Самостійна робота № 13

Тема: Components of the engine

Завдання: переписати текст “ Components of the engine ” в зошит, письмово його перекласти використовуючи активну лексику тексту. Відповісти на запитання.

reciprocating parts- поршневі частини

within- в; в межах

camshaft- розподільний вал

crankshaft- колінчастий вал

reciprocating motion - зворотно-поступальний рух

rotary motion - обертальний рух

Components of the engine

The internal combustion engine has reciprocating parts: pistons, rings, valves and connecting rods. These parts cause engine vibration.

The piston moves up within the cylinder. The piston head receive the force from the combustion of oil within the cylinder.

The piston has four rings. Three rings are at the head of the piston and provide good compression. One ring is at the bottom of the piston. It controls the cylinder lubrication.

The engine has valves. They are intake valves and exhaust valves. Intake valves allow the fuel to enter the combustion chamber. Exhaust valves allow the gases to pass from the combustion chamber. So the valves open and close the combustion chamber where the burning of fuel takes place. A camshaft opens each valve.

The connecting rod links the pistons and the crankshaft. It changes the reciprocating motion of pistons into the rotary motion of the crankshaft.

Answer these questions:

1. What are the reciprocating parts?

2. Where does the piston move?

3. How many rings does the piston have?

4. What opens each valve?

5. What does the connecting rod link?

Самостійна робота 14

Тема: The direct-current machine

Завдання: переписати текст “ The direct-current machine ” в зошит, письмово його перекласти використовуючи активну лексику тексту. Відповісти на запитання.

alternating current – перемінний струм

direct-current – прямий струм

armature – якір

pole – осердя

winding - обмотка

The direct-current machine

Electrical machines are divided into alternating current (a. c.) and direct-current (d. c.) machines. The basic parts of a d. c. machine are the armature and electromagnets (or field coils). Coils wound on the pole cores form the excitation field of the machine. The armature is the rotating part of the machine. In its insulated slots is placed a winding connected to the commutator. Carbon brushes are placed in brush holders and contact the rotating commutator.

There are two electric circuits in the d. c. machine, the armature circuit and the excitation circuit. A d. c. machine is reversible: if the machine is rotated and the magnetic field is excited the machine sends a direct current into the external circuit through the commutator and brushes: the machine operates as a generator. If the armature and excitation winding are joined to a d. c. circuit the armature runs and the machine operates as a motor and converts electrical energy into mechanical energy.

Answer these questions:

1. What are the types of electrical machines?

2. What are the basic parts of a direct – current machine?

3. Where are carbon brunches placed?

4. A direct – current machine is reversible, isn’t it?

5. When does the machine operate as a motor?