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J. Perelman
"Entertaining physics". Book 2.
Chapter 8. The magnetism. Electricity


In metallurgical plants you can see electromagnetic cranes, carrying huge loads. Such valves have when lifting and moving iron masses invaluable services to the steel and similar plants. Massive iron blocks or parts of machines in dozens of tons of weight with the convenience transferred these magnetic cranes without attachment. Similarly, they carry no boxes and packing of sheet iron, wire, nails, scrap metal and other materials carrying which otherwise would have required a lot of trouble.

In figures 1 and 2, you can see before me this useful service to the magnet. How busy would be to collect and transfer a bunch of iron bars, which once collected and transferred powerful magnetic crane shown in Fig. 1; here the benefit of not only saving energy, but I'm simplifying the work itself. Figure 2 you can see how the magnetic crane moves even Packed in casks nails, immediately raising six barrels! One only of the metallurgical plant four magnetic crane, each of which can carry ten rails, replace the manual labor of two hundred workers. No need to worry about applying these weights to the loading crane: while the current in the electromagnet winding, until either one shard will not fall with him.

Fig. 1. Electromagnetic crane, carrying the iron tile.

Fig. 2. Electromagnetic crane, carrying a barrel of nails.

But if the current in the winding for some reason interrupted, the accident is inevitable. Such cases were first visited. "One American plant, we read in the technical log, the electromagnet raised the iron ingots are transported in wagons, and threw them in the oven. Suddenly on the power of Niagara falls, the input current, something happened, the current was broken; the mass of metal had fallen off the electromagnet and all my weight fell on his head working. To avoid recurrence of such accidents, as well as to save the energy consumption, when the electromagnets are arranged a special fixture. After portable items raised by the magnet side down and sealed durable steel podatki, which are then themselves support the load current during transportation is interrupted".

The diameter of the electromagnets shown in Fig. 1 and 2, up to 1.5 m; each magnet capable of lifting up to 16 tons (freight car). One such magnet moves per day more than 600 tons of cargo. There are electromagnets, able to lift up to 75 tons, i.e. a locomotive!

When looking at this work of electromagnets by another reader, it may be thought, how convenient it would be to transfer using magnets red-hot iron ingots! Unfortunately, it is only possible to a certain temperature as the heated iron is not magnetized. Heated to 800°C, the magnet loses its magnetic properties.

Modern machinery Metalworking widely uses electromagnets to hold and advance steel, iron and cast iron products. Designed hundreds of different bullets, tables and other devices, greatly simplifying and accelerating the processing.

Entertaining physics J. Perelman


System Orphus


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