Перепишите следующие предложения; подчеркните в каждом из них пассивную конструкцию. Переведите предложения на русский язык

1. Now power is transmitted to a great distance if it is carried by an electric current.

2. Dynamos and induction motors were designed at the end of the 19 th century.

3. A combination of electric lines and networks are being set up through the country.

4. Our power stations have been connected by high voltage transmission lines into several networks.

 

Перепишите следующие предложения; переведите их, обращая внимание на инфинитивные конструкции.

1. We won’t question how enough energy is drawn from the supply to bring an electric drill up to speed.

2. Everyone who tries the experiment will be wondering how such an effect can be used to make effective motors

 

Прочтите и устно переведите 1й абзац текста. Перепишите и письменно переведите 2й, 3й и 4й абзацы текста.

DC Motors

 

1.When current is passed through the armatureof a DC motor, a torque is generated by magnetic reaction, and the armature revolves. The revolution of the armature induces a voltage in the armature windings. This voltage is opposite in direction to the outside voltage applied to the armature, and hence is called back voltage or counter electromotive force (emf).

2. As the motor rotates more rapidly, the back voltage rises until it is almost equal to the applied voltage. The current is then small, and the speed of the motor will remain constant as long as the motor is not under load and is performing no mechanical work except that required to turn the armature.

3. Under load the armature turns more slowly, so it reduces the back voltage and permits a larger current to flow in the armature. The motor is thus able to receive more electric power from the supply and to do more mechanical work.

4. Because the speed of rotation controls the flow of current in the armature, special devices must be used for starting DC motors. When the armature is at rest, it has virtually no resistance, and if die normal working voltage is applied, a large current will flow, which may damage the commutator or the armature windings. The usual means of preventing such damage is the use of a starting resistance in series with the armature to lower the current until the motor begins to develop an adequate back voltage. As the motor picks up speed, the resistance is gradually reduced, either manually or automatically.

5. The speed at which a DC motor operates depends on the strength of the magnetic field acting on the armature, as well as on the armature current. The stronger the field, the slower is the rate of rotation needed to generate a back voltage large enough to counteract the applied voltage. For this reason the speed of DC motors can be controlled by varying the field current.

6) Прочитайте 5 абзац текста и выберите правильное утверждение;

The speed of a DC motor depends on

a) tile strength of the magnetic field acting on the armature

b) the armature current

с) both die armature field and current

 

КОНТРОЛЬНАЯ РАБОТА №2

Для того чтобы правильно выполнить контрольную работу необходимо усвоить следующие разделы курса английского языка:

1. Простые неличные формы глагола: Participle 1, Participle 2 в функциях определения и обстоятельства.

2. Герундий (Gerund) и его функции в предложении.

3. Атрибутивные группы и их перевод.

 

ВАРИАНТ 1

Перепишите следующие предложения; подчеркните в каждом из них Participle 1, Participle 2 и установите функции каждого из них в предложении, т.е. укажите, является ли оно определением, обстоятельством или частью глагола сказуемого. Переведите предложения на русский язык.

 

1. Raising the temperature we increase agitation of molecules.

2. Nearly all properties of matter are effected in some degree by temperature changes.

3. The insertion of an ammeter into a circuit must not change the magnitude of the current flowing.

4. The worked performed showed good results.

5. The substances that must have a long time to be heated will keep their heat much longer that those can be heated more rapidly.

 

Перепишите следующие предложения; подчеркните герундий и установите его функцию в предложении, т.е. укажите, является ли он подлежащим, дополнением, определением или обстоятельством.

1. By solving the problem of constructing the electron microscope were able to bring to view the fine structure of every material.

2. The most important way of changing mechanical energy into heat energy is by means of electricity.

3. Scientists have created special photo-cells capable of converting solar energy into electricity.