Антиплагиат (Разработка мероприятий по снижению числа отказов тяговых двигателей электровозов 2(3)ЭС5К), страница 3

As a result, the load fluctuations cause the movement of bars relative tothe walls of the cutouts, which causes the isolation to break if it malojelastichna.electric field in high voltage electrical vehicles causes local electricity and ionization of internal and externalair (gas) incorporation. The ionization of aerial inclusions entails: an increase in thermal losses in isolation;Mechanical stratification of mica sheets; The emergence of ozone and nitrogen oxides which, when moistureis available, form azotistuju and even nitric acid.Ozone, being sufficiently strong oxidant, causes the destruction of the parts of isolation.

Nitrogen andnitrogenous acid have effects not only on insulation, but also on metallic elements (steel, copper). Thespecial damage to the ionization is a domestic inclusion. The phenomenon of surface ionization (bonding)appears due to the air gap between the insulation surface and the groove walls. Pretreatments is much lessdangerous than inner ionization, because only the surface layers of isolation are exposed to its destructiveactivity. The presence of local sliding electric shocks in the form of sparks that can cause the splitting ofmica and other parts of the insulation is much more dangerous.

For the purpose of preventing surfaceelectrical bits, the exterior insulation is manufactured with Poluprovodjashhim coating. The capabilities ofthe cutouts and the coil surface are aligned [2].Higher humidity reduces the electrical resistance to insulation, which in turn increases leakage and electricallosses in isolation. In general, however, this deterioration of insulation properties is not critically reversibleand can be corrected by slow dryer. Typically, dried insulation, including a low-voltage or short-circuitedfree machine, i.e. no load. In the case of accelerated drying, insulation may be damaged due to theincreased allocation of the water vapour from the interior, causing cracks in isolation and making it porous.Mechanical effects applied to insulation, due to the power dynamics between the conductor, the internalvibration, the centrifugal forces of the parts of the revolved T.

P. at times, the insulation is exposed tostrong mechanical forces and external effects (for example, traction motors, train electric vehicles).Repeated efforts made by the conductor are causing deformation in isolation, reducing its electricalstrength.In addition to the cited underlying causes, the ageing of isolation may accelerate a number of other factors:presence of chemically active substances in the air (e.g. chlorine, ammonia, acid and alkaline vapours),water, reduced temperatures (up to-60 ° C in some parts of the country), micro-organisms and sometimeseven insects (in tropical countries).The reasons given lead to a situation in which the term of the correct isolation service is generally notmore than 20 years.

At the end of this time period, the risk of failure of the insulation and the failure of anelectric vehicle generally makes it impossible for the vehicle to continue to operate without a major overhaulor a complete replacement.1.2 Круговой огонь и его причиныDuring the operation of the DC electric vehicle, the manifolds sometimes have an electrical arc or a largenumber of small electrical bits. This phenomenon is referred to as a circular fire [3].The main reason for the occurrence of a circular lamp is an excessively high voltage between the adjacentplates.

During the period of operation, the insulation between the neighboring collector plates is subjectedto coal dust and small brush fragments, which can result in the closure of the plates, forming "bridges".In low-capacity power plants where the anchoring sections have a sufficiently high active resistance, as wellas induction, the bridges are ignited in a short flow, and the phenomenon of the circular lamp is sufficientlyharmless. In such a case, there is a slight restatement in the reservoir, sometimes referred to as a potentialbias, as it is caused by the high difference in capabilities between the neighboring plates of the manifold.With a larger fusing, adjacent plates are formed, resulting in the formation of craters of 2-3 mm diameter,and the so-called flashes are created on the manifold. This phenomenon is more dangerous because thedamaged edges of the manifold plates cause the brush to wear more quickly, and at times they arecompletely destroyed.In high-power and medium-and small-capacity vehicles with elevated voltages between adjacent collectorplates, the circular fire is a powerful electric arc of the manifold.

This arc overlaps a sufficiently large portionof the reservoir, and sometimes even closes a short brush of the different polarity (the block overlap). Theappearance of a powerful arc on the manifold is accompanied by a strong light and sound effect (in largemachines This may be a bomb explosion). The high anchor current that occurs when the manifold is closedcauses the protection and wear of the surface of the collector, the insulators, the brush holders, and so on,which means that the machine fails.

