Lesson 6. Gyrocompass

1.Read the following words:

gyrocompass spinning axis fuse

gyroscopic synchronously alarm relay

auxiliary master aft

gimbal rheostat

2. Grammar. Инфинитив после подлежащего в качестве определения.

1) The engines to be used in space need to be very powerful.

2) The resistance to be reduced is a big figure.

3) The damage to be predicted may be associated with tension.

4) The experiments to lead to the practical applications are performed in the laboratory.

5) The phenomenon to be considered at the conference is a new one.

3. Read the following text: The Gyrocompass

The gyroscopic compass has two distinct advantages over the magnetic compass: first, it is entirely independent of the earth's magnetic field and all the technical tables, instruments, the measurements associated with it; second, it can be made to indicate the true geographical north instead of the magnetic north.

Unfortunately, it is a complicated mechanism, and in case of casualty it requires expert technical attention. Because of this, wherever gyrocompasses are used, magnetic compasses are still retained as auxiliaries.

The heart of the gyrocompass is the gyroscope which can be looked upon as a mass concentrated in a plane and spinning about an axis perpendicular to that plane. When placed in gimbal rings, it has three properties: first, three degrees of freedom; second, rigidity of plane; third, precession. The first property refers to the ability of a gyroscope to be rotated about any one of three mutually independent axes independently of the other two. These three axes are termed the spinning, the horizontal and the vertical axes. When the gyrocompass is operating normally, the spinning axis is parallel to the earth's surface and the meridian; the horizontal is parallel to the surface and the lines of latitude; the vertical points to the zenith.

By systems somewhat similar to those in gunnery fire control, headings of the master compass are synchronously transmitted to repeaters which, in external appearance, look like the magnetic compass and are placed at all points on the ship where the knowledge of the ship's heading is a necessity. On the largest naval ships there may be dozens of these.

The main equipment of a gyrocompass installation consists of the master compass and its supports; batteries in case of failure of ship's supply voltage; one or two small motor generator sets for supplying other than ship's voltages to the compass; a panel for instruments, switches, rheostats, fuses and alarm relays; and a panel for fuses and switches for the repeaters. The large naval ships have two master compasses, one forward and one aft; smaller ships have one.

4. Words to be learnt:

gyroscopic compass – гирокомпас

gimbal ring – звено универсального шарнира

degree of freedom – степень свободы, степень подвижности

rigidity of plane – устойчивость самолета

precession – прецессия

master compass – главный компас

alarm relay – сигнальное реле

EXERCISES

1. What's the Russian for:

gyrocompass, entirely independent, to indicate, instead of, in case of casualty, auxiliary, to spin, perpendicular, gimbal, rigidity, precession, spinning axis, synchronously, rheostats, fuses, alarm relays, switches, repeaters, aft.

2. Answer the following questions:

1) What are two distinct advantages of the gyrocompass over the magnetic

compass?

2) Is it a complicated mechanism?

3) What is the heart of the gyrocompass?

4) What is the first property of a gyroscope?

5) What does the main equipment of a gyrocompass installation consist of?

3. Match words with their meanings.

Gyroscope	—	it indicates the true geographical north.
Precise	—	it indicates the true magnetic north.
Magnetic compass	—	the heart of the gyrocompass.
Gyrocompass	—	apparent line that separates earth from sky.
Horizon	—	accurately expressed, exact in statement.
Magnet	—	substance able to attract iron.