- •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
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Memorize the words and word combinations and their equivalents.
squirrel cage induction motors – коротко замкнутий асинхронний двигун, асинхронний двигун з білячою кліткою
variable – змінний, регульований
converter – перетворювач
variable voltage variable frequency (VVVF) converter – перетворювач з регульованою напругою і частотою
variable speed drive (VSD) – привід змінної швидкості
technique – метод
design – розробляти, конструювати, проектувати
automated – автоматизований
frame – рама, станина, корпус, конструкція
performance characteristics – робочі (експлуатаційні) характеристики
reliability – надійність
DC motor – двигун постійного струму
bearing– підшипник
slipring – контактне кільце
brush – колекторна щітка
pre-lubricate – заздалегідь змазувати
single-phase – однофазний.
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Read and translate the text.
For industrial and mining applications, 3-phase AC induction motors are the prime movers for the vast majority of machines. These motors can be operated either directly from the mains or from adjustable frequency drives. In modern industrialized countries, more than half the total electrical energy used in those countries is converted to mechanical energy through AC induction motors. The applications for these motors cover almost every stage of manufacturing and processing. Applications also extend to commercial buildings and the domestic environment. They are used to drive pumps, fans, compressors, mixers, agitators, mills, conveyors, crushers, machine tools, cranes, etc. It is not surprising to find that this type of electric motor is so popular, when one considers its simplicity, reliability and low cost.
In the last decade, it has become increasingly common practice to use 3-phase squirrel cage AC induction motors with variable voltage variable frequency (VVVF) converters for variable speed drive (VSD) applications. To clearly understand how the VSD system works, it is necessary to understand the principles of operation of this type of motor.
Although the basic design of induction motors has not changed very much in the last 50 years, modern insulation materials, computer based design optimization techniques and automated manufacturing methods have resulted in motors of smaller physical size and lower cost per kW. International standardization of physical dimensions and frame sizes means that motors from most manufacturers are physically interchangeable and they have similar performance characteristics.
The reliability of squirrel cage AC induction motors, compared to DC motors, is high. The only parts of the squirrel cage motor that can wear are the bearings. Sliprings and brushes are not required for this type of construction. Improvements in modern pre-lubricated bearing design have extended the life of these motors.
Although single-phase AC induction motors are quite popular and common for low power applications up to approx 2.2 kW, these are seldom used in industrial and mining applications. Single-phase motors are more often used for domestic applications.
The information in this chapter applies mainly to 3-phase squirrel cage AC induction motors, which is the type most commonly used with VVVF converters.