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ТЕХНИЧЕСКИЕ НАУКИ
APPLYING THE NON-CONTACT DEVICES FOR STARTING A SINGLE-PHASE ASYNCHRONOUS ELECTRIC MOTOR Bobаzhanov M.K.1, Fayziev M.M.2, Mustaev R.A.3, Babaev O.E.4,Toshturdiev Sh.E.5 Email: Mustaev6114@scientifictext.ru
1Bobazhanov Maksud Kalandarovich - Doctor of Technical Sciences, Professor, Department of Power Supply, Tashkent State Technical University I.A. Karimov, Tashkent; 2Fayziev Makhmanazar Mansurovich - Candidate of Technical Sciences, Associate Professor; 3Mustaev Ruslan Aktamovich - Applicant, Assistant; 4Babaev Otabek Elmurodovich - Applicant, Assistant; 5Toshturdiev Sherbek Erkinovich - Undergraduate, DEPARTMENT OF ELEKTRIC POWER ENGINEERING, FACULTY OF ENERGY, KARSHI ENGINEERING ECONOMIC INSTITUTE, KARSHI, REPUBLIC OF UZBEKISTAN
Abstract: the article discusses the functions of non-contact devices to start an electric motor, using contactless devices as well as communication with automation systems. These functions meet the most common applications, mainly in the economic industries for centrifugal pumps and other machinery. The motor starting control circuit provides high reliability, safety and ease of commissioning. The control and starting circuit of the electric motor provides high reliability, safety and ease of commissioning. At present, non-contact devices for starting and braking electric motors are widely used in an unregulated AC drive. Their use has indicated a steady trend of transition from the usual contact switching of stator circuits of asynchronous electric motors to contactless switching. Keywords: start-up, using contactless devices, electric motor, step-down transformer, rheostat, diode, thyristor, voltage, thermal relay, voltmeter, ammeter, signal lamp.
ПРИМЕНЕНИЕ БЕСКОНТАКТНЫХ УСТРОЙСТВ ДЛЯ ПУСКА ОДНОФАЗНОГО АСИНХРОННОГО ЭЛЕКТРОДВИГАТЕЛЯ Бобажанов М.К.1, Файзиев М.М.2, Мустаев Р.А.3, Бабаев О.Э.4,
Тоштурдиев Ш.Э.5
1Бобажанов Максуд Каландарович - доктор технических наук, профессор, кафедра электроснабжения, Ташкентский государственный технический университет им. И.А. Каримова, г. Ташкент; 2Файзиев Махманазар Мансурович- кандидат технических наук, доцент; 3Мустаев Руслан Актамович - соискатель, ассистент; 4Бабаев Отабек Элмуродович - соискатель, ассистент; 5Тоштурдиев Шербек Эркинович - магистрант, кафедра электроэнергетики, энергетический факультет, Каршинский инженерно-экономический институт, г. Карши, Республика Узбекистан
Аннотация: в статье рассматриваются функции бесконтактных устройств для запуска электродвигателя с использованием бесконтактных устройств, а также связь с системами автоматизации. Эти функции подходят для наиболее распространенных приложений, в основном в экономических отраслях для
центробежных насосов и другого оборудования. Схема управления пуском двигателя обеспечивает высокую надежность, безопасность и простоту ввода в эксплуатацию. Схема управления и пуска электродвигателя обеспечивает высокую надежность, безопасность и простоту ввода в эксплуатацию. В настоящее время бесконтактные устройства пуска и торможения электродвигателей широко используются в нерегулируемом приводе переменного тока. Их использование указывает на устойчивую тенденцию перехода от обычного контактного переключения цепей статора асинхронных электродвигателей к бесконтактному переключению.
Ключевые слова: пуск, с применением бесконтактных устройств, электродвигатель, понижающий трансформатор, реостат, диод, тиристор, напряжение, тепловое реле, вольтметр, амперметр, сигналная лампа.
Introduction. Currently, non-contact devices for starting and braking electric motors are widely used in an unregulated AC electric drive, the element base for the construction of which is a large range of power controlled semiconductor devices (thyristors and triacs) and various hybrid modules based on them. Their use has indicated a stable trend of transition from the usual contact switching of stator circuits of asynchronous electric motors to contactless in a number of complete drive devices. [1] Important advantages of non-contact devices in comparison with contact devices are the following: fast response, high speed and switching frequency. The inertia of the moving parts of contact devices (especially power ones) limits their speed. There are no moving parts in contactless devices. Therefore, the switching time of non-contact devices is usually several orders of magnitude less than contact ones; [2] The following article [3] presents a scheme of changing one half-cycle of alternating sinusoidal current. In this case, the startup of the device is not fully adjusted. [4] Creating a cost-effective circuit that allows the full cycle of the sinusoidal current to be adjusted. Tasks to be solved: drawing up the circuit, checking, testing the device in the laboratory and getting the result. [5]
Method. We offered a contactless starter for starting electric motors up to 5 kW. The starter circuit show in Figure. 1, which works in the following order:
A step-down transformer (220/12 V) is connected through thyristor elements to start a single-phase electric motor. In the circuit, the transformer is connected through a diode bridge and from the diode bridge the electric motor is connected through a thyristor. The electric motor is protected by thermal relays. The phase of the circuit is connected to the thyristor. A reliable electric motor control circuit, that is, starting and braking, is a thyristor switching circuit that provides starting and stopping of three-phase asynchronous motors, protection of mechanisms and motors, as well as communication with automation systems. The induction motor start controls provide high reliability, safety and ease of commissioning.
