November 16th, 2018
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Electromagnets – How Do They Work?
If you don’t work with electromagnets yourself, or thing the closest you’ve ever got to one was your high school physics class, then think again, because they’re all around us in our everyday lives.
What is an Electromagnet?
Speaking very basically, an electromagnet is a magnet created by the flow of an electrical current due to Ampere’s Law, which you can read about here. The simplest electromagnets – you can even make them yourself – consist of a wire wrapped around a magnetic core made of ferromagnetic or ferrimagnetic core, such as iron.
A (Very) Brief History of the Electromagnet
The relationship between electricity and magnetism was first thoroughly investigated in 1873, when the Scottish physicist, James Clerk Maxwell, noticed the interaction of negative and positive electrical charges, including polarity, and magnets’ ability to repel and attract. After this discovery, the power of electromagnets has been harnessed, and the humble magnet still has a place in the appliances we use today.
Household Appliances that Use Electromagnets:
- Microwave ovens
- Record Players
This is by no means an exhaustive list – countless appliances and machines we use every day work on the principles of electromagnetics in certain parts of their structure. In fact, almost anything that uses electricity to function uses magnets.
Electrical and electronic equipment coupled with an electromagnetic environment created electromagnetic compatibility, or EMC. There is a lot of science behind how equipment, like the above, has to have its magnetic emissions controlled and tested. Places like MCS Test Equipment are dedicated to providing the equipment to do so. But where else can we find electromagnets outside of the domestic environment? Read on to find out.
In today’s society, we’re waking up to the fact that we need to move away from traditional fossil fuels to reduce out negative impact on our global environment, that’s why electric cars are growing in popularity. Electric car motors use electromagnets to work. Strong magnets that encircle a spinning wire coil that emits a magnetic field. This magnetic field opposes that of the magnets, causing the coil to rotate at high speed. The force of the magnetic repulsion is used to control the energy source, making the motor run, and giving us a car that doesn’t need your standard combustion engine.
Perhaps the most exciting technology that magnets are responsible for is the maglev train, a portmanteau of ‘magnetic’ and ‘levitation.’ These trains basically hover above their tracks due to the principle of electromagnetic