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Question: What are some of the main every day uses for electromagnets.



Answer: Electro-magnets always have a soft iron core which increases the strength of the magnet. The core has to be soft - this means magnetically soft- so that when the current is turned off the magnetism disappears with it.

There are hundreds of different kinds of jobs that are done by using electro-magnets. Here are some other uses:

You can slide the bolts of locks and latches, tap out telegraphic dots and dashes, open and close switches in distant electric circuits. The rotors of all electric motors are spun by electro-magnetism.

A relay is a device which uses a low current circuit to switch high current circuit on/off. A large relay system is used in cars for switching the starter motor, because it draws a very big current.

When the switch in the low current is closed it turns the electro magnet on, this attracts the iron rocker. The rocker pivots and closes the contacts in the high current circuit. When the low current switch is opened the electro-magnet stops pulling, the rocker returns and the high current circuit is broken again.

Electro-magnets have been used in hospitals to remove particles of metal ( those which are magnetic- because not all common metals are magnetic, e.g. aluminium, copper, brass, gold, silver), which may have lodged in people's eyes after an accident.

Some large cranes in scrapyards are electromagnetic. The electro-magnet is made up of a big coil of wire, with many turns and a soft iron core.

The crane lifts large pieces of metal when the current is switched on and drops its load when the current is switched off.

A circuit breaker, also called a resettable fuse is electro-magnetic. This is placed on the incoming live wire. If the current gets too high the magnetic field in the coil pulls the iron rocker which "trips" the switch and breaks the circuit. It can be reset manually but will always switch itself off if the current is too high.





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