EM may be ac & dc devices according to the current used. They may have the form of simple solenoids, plunger EM, EM with external armature, & lifting magnets which are usually circular in form with a flat holding surface.
A single straightway magnet illustrated in Fig.9 is a solenoid provided with a movable rod/armature/ called a plunger. When the coil is energized by the command from the transducer, the iron becomes magnetized due to magnetic flux closing through a core 2 & the plunger. The mutual action of the magnetic field in the solenoid on the poles created on the plunger causes the plunger to-move within the solenoid. This force becomes zero only when the magnetic centers of the plunger & solenoid coincide. If the load is attached to the plunger, work will be done until the force to be overcome is equal to the force that the solenoid exerts on the plunger. The force F increases as the plunger pulls into the solenoid, i.e. as the distance decreases. The maximum uniform pull occurs whCn the end of the plunger is at the center of the solenoid. It'iS twice the initial force when the plunger is at the end of the stroke. Whema stronger pull is desired, a stop may be used. Such tractive magnets are usually two & three-phas£ devices, the last capable of developing a greater pull. Straightway magnets in applications other than the solenoid-operated valve are more compact & fast in action.
48. / 15 мин./ Прочтите текст и запомните его содержание. Завершите приводимую ниже схему, отражающую последовательность операций при замене подшипника.
Change of Bearings
The complete type designation of bearings /clearance, series number etc./ are marked on the rating plate of each machine. It is important, when ordering a new bearing, the type is given in full.
When the machine is opened for changing of a damaged bearing, or for some other reason, the old grease must be removed from the inner cover of the bearing housing e.g. by using white spirit. The cover is fitted back to its place on the shaft before mounting the bearing.
The used bearing shall be washed clean, immediately after which it is lubricated as a safeguard against rust. A new bearing in its original packing must not be washed.
For mounting, the bearing is first heated up to 80...90 C. The definite lubrication for running is done first after the bearing is
Flow Chart
| 1 | . 2 | 3 | 13 |
| give in full the type designation | | | | | | |
mounted & cooled. Before mounting the bearing, check that -the fitting surface on the shaft & end shield is not damaged. The bearing is mounted on the shaft always so that the side with the markings of the manufacturer on it is outwards. Before mounting the machine, remove the old grease & clean also the other bearing & lubrication parts. Special care must be taken that no foreign bodies, e.g. metal particles, are left in these parts. ^
49. /ТО мин./ Прочтите диалог и скажите, какиеТгзменения произойдут в технике и в природе человека через 200*лет.
In 200 Years
Mrs Mix: The supper will be served in ten minufes. Where’s Frank?
Professor Mix: It won’t be long before he comes, dear.
Mrs Mix: Not on the moon again, I hope?
Prof ./frightened/: Yes, darling! On the moon. I’ve sent him there to get me stones, but there's nothing to worry about. He’ll be given a lift here. By the time you make tea the spacecraft will have Been broughj down to the garden.
Mrs Mix: & what about Dorothy?
Prof.: She’ll be sailed in one or two seconds.
Mrs Mix: Where from?
Prof.: From Japan, dearest! It’s all my fault. I asked her to hand in my scientific report. You see, the conference begins at 8 o’clock in the morning...
Mrs Mix/angrily/: & where’ Bob?
Prof.: Oh, he’s in the yard playing with the atomic bombs. They will have been defused by now, I suppose. Mrs Mix/furiously/: Now, you’re the limit. How can you let him do that? Don’t you know it’s cold today? Remember, if he has temperature, I’m not to be blamed for it.
Ключи.
6 - adijkno
7 - bcdfgijlmnpqtvxa’
8 - dfhik
9-1,3, 4, 6, 7
11 - сущ. - acfhjlmoqv, прилаг. - bdgkstw