When a sinusoidal voltage is applied to the phase asynchronous motor, shown in Figure. 2, the circuit equation has the form:
Fig. 1. Scheme for starting an induction motor (up to 5 kW) with thyristor elements.
Accepted designations: L - phase; N - zero; Rт - normal closed contact of the thermal relay; Tr-1 transformer 220/12 V; VS -1, VS -2 diode bridge; resistor R = 10 kOhm; R -variable resistor WH 148 100 kOhm; VD -1, VD -2 - diodes; T - thyristor T 132-50-16; ED - Electric motor.
Fig. 2 Asynchronous motor connected to sinusoidal voltage
uB + + Lн ^ = UmsinMt and ив + ин = и,
(1)
Where:
uB-voltage drop across the thyristor
uH- voltage across the load
uc- applied instantaneous voltage in the circuit
iH- load current
LH- Load inductance
RH- Active load resistance
Um- applied amplitude voltage in the circuit
Expression (1) is non-linear due to the non-linearity of the current-voltage characteristic of the thyristor and can be replaced by two linear ones.
¿hRH + LH ^H = UmSinUt (2) With iH ^ 0 and a forward voltage drop across the thyristor uB « 0 (assumption of the ideality of the device).
Obviously, when switched on, due to the presence of inductance, the current does not change abruptly and is represented by two components:
i = i' + i'
(3)
Where:
¿-phase current asynchronous motor ¿'-periodic component
i' =-f sin (ot - p) (4)
Where:
Z-total circuit resistance, Z = jR2 + (o LH )2 ®-load shear angle p = arc tg — i' '-aperiodic component
i'' = A e~T (5)
Where:
A-is the constant of integration, determined by the initial conditions T-electromagnetic constant of the IM phase
T = f (6)
Rh
Taking into account that o T = = -^=tgm expression (5) will take the form:
Rh RH
(i)t-a
i'' = A (7)
Where:
a- values of the control angle
Based on expressions (4) and (7), the final expression for the current of the asynchronous motor phase will take the form:
' u at~"
i = -fsin (ot -p)+Ae tb<p (8)
Results and discussion. In different industries, a large number of electric motors are used to drive various mechanisms. [6] The economic sectors of the Republic of Uzbekistan categorically cannot be considered without the use of electric motors, including starting electric motors using contactless devices. [7] For their start-up and switching at the present time, magnetic starters, contactors, electromechanical relays, etc. [8]
All industrial enterprises today and electrical equipment of all systems of economic sectors and widely used elements in the control of devices: magnetic starters, electromechanical relays and other devices. The total power of these devices is from 30 to 100 VA, the number in the energy and other industries is very large, this is felt when electricity is consumed in operation. When operating small-scale synchronous and asynchronous motors, there are several problems for specialists to solve this problem. They are constantly in operation, including a huge part of the electricity they use from the electrical network [9].
Fig. 3. Virtual scheme
To regulate the current, the control circuit is equipped with control rheostats. This enables the flowing power from minimum to operating power. If the current exceeds the rated value, the thermal relay disconnects the control circuit and. the electric motor is disconnected from the mains [10].
Osdlloseope-XSCI X
Fig. 4. The current shape of the circuit Conclusion. It is an economical solution that allows you to:
- to reduce the cost and operation of mechanisms by reducing mechanical stress and improving the availability of equipment.
- during operation, rational use of fuel and energy resources and competitive elements from the used fuel;
- rational use from electrical equipment working up to today;
- categorically not to allow the running of electric devices to run, and, including its load, should not be reduced to 70%;
- to reduce the loss of electricity in electrical devices and electrical equipment;
- to reduce the loss of electricity by several elements used in the control of electrical devices.
To date, research and develop a low-power, low-power, including low-noise, compact and, it's time to move to a reliable one in the composition of contactless elements with controlled devices.
The composition uses thyristors, very little power consumption, during operation it is noiseless, reliable and works well.
References / Список литературы
1. Andreev V.A. "Relay protection and automation of power supply systems". M.: "High School", 1991.
2. Kulanovsky Y.S. "Thyristor setting". Publishing house Radio and communication. M., 1987.
3. Rozanov Y.K., Ryabchitsky M.V., Kvasnyuk A.A. Power Electronics 2nd edition, stereotyped Moscow Publishing House MPEI, 2009.
