Introduction. Thermosetting composite electric insulation of traction electric motors undergoes significant heating, moisture, overvoltage, vibration. Purpose. The substantiation of the possibility of using dielectric spectroscopy for monitoring the state of the hull thermosetting composite electric insulating system of induction traction motors (ITM) at the technological stage of manufacturing.. Methodology. In the induction traction motors in which the phases of the stator winding are connected to a «star» and do not have a zero point output, in the case of a two-electrode connection of one of the phases and the housing, the combined characteristics of the capacitance and the dielectric loss tangent of the three-phase hull insulation system are measured. Practical value. It is established that at the second resonant frequency near 10 kHz, the tangent of the dielectric loss is the most sensitive to the state of the composite ITM insulation. Dielectric spectroscopy at alternating voltage of the combined dielectric characteristics makes it possible to evaluate the state of the hull thermosetting electrical insulating system at the final stage of manufacturing of induction traction motors. References 9, tables 1, figures 4.

Introduction. Modern high-voltage systems for composite insulation of electrical machines consist of tape glass mica paper materials (dry or pre-impregnated). The electrical characteristics of a multilayer composite insulation system are determined by both the fractional content of the individual components and their electrophysical properties. Purpose. The analysis of the influence of electrophysical characteristics and thickness (fraction) of the dielectric barrier on the distribution of the electric field in the composite high-voltage insulation of electrical machines. Methodology. Simulation of surface charge accumulation at the interface between the substrate and the dielectric barrier is based on the Maxwell-Wagner theory for interfacial polarization. Practical value. The influence of the electrophysical characteristics and thickness of the dielectric barrier on the distribution of the electric field has been established. In the steady state, the electric field strength in the dielectric barrier exceeds the average value by 50 %. In the region of small transition times (up to 1 s), the relative dielectric constant of the barrier has a significant effect on the distribution of the electric field. The use of a dielectric barrier with a higher dielectric constant and fractional content in comparison with the substrate leads to an increase in electric field strength by 5 % relative to the average value in composite insulation. Experimental studies of the long-term electrical strength of glass mica-belt ribbons in the cured (thermosetting) state are consistent with the simulation results. Composite insulation based on glass fiber mica tape with a high content of the mica barrier and fiberglass of smaller thickness has (8-16) % higher values of long-term electric strength. References 9, figures 5.

A T-shaped equivalent circuit of an asynchronous phase motor with a deaf connection into the "star" of the stator winding phases is presented. The calculated and experimental frequency dependences of the quality factor of the "phase-phase" circuit as a function of the dielectric loss tangent of the cabinet insulation are given. It was found that at the resonant frequency in the inductance measurement mode, the characteristics of the electrically insulating system are significantly different in comparison with the measurement mode of the capacitance of the housing system of the electric machine. References 22, figures 4, table 1.

Introduction. Electrical insulation systems make up about 0.03 % of the traction electric machines (TEM) mass, but they are of exceptional importance and affect the design capabilities and manufacturing techniques of electric machines, ultimatelyon their specific weight and overall dimensions, on the reliability and durability of the TEM. Purpose. The monitoring of the stability of the manufacturing process of electrical insulating systems of the TEM based on the insulation resistance measurements. Methodology. The analysis of the manufacturing process is carried out for three versions of the case of insulation of the magnetic system of the DC traction electric motor. Practical value. Construction and analysis of special graphs (charts) of individual values and cumulative sums of insulation resistance, sliding range MR allow to find out whether the technological process of manufacturing electric insulating systems of traction electric machines is in a statistically controllable state. References 11, tables 1, figures 4. Key words: traction electrical machines, electrical insulation systems, insulation resistance, cumulative sum control chart, manufacturing process stability.Показано, что сопротивление изоляции может служить информативным параметром стабильности технологического процесса изготовления электроизоляционных систем тяговых электрических машин. Установлено, что сопротивление изоляции находится в пределах ±3σ относительно среднего значения каждой выборки трех вариантов исполнения электроизоляционной системы. Представлены контрольные карты индивидуальных значений и кумулятивных сумм сопротивления изоляции магнитной системы тяговых электродвигателей постоянного тока. Библ. 8, табл. 1, рис. 4. Ключевые слова: тяговые электрические машины, электроизоляционные системы, сопротивление изоляции, контрольные карты кумулятивных сумм, стабильность технологического процесса.

High-voltage insulation systems always have some background level of the partial discharges, which does not have any significant effect on the life of the electrical insulation design. At the same time, partial discharges destroy high-voltage insulation, leading to a carburization zone around the defect. This is the «hidden» period of development of the defect. The development of a defect zone, sooner or later, leads to an arc breakdown of the entire insulating gap. Purpose. The substantiation of the efficiency of detection of technological defects in high-voltage solid insulation of electrical insulating structures according to the characteristics of partial discharges. Methodology. The conditions for the occurrence of partial discharges in the thickness of the polymer insulation are considered. The possible values of the voltage of the beginning of partial discharges are determined for a model of a cylindrical air gap near the conductor of a power cable. It is shown that with the same applied voltages to highvoltage insulation, in the latter case, air inclusions of smaller thickness are activated in comparison with a flat structure. Practical value. The efficiency of detection of technological defects in solid composite case insulation of the stator winding of turbo-and hydrogenerators is shown. Based on the comparison of the amplitude of the pulses of partial discharges of positive and negative polarity, the estimated location of the technological defects in the insulation has been established. References 19, figures 7, table 1. Key words: technological defects, partial discharges, voltage of the start of partial discharges, glass-mica paper tape, amplitude of pulses of partial discharges, location of the defect. Визначено можливі значення напруги початку часткових розрядів для моделі циліндричного повітряного зазору поблизу струмопровідної жили силового кабелю. Показано, що при однакових прикладених напругах до високовольтної ізоляції в останньому випадку активізуються повітряні включення меншої товщини в порівнянні з пласкою конструкцією. На підставі результатів проведених випробувань силового кабелю на напругу 3 кВ встановлено, що грубі технологічні дефекти в товщі ізоляції відсутні. Амплітуда розрядів в повітряних включеннях не перевищує 10 пКл при прикладеній випробувальній напрузі 5 кВ частоти 50 Гц. Показана ефективність виявлення технологічних дефектів у твердої композитної корпусної ізоляції обмотки статора турбо-і гідрогенераторів. Встановлено, що в макетах, ізоляція яких виконана стрічками меншої товщини, технологічні дефекти розташовані в товщі ізоляції. Для макета, ізоляція якого виконана стрічками більшої товщини, технологічні дефекти у вигляді розшарування розташовані на кордоні розділу провідник-композитна ізоляція. Бібл. 19, табл. 1, рис. 7. Ключові слова: технологічні дефекти, часткові розряди, напруга початку часткових розрядів, склослюдопаперова стрічка, амплітуда імпульсів часткових розрядів, місце розташування дефекту. Определены возможные значения напряжения начала частичных разрядов для...