The pattern of the circular fire on the manifold is shown in Figure 1.1[3].Рисунок 1.1 – Схема возникновения кругового огня на коллекторе и зависимостьпредельно допустимых напряжений 68 Uк mах от коллекторного деления tк: 1 – первичная дугапри замыкании смежных коллекторных пластин; 2 – газы и пары меди; 3 – мощная дуга 68In order to reduce the likelihood of a circular lamp, the maximum difference in potential between adjacentcollector plates should be reduced. Figure 1.1 shows the maximum values of these stresses (with varyingthickness of дiz insulation between the manifold plates) which should not be exceeded during operation.Such data are medium-static and, of course, need to be refined for each specific model of the machine as aresult of the tests.In order to reduce the maximum voltage between the adjacent collector plates in large electric vehicles, theanchors of the Odnovitkovymi partitions (WC = 1) are used.

Demote the average voltage between themanifold plates to 15-18 V (also limiting the active length of the anchor) and take measures to reduce thedistorting effects of the anchor, i.e. induction of vmah. The easiest way out is to reduce the vmah byincreasing the air gap, which means that the DC machine is usually performing with a sufficiently large airgap than the asynchronous one. At the same time, an increase in the air gap requires an appropriateincrease in the magnetomotiveing force of the excitation (to create a sufficient magnetic flux), which in turnincreases the size of the entire vehicle.It is most advantageous to use an air gap that is small under the midpoint of the pole and that grows to itsedges, where the magnetomotiveing force of the anchor grows.

At the same time, magnetic resistance tothe flow of the main poles increases to a much lesser extent than for the thread generated by thetransverse reaction of the anchor. As a result, the widening gap requires a lesser increase in themagnetomotive of the excitation winding force than even.A more drastic measure may be the use of compensatory winding (figure 1.2), which is located in thegrooves of the main poles and connected with the winding of the anchor sequentially. The compensationwinding shall be included so that the by magnetomotive force of the F to was directed to themagnetomotive force of the anchor of the FAQ and compensated for its effect. In F to = magnetomotive,the anchor force does not actually distort the magnetic field in the air gap.

The compensation winding is amajor complication for the design of the electric vehicle, so that it is used exclusively in medium and highcapacity vehicles operating under difficult conditions (frequent launches, load-currents, congestion, etc.).The compensatory winding shall also apply when the vehicle is designed with strict position limits, as thiswinding reduces the air gap and therefore the dimensions of the excitation winding [3].Рисунок 1.2 – Принципиальная схема (а) и схема расположения в машине (б)компенсационной обмотки: 1 – главный полюс; 2 – обмотка возбуждения; 3 –компенсационная обмотка; 4 – добавочный полюс; 5 – обмотка добавочного полюса; 6 –якорь 68Statistics on non-scheduled repairs due to the failure of elements of the electrical part of tractionmotors at the depot of Khabarovsk-2 are shown in table 1.1, and its graphic presentation in the form of achart in Figure 1.3.1.3 Статистика отказовСведения по отказам элементов электрической части тяговыхэлектродвигателей для анализа взяты в сервисном локомотивном депо 91«Дальневосточное».

Данные об этом приведены в таблице 1.1.Таблица 1.1 – Статистика по неплановым ремонтам по причине отказовэлементов электрической части тяговых электродвигателей по депо Хабаровск-2за 2016 год.Наименование видадвижения1ПоказателиЯнварь Февраль Март АпрельКоличество, шт. 2 24 10 18 3Время простоя в ремонте, час 3 470 214 212 152Продолжение таблицы 1.11Показатели, 104 т∙км.бруттоМай Июнь Июль Август Сентябрь Октябрь2 2 5 10 34 34 573 31,5 57 271 495 396 765Окончание таблицы 1.11Показатели, 104 т∙км.бруттоНоябрь Декабрь2 47 363 854 771Рисунок 1.3 – Диаграмма неплановых ремонтов по депо Хабаровск-2 за 2016 год.2 РАБОТА СИЛОВОЙ СХЕМЫ В РЕЖИМЕ ТЯГИ И ТОРМОЖЕНИЯ2.1 Регулирование напряжения на тяговых двигателях в режиме тягиFor ease of reference in Figure 2.1, the simplified power scheme of the traction drive is shown, withnumbers 1 to 8 showing the VIP shoulders, 1-III of the section of the traction winding transformer.