- •Memorize the words and word combinations and their equivalents.
- •Find the words and combinations of words in the text and translate the sentences containing them.
- •Read and translate the text.
- •Translate the word combinations from the text:
- •Point out the sentences in the text in which the word “to make” should be translated as “примушувати”.
- •Answer the questions.
- •Find the sentences in the text telling you about two problems facing the simple two pole dc motor. Text b Compensation for stator field distortion
- •Make sure that you know these words and word combinations.
- •Read and translate the text.
- •Answer the questions.
- •Text c Dynamo Design Variations
- •Read and memorise the words and word combinations.
- •Permanent magnet motor – двигун з постійним магнитом
- •Read and translate the text.
- •Answer the questions.
- •Listen to the words and word combinations from the text. Pay attention to their meaning.
- •Memorize the words and word combinations and their equivalents.
- •Read and translate the text.
- •Match the words and word combinations (a-e) to the sentences (1-5)
- •Answer the questions to the text
- •Say if the statement to the text is true or false
- •Translate the sentences paying attention to Indefinite Tenses in Active and Passive. Correct the mistakes in the sentences.
- •Text b Basic construction
- •Listen to the words and word combinations from the text. Pay attention to their meaning.
- •Memorize the words and word combinations and their equivalents
- •Read and translate the text
- •Match the words and word combinations (a-e) to the sentences (1-5)
- •Answer the questions to the text
- •Say if the statements to the text are true or false
- •Translate the sentences paying attention to Indefinite Tenses in Active and Passive. Correct the mistakes in the sentences.
- •Text c Principles of operation
- •Listen to the words and word combinations from the text. Pay attention to their meaning.
- •Find the words and combinations of words in the text and translate the sentences containing them.
- •Memorize the words and word combinations and their equivalents.
- •Read and translate the text
- •Match the words and word combinations (a-f) to the sentences (1-6)
- •Answer the questions to the text
- •Define the functions of Participle I and Participle II in the following sentences
- •Say, which of the sentences are in the Active and which are in the Passive Voice
- •Translate the sentences paying attention to the Sequence of Tenses
- •Translate the following Conditional sentences
- •Transformer Text a
- •Read and memorize words and word-combination
- •Make sure that you know these words and word combinations.
- •Read and translate the text.
- •Math the following English words with the Ukrainian ones.
- •Find English equivalents to the words:
- •Translate the word combinations from the text:
- •Answer the questions to the text.
- •Text b Operation at different frequencies
- •Read and memorize the words and word-combinations
- •Be sure that you know these words
- •Read and translate the text.
- •Text c Limitations
- •Make sure that you know these words and word combinations.
- •Read and translate the text.
- •Find the equivalents to the following.
- •Text d Construction
- •Read and memorise the words and word combinations
- •Read and translate the text. Cores
- •Find the equivalents to the folloving English words:
- •Point out English equivalents to the words:
- •Translate the word combinations.
- •Answer the questions.
- •Read the passage about steel cores. Retell it. Text e Windings
- •Listen to the words and word combinations from the text and memorize them.
- •Read and translate the text.
- •Match the English words and word combinations with the Ukrainian ones.
- •Insulation of windings
- •Text g Shielding
- •Supplement Speed control
- •Dc motor starters
- •Shielding
- •Autotransformers
- •Voltage transformers
- •Pulse transformers
- •3 Phase electrical power Transformer
- •3 Phase Transformer Delta and Wye Connections
- •Перелік скорочень
Text c Limitations
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Read and memorize the words and word-combination.
limitation – обмеження
convert – перетворювати
vice versa – навпаки
dissipate – розсіюватись
copper loss – втрати в міді, втрати в обмотці
attributable – властивий
iron loss – втрати у сердечнику
plug-in – вставний
power brick – блок живлення
proximity effect – вплив близкості зворотного (сусіднього) провода
additional – додатковий
eddy currents – вихрові струми
induce – індукувати
circulate – циркулювати
cause – викликати, заставляти
resistance – опір
resistive – резестивний
silicon – кремній
aging – старіння
hysteresis losses – гістерезисні втрати, втрати на гістерезис
reverse – змінювати напрямок на зворотний
magnetostriction – магнітострикція
expand – розширювати(сь)
contract – взаємодіяти
buzzing – дзижчання
friction – тертя
susceptible – чутливий.
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Make sure that you know these words and word combinations.
mechanical losses – втрати на механічні процеси
fluctuate – коливатись
incite – збуджувати
vibration – коливання
humming – гул
consume – споживати
stray losses – паразитні втрати
intercept – перехоплювати
leakage flux – потік розсіювання
support structure – несуча конструкція
cooling – охолодження
cooling fan – охолоджуючий вентилятор
oil pump – масляний насос
water-cooled heat exchanger – теплообмінник з водяним охолодженням
load-dependent (load-losses) – втрати у трансформаторі під навантаженням
no-load loss – втрати у режимі холостого ходу
dominate – впливати
eddy current losses – втрати на вихрові струми
contribute – сприяти.
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Read and translate the text.
Transformers alone cannot do the following:
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Convert DC to AC or vice versa
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Change the voltage or current of DC
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Change the AC supply frequency.
However, transformers are components of the systems that perform all these functions.
Energy losses An ideal transformer would have no losses, and would therefore be 100% efficient. In practice, energy is dissipated due both to the resistance of the windings known as copper loss or I2R loss, and to magnetic effects primarily attributable to the core (known as iron loss). Transformers are, in general, highly efficient: large power transformers (over 50 MVA) may attain an efficiency as high as 99.75%. Small transformers, such as a plug-in "power brick" used to power small consumer electronics, may be less than 85% efficient.
Transformer losses:
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Winding resistance. Current flowing through the windings causes resistive heating of the conductors (I2 R loss). At higher frequencies, skin effect and proximity effect create additional winding resistance and losses.
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Eddy currents. Induced eddy currents circulate within the core, causing resistive heating. Silicon is added to the steel to help in controlling eddy currents. Adding silicon also has the advantage of stopping aging of the electrical steel that was a problem years ago.
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Hysteresis losses. Each time the magnetic field is reversed, a small amount of energy is lost to hysteresis within the magnetic core. The amount of hysteresis is a function of the particular core material.
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Magnetostriction. Magnetic flux in the core causes it to physically expand and contract slightly with the alternating magnetic field (producing a buzzing sound), an effect known as magnetostriction. This in turn causes losses due to frictional heating in susceptible ferromagnetic cores.
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Mechanical losses. In addition to magnetostriction, the alternating magnetic field causes fluctuating electromagnetic forces between the primary and secondary windings. These incite vibrations within nearby metalwork, creating a familiar humming or buzzing noise, and consuming a small amount of power.
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Stray losses. Not all the magnetic field produced by the primary is intercepted by the secondary. A portion of the leakage flux may induce eddy currents within nearby conductive objects, such as the transformer's support structure, and be converted to heat.
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Cooling system. Large power transformers may be equipped with cooling fans, oil pumps or water-cooled heat exchangers designed to remove the heat caused by copper and iron losses. The power used to operate the cooling system is typically considered part of the losses of the transformer.
Losses may be either load-dependent('load-losses') or independent of it ('no-load loss'). Winding resistance dominates load-losses, whereas hysteresis and eddy currents losses contribute to over 99% of the no-load loss.