Electric locomotive DC Traction Motor

The traditional traction DC electric motor driving a train or locomotive is a simple machine. It consists of a case containing a fixed electrical part, the stator (called the stator because it is static and has the field coils) and a moving electrical part, the rotor (because it rotates) or armature as it is often called. As the rotor turns, it turns a pinion which drives a gearwheel. The gearwheel is shrunk onto the axle and thus drives the wheels.

The motion of the motor is created by the interaction of the magnetism caused by the currents flowing the stator and the rotor. This interaction causes the rotor to turn and provide the drive. The stator and the rotor of the DC motor are connected electrically. The connection consists of fixed, carbon brushes which are spring loaded so that they remain in contact with an extension of the armature called the commutator. In this way, the field coils (the stator) are kept in the circuit with the rotor (the armature and commutator).

AC and DC Motors

Both AC (Alternating Current) and DC motors have the same basic structure but there are differences. For various reasons the DC motor was originally the preferred form of motor for railway applications and most systems used it. Nowadays, modern power electronics has allowed the use of AC motors for railway applications.

Railway AC traction motor.

Vocabulary

pinion шестерня, малое зубчатое колесо пары torque вращающий момент

armature якорь gearwheel зубчатое колесо

shrink горячая запрессовка commutator коллектор

reasonably довольно, достаточно adhesion сцепление

axle ось

Task 4. Translate into Russian.

Characteristic of BLDCM

Specifications

‧Power range:250W
‧Speed range:600rpm
‧Square-wave PWM control mode, feedback signal of Hall sensor
‧Low temperature rise, high efficiency and energy saving
‧Compact size, space saving and easy installation
‧Easy maintenance, low noise and electromagnetic interference
‧Constant output torque
‧Its high efficiency is greater than the induction motor

Vocabulary

characteristic технические данные

control mode режим управления

PWM (Pulse Width Modulator) широтно-импульсный модулятор. (PWM принимает аналоговые входные сигналы и формирует два цифровых выходных сигнала, противоположных друг другу по знаку.)

feedback signal сигнал обратной связи

power range диапазон мощности

speed range диапазон числа оборотов

square wave прямоугольный импульс

maintenance содержание и техническое обслуживание

energy saving энергосберегающий

high efficiency высокоэффективный

temperature rise повышение температуры

interference ["Intq'fIərəns] помехи

PART II

SHOPPING

TEXT 1

SHOPPING

People do shopping almost every day. When people want to buy some­thing, they go to shops where various goods are sold. Through the shop-window we can see what is sold in this or that shop.Big supermarkets are self-service shop. Customers can buy all the necessary foodstuffs there: bread, milk, meat, fish, grocery, sausages, sweets, vegetables and fruit. When customers come into the shop, they take a food basket and choose the products they want to buy. When they put everything they want into the basket they come up to the cashier's desk. There is a computer with a laser scanner that reads and sums up the prices on packed goods at the cashier's desk. The saleswoman tells how much to pay. The customers pay the money and leave the shop.

At the grocer's you can buy sugar, tea, coffee, salt, pepper, ham, bacon, sausages, frankfurters and so on. Bread is sold at the baker's, meat at the butcher's. We go to the greengrocer's for vegetables and fruit. Cakes and sweets are sold at the confectioner's. When we want to buy clothes, we go to men's and ladies clothes shop. We buy boots and shoes at the footwear shop. We buy jewel­ry at the jeweler's. We buy books at the bookseller's.

Some shops may have many departments. These shops are called department stores or supermarkets. Super­markets are self-service stores with departments for dif­ferent food products. Supermarkets sell thousands of food products: meat, fresh fruits and vegetables, dairy products, canned groceries, bakery items, delicatessen items, and frozen foods. Some supermarkets also have seafood and alcohol. The supermarkets are located in shopping centres or malls and along main roads. Super­markets are popular because they save time, have low prices and variety of products in one place. There you can buy almost everything you need. These shops are called self-service shops because there are no salesper­sons there but only cashiers at the cash desks. The cus­tomers choose the goods they want to buy and pay for them at the cash desk.

СЛОВАРЬ

cannot do without не могутбез

to buy [baI] купить, покупать

various ['vFqrIqs] различный

goods товары

the grocer's бакалея

the baker's булочная

the butcher's мясной мага­зин

the greengrocer's овощной и фруктовый магазин

the confectioner's конди­терский магазин

footwear shop обувной ма­газин

the jeweler's ювелирный магазин

cashier [kx'SIq] кассир

bookseller's книжный ма­газин

salesgirl ['seIlzgq:l] продав­щица

saleswoman продавщица

salesman = shop assistant продавец

to weigh [weI] взвешивать

scales [skeIlz] весы

self-service [,self'sq:vIs] самообслуживание

mall [mO:l] ам. торговый центр

department store универмаг

canned консервированный

supermarket супермаркет, универсам

sugar [Sugq] сахар

coffee ['kOfI] кофе

frankfurter ['frANkfqtq] со­сиска

ham [hxm] ветчина

sausage ['sOsIG] колбаса

meat ['mi:t] мясо

dairy ['dFqrI] молочные продукты

bakery items ['aItqmz] хлеб­ные изделия, выпечка

Задание 10.1 Ответьте на вопросы.

1. What are shops for?

2. Where do people go when they want to buy some­thing?

3. What can see through the shop-window?

4. What can we buy at the grocer's?

5. What can we buy at the baker's?

6. What can we buy at the greengrocer's?

7. What can we buy at the butcher's?

8. What can we buy at the confectioner's?

9. What can we buy at the footwear shop?

10. What can we buy at the bookseller's?

11. Where do the customers pay for the goods at the self-service shops?

12. What is a supermarket?

Text 2

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