Hometask: Ex. 10, 15, 16.
The third class period
17 3
Listen to the sentences and define in each of them the meaning of the word “line”.
1. He was successful all along the line. 2. Unfortunately, his line of conduct is the line of least resistance. 3. His propositions were on the line. 4. It is difficult to draw a line between these two factors. 5. See whether the wheels are in line. 6. Drop me a line as soon as you possibly can.
18 6
Listen carefully to the tape-recorded text two times and render it in English using the words and word-combinations from the list: short circuit, to burn out, to locate, shorted point, leads of a test lamp, to move away, lamp will flicker, to remove the coils, to insert a strip of.
Short Circuit between Running and Starting Windings
A short circuit between these two windings will permit a current to flow through a part of the starting winding continuously while the motor is in operation, and in time will burn out the starting winding. To locate the shorted point, the windings are disconnected from the terminals and one of the leads of a test lamp (connected to the line) is connected to the running winding, and the other lead is connected to the starting winding. The lamp, will light, since current flows from the running winding through the shorted point to the starting winding. The starting winding is then moved away at various places in the stator. If the shorted point is moved, the lamp will flicker or go out. If the snorted point cannot be determined in this manner, it will be necessary to remove the coils of the starting winding one >-at a time until it is located.
The short circuit can usually be repaired by inserting a strip of varnished cambric in the slot between the two windings.
19 3
Work in pairs. Dwell upon the subject of the above text.
20 4__
Fulfil or explain the following:
1. List some of the duties of marine electricians.
2. Name some items of electrical equipment which are subjected to the supervision of electricians.
3. Prevent the fire from spreading.
21 4
Record your answers on a tape.
1. What must electricians know about electrical equipment?
2. Who arc they subordinated to?
3. When do they keep watches?
22 4
After listening to the texts choose a suitable title for each of them and give reasons for your choice. Say in what way these three texts differ and what they have in common.
A
On small motors only two wires are brought out of the motor for connection to the line. The field and armature connections are made internally. If the two wires are connected to the test leads, -the lamp should light and indicate a complete circuit. If the lamp does not light, the trouble may be caused by brushes not making contact with the commutator, a broken wire in the field, a broken connection between fields, a wire disconnected or broken on the brush holder. The same test may be used on large motors with external leads to field and armature.