6. It will hardly be possible for them to solve this problem. 7. It will be easy for the trained technician to locate the fault. 8. They waited for the experiment to be continued. 9. Automatic control permits this process to be sped up.
In the blanks below insert the proper form of verbs given in Russian in brackets. The text concerns the theory of electron tube.
1. The part of some devices ... in electronic control . . . the electron tube (используемых, является).
2. Like those ... in radios, it ... of a glass or metal envelope that . . . several electrodes (используемым, состоит, включает).
3. The simplest tube . . . the diode, which ... of two electrodes, an anode or plate, and a cathode (есть, состоит).
4. For this tube . . . , it ... necessary that electrons . . . (работала, есть, эмиссировались).
5. This . . . so . . . that it . . . a course of electrons when it . . . (сконструирован, может стать, нагревают).
6..........the electrons (нагревание стремится освободить).
7. Some cathodes . . . like the filament of an incandescent lamp with an . . . coating of a material, which ... a large number of electrons while the filament ... hot (делают, дополнительный высвобождает, есть).
8. The tube......after the . . . material . . . by long use (прекратит
действовать, покрывающий, испарится).
9. Some tubes ... a cathode that ... indirectly (имеют, нагревают).
10. ... useful, the electrons that . . . from the cathode . . . , otherwise they . . . simply . . . around in space or . . . cathode (чтобы быть полезными, испускаются, должны быть собраны, будут разноситься, вернутся).
11. The electrons ... by the anode when it ... a positive charge on it (будут собираться, имеет).
12. The anode ... to the positive terminal of a battery . . . the electrons . . . quickly to the anode and ... a current . . . through the empty space between the anode and cathode (подключается, заставляя, двигаться, заставлять, протекать).
18 15
Ноте exercise. Write a letter to a firm requesting delivery of an electric equipment set. Don’t forget to include all the information concerned. Note that you expect delivery at the specified dates and on usual terms.
19 20
Home exercise. Rephrase the indirect instructions from the text below in a direct way where it is possible.
Model. The megger reading may be well within the prescribed parameters for the motor to be started. — Follow the prescribed parameters of the megger readings while starting the motor.
Be prepared to dwell on the subject with your electrician.
An in-Situ Method of Drying out Electrical Machinery*
It is interesting to note that a quiz for junior engineers asked the question: “What is the reason for the most frequent cause of breakdowns in electrical equipment?” The answer was: “The failure of insulation due to salt and moisture ingress”.
The ingress of moisture to electrical equipment at certain locations on board ship is almost inevitable.
It follows, therefore, that any piece of electrical repair equipment which can, in the first instance, be used preventively, that is to ensure that motors and cables are kept free of moisture, and, in the second
role, can repair equipment which has been subjected to total flooding, should be a wise investment. Preventive maintenance. The special equipment is designed to resist dampness in electrical equipment by keeping the installation at a temperature a few degrees above its surroundings. This means that any motor present will be removed without damaging the equipment.
The 2 kVA, 400 mmX400 mmX510 mm transformer is normally placed at the main switchboard. It has 8 secondary voltage tappings from 2 to 60 V and current varies from 33 to 220 A. A rectifier supplies d-c for the megger test.
An outlet terminal board has connection for cables from 1.5 to 10 mm>2 and a common outlet for larger cables. All these are thermostatically controlled to prevent overheating of insulation. Meters indicate current, resistance and temperature.
For routine checking, resistances in the cold conditions are compared with the reading when a machine is heated up.
