37 3
Choose a suitable title for the text. Give reasons for your choice.
Double convertors have blocking circuits which switch the control pulses to the correct thyristors to give the required direction of the current flow. The input signal for the blocking circuits is the total current reference.
When the direction of current flow changes, the output voltage of the convertor is automatically matched to the armature voltage of the dc machine, so that current begins to flow immediately. This arrangement saves the time that would otherwise be needed to drive the current controller to the control voltage that gives through the machine.
38 6
Dwell on thyristor convertors with your fellow-student. Use ex. 36, 37.
Home exercise. Read the words, explain the function of their suffixes and prefixes. Give Russian equivalents for them:
REmove, careFULLY, installaTION, exactLY, ventilatING, openING, deterioraHON, resistANCEs, housING, insulaTION, OVERload, excess-IVE, connecTION, PREmature, rotaTION, failURE, maintenANCE, RE-newING, Disassemble, REplace, useLESS, internAL, pressURE, abra-SION, withIN, withOUT, sufficiENT, inspecTION, DEfault, REset, UNDERcurrent, UNtapped, considerABLY. machinERY, equipMENT, relationSHIP, comprehensIVE, hardWARE, reliabillTY, surveillANCE, UNused, softWARE, REbuildING, invertER, triAL, personnEL, ANTI-vibration, OVERall, Alive, ENcourage, transmisSION, Alike, domestic, throughOUT, AFOREmentioned, MISused, COUNTER-voltage.
40 20
Home exercise. Read the text and write out the names of main parts of a vacuum cleaner. Describe the steps taken by the psychiatrist in his treatment. What is your opinion of labour-saving devices?
Labour-Saving Devices
Quite a crowd had gathered in front of the local hospital. Presently the white door opened and Doctor Curewell himself appeared there. His voice sounded loud and clear when he said addressing the crowd:
— He’s gone to nuts, thinks he’s a vacuum cleaner!
— Poor old James, — murmured many voices.
You see, James Parker had a small workshop and was said to be able to mend anything from a coffee mill to a TV set. Whenever anything went wrong it was James that people went. They found him always in his workshop with a drill or a hammer in his hand, always smiling and always ready to help.
With the passage of time there were more and more various labour-saving devices, and the difficulties seemed to have piled up but this did not seem to worry old James. . . They say he loved screwdrivers and nuts as though they were living things and there was not a happier man in the whole of Suffolk. And he grew more and more famous until that dreadful day when he got it into his head he was nothing but an electrical vacuum cleaner. . . Fancy such a man wanting to suck in the dirt and dust of his house and those of his neighbours, and what a blow it must have been to all his friends!
Doctor Nut, the best psychiatrist in the country, was sent for. He came at once, examined James, and set about the work at once. The treatment was the talk of the town and the improvement came very quickly.
As soon as Mr. Parker got the electric shocks he felt he was only a part of the vacuum cleaner. Then came the cold showers which he endured bravely and after which he thought he was only tiie exhaust pipe, and gradually, as the treatment was continued (pills and injections), Mr. Parker was reduced to a switch, a plug, a piece of wire, then insulating tape and back to a man. . .
That was what Dr. Nut was waiting for. He put Mr. Parker in front of a mirror and asked:
— Who are you?
— I'm a man, — answered Mr. Parker.
— Are you quite sure you’re no longer a vacuum cleaner?
— Yes, I am,— answered Mr. Parker with determination. — I am a man
and feel strongly about it but. . . I’m not sure if my wife thinks the same! ..
Hoineiask: Ex. 39, 40.
