Електротехнічний факультет

Варіант №2

Перепишіть речення та перекладіть рідною мовою. Визначте тип умовного речення.

2.1.1. This would not have been too much a problem if we had applied such atmospheres to presses and some forging machines.

2.1.2. If the cross-section of the conductor were slightly increased, it would cause the reduction of the resistance.

2.1.3. If an expedition to any other planet were possible it would result in highly important scientific data.

2.1.4. If the water falls from a great distance, its energy will be known to change from potential to kinetic.

2.1.5. They could have measured the voltage immediately, if they had connected a voltmeter to the circuit.

Поставте дієслово у дужках в потрібному часі, зважаючи на тип умовного речення. Перекладіть речення рідною мовою.

2.2.1. If I had money, I (to buy) that overcoat.

2.2.2. If you (to stay) here longer, you will see him.

2.2.3. If the goods had been loaded quickly, we (to receive) them in time.

2.2.4. If you (to arrive) earlier, you would have found me there.

2.2.5. We shall be very sorry if he (not to call) on us tonight.

Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на незалежний дієприкметниковий комплекс (The Absolute Participle Complex).

2.3.1. The sand being not open grained, the gases will not escape from the mould rapidly enough, and blowholes will be formed in the casting.

2.3.2. The groove having been cut at 45 degrees, all the difficulties were overcome.

2.3.3. Quantum generators can focus light in extremely narrow beams, their angular width being in the order of thousands of degree.

2.3.4. Plastics having been applied for interior decoration, we found them to be more practicable than some other materials.

2.3.5. The travelled distance having been given in meters and the time in seconds, speed was measured in m.p.s..

Перепишіть речення, перекладіть речення англійською мовою, вживаючи незалежний дієприкметниковий комплекс (The Absolute Participle Complex).

2.4.1. Навантаження двигуна зростає та ковзання, пропорційне до навантаження, має місце.

2.4.2. Цей завод виробляє багато чавуну, при цьому більша його частина переробляється на сталь.

2.4.3. Станок було вимкнено, та оператор залишив цех.

Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на об’єктний інфінітивний комплекс (Complex Object).

2.5.1. It is carelessness that allows losses to be greater.

2.5.2. We believed the programming to have been done very skillfully, so you might rely on the results to be exact.

2.5.3. The use of electric heating would enable all generators to be economically and efficiently serviced at a central depot.

2.5.4. I know gravity to act on every particle of a body so that its weight is actually distributed throughout the body .

2.5.5. We felt a good possibility utilize the new equipment for speeding up the process of calculation.

Перепишіть речення і перекладіть рідною мовою, звертаючи увагу на суб’єктний інфінітивний комплекс (Complex Subject). Перекладіть англійською мовою.

2.6.1. This house appears to have been built by a good architect.

2.6.2. This price was considered to be very high.

2.6.3. The rapid increase in viscosity was found to be relatively independent of the temperature.

2.6.4. He is certain not to come.

2.6.5. The goods are known to have been shipped by this vessel on the 15^th of May.

 

 

Перекладіть англійською, вживаючи об’єктний інфінітивний комплекс (Complex Object) та суб’єктний інфінітивний комплекс (Complex Subject).

2.7.1. Можливо, ці інженери не готові до роботи з напівпровідниками.

2.7.2. Відомо, що він виконав план достроково.

2.7.3. Ми вважаємо, що побудуємо трубопровід до кінця тижня.

2.7.4. Механік спостерігав, як двигун набирає обертів.

2.7.5. Здавалось, вони не помітили дефект корпуса.

Перепишіть текст за фахом та перекладіть його рідною мовою.

Електротехнічний факультет

Squirrel-cage motors

There are two types of AC motors, depending on the type of rotor used. The first is the synchronous motor, which rotates exactly at the supply frequency. The magnetic field on the rotor is either generated by current delivered through slip rings or by a permanent magnet.

The second type is the induction motor, which runs slightly slower than the supply frequency. The magnetic field on the rotor of this motor is created by an induced current. Most common AC motors use the squirrel cage rotor, which will be found in virtually all domestic and light industrial alternating current motors. The motor takes its name from the shape of its rotor "windings"- a ring at either end of the rotor, with bars connecting the rings running the length of the rotor. It is typically cast aluminum or copper poured between the iron laminates of the rotor, and usually only the end rings will be visible. The vast majority of the rotor currents will flow through the bars rather than the higher-resistance and usually varnished laminates. Very low voltages at very high currents are typical in the bars and end rings; high efficiency motors will often use cast copper in order to reduce the resistance in the rotor.

In operation, the squirrel cage motor may be viewed as a transformer with a rotating secondary. When the rotor is not rotating in sync with the magnetic field, large rotor currents are induced; the large rotor currents magnetize the rotor and interact with the stator's magnetic fields to bring the rotor almost into synchronization with the stator's field. An unloaded squirrel cage motor at rated no-load speed will consume electrical power only to maintain rotor speed against friction and resistance losses; as the mechanical load increases, so will the electrical load - the electrical load is inherently related to the mechanical load. This is similar to a transformer, where the primary's electrical load is related to the secondary's electrical load. Furthermore, a stalled squirrel cage motor (overloaded or with a jammed shaft) will consume current limited only by circuit resistance as it attempts to start. Unless something else limits the current (or cuts it off completely) overheating and destruction of the winding insulation is the likely outcome.

In order to prevent the currents induced in the squirrel cage from superimposing itself back onto the supply, the squirrel cage is generally constructed with a prime number of bars, or at least a small multiple of a prime number (rarely more than 2). There is an optimum number of bars in any design, and increasing the number of bars beyond that point merely serves to increase the losses of the motor particularly when starting.

Virtually every washing machine, dishwasher, standalone fan, record player, etc. uses some variant of a squirrel cage motor.

Дайте відповіді на запитання.

1. Why is the squirrel-cage motor named so?

2. What is the rotor made from?

3. Where do these motors find their application?

4. What device is it similar to?

5. What should one do to prevent the currents induced in the squirrel cage from superimposing itself back onto the supply?