurs without acceleration, with a traction force and, accordingly, with a current value corresponding to the uniform movement of the train on the adopted constant slope.
The usual methods of calculating mine electric locomotive haulage are very simple, convenient for operational calculations and for selecting elements during design. With some assumptions in the generally accepted traction calculations, they become quite elementary. The traction calculation is greatly simplified with the introduction of the so-called equal resistance slope, i.e. such a slope of the track at which the traction force during the movement of the electric locomotive in the freight and empty directions is the same. The calculation of the check of traction motors for heating becomes elementary, if we assume that the current strength is directly proportional to the traction force of the motor. Significant simplifications are also introduced into the calculations for determining the elements of power supply networks, converter substations and energy consumption. The simplicity of the calculations is an advantage of the existing methods of calculating underground electric locomotive haulage, especially since in most cases these assumptions and simplifications insignificantly affect the accuracy of the calculation. However, in a number of cases, the existing calculations are incomplete and do not provide a final answer. In particular, this is observed in traction calculations. The task of traction calculations includes determining the elements of the rolling stock of an electric locomotive haulage - the size of the train composition and the adhesion weight of the electric locomotive.
The observations of electric locomotive haulage at the mines of Kounrad, Magnitogorsk, Karaganda and Cheremkhovo revealed a significant discrepancy between productivity and design data. In a number of cases, the actual productivity of electric locomotive haulage did not reach even 50% of the estimated one. Timekeeping data for the Magnitogorsk open-pit mine, as well as for the mines of the Cheremkhovo coal basin, indicate unproductive waste of time on various delays and accidents due to inconsistency in the work of individual transport links, transport with sections and quarries, due to the lack of a schedule and the poor condition of the tracks and rolling stock. This paper aims to highlight some issues related to the operation of electric locomotives themselves. It has been established that the low productivity of electric locomotive haulage is also explained by poor adhesion of the locomotive wheels to the rails, that the operation of the electric locomotive itself does not correspond to the design data. The actual speeds of electric locomotives barely reach 50% of the speeds obtained from the engine characteristics, and the size of the train composition is much less than the calculated one. The article provides proposals for increasing the actual productivity of electric locomotives in mine conditions.
