5. The suspenders can be lowered either by unwinding the cable from the drum manually or by means of an electric drive.
6. The principle mode of operation of a boat winch drive consists of lifting the boat, once at a time, a limited time period not longer than 5 min. The boat lifting speed is 0.1 to 0.15 m/s. The choice of the motor must be made so as to ensure starting of the motor at the maximum design load. As the boat lifting time must not exceed 5 min the motors may have to sustain heavy overloads as compared with the catalogue data which represent 60 min ratings.
7. The control systems for the motors of the boat winches are quite simple. Starting and stopping of a-c motors are effected by means of magnetic starters with a local push button control which may be reversible or non-reversible, depending on the construction of the winches. Hometask: Ex. 35, 36.
6 —beghkln; 7 — cdfghiklnoqtuwxy W c' d'; 8 — abeghikln;
9 — 2, 3, 5; 10 — 9. Нужно считать, что эти данные являются в значительной степени приближенными. 10. Действительно, оказалось, что дело обстоит именно так. 11. Полагали, что эти реакции не протекают бурно. 12. Этот метод, дающий, как ранее указывалось, хорошие результаты, теперь широко
применяется. 11—efjop; 12—1 cdfkm, 2 abgijl; 13 — 2. Он находится в безвыходном положении и не видит выхода.
3. Сухое дерево легко загорается. 4. Клин клином вышибают. 5. Вряд ли кто-нибудь захочет подвергнуться новому обстрелу со стороны печати. 6. Если вы упустите эту возможность, она вам больше не представится. 7. Ну, начинай (выкладывай)! Что заставило тебя это сделать? 8. Многие рабочие этой фирмы были уволены и увеличили армию безработных. 19 — 4. Помимо общего знакомства с принципом работы и устройством отдельных элементов и приборов в целом, необходимо тщательно изучить расположение отдельных частей в приборе. 20 — Sources of electric power; 27—lb,
2c, 3a, 4d, 5f, 6h, 7e, 8g; 33 — a) 1,5, 6; b) 2, 7, 8; c) 3, 4, 8, 9.
SECTION 4 (4 + 2 + 5)
Ordering Directions and Standard Equipment
The first class period
Review of “AVR”, “Electric Drive of Boat Winches”, “Built-in Brakes”.
15
Topical content: Ordering directions and standard equipment.
Grammar item: Subjunctive Mood. 10
Ordering Directions and Standard Equipment
1. For ordering electric drive equipment for ship’s deck machinery consult tables listing electric drives of various applications.
2. After determining the power rating of servo motors from the formula given in the catalogue select a power drive equipment with the nearest power rating and then make sure tiiat the control properties of the drive indicated on the mechanical characteristics suit the operating conditions of the electric equipment set.
3. The order for delivery of an electric equipment set or a separate motor must contain the following information:
name of the machinery (gear), kind of the current and the ship’s mains voltage;
type of the motor and its electrical characteristics as indicated in tables;
provision of a built-in disk brake and the operating conditions of the brake;
design version of the motor;
number of the free ends of the shaft (without a built-in brake); set number according to tables;
number and type of limit switches in the standard equipment; provision of a spares set;
provision of a Certificate issued by the USSR Register.
4. For ordering separate electrical apparatuses use the data given in tables.
5. The order for delivery of a magnetic controller and a cam controller must contain the following information:
application of the magnetic and cam controllers; class protection; rated current; number of startings per hour; type; operating duty; electric wear ' resistance level; control circuit voltage; voltage; settings of thermal protection relays.
6. An example of an order for an electric equipment set:
Electric equipment set for a mooring capstan, 380 V A. C. Motor MA 11 421-4/8 A, two-speed, power rating 7.0/5 6 kW, rotation speed 1400/650 rpm, 30/30 min duty.
Built-in brake type TNT 42, braking torque 12 daNm, 60 min duty. Design version-vertically mounted, flange type, without feet, M 302, for building into capstan head.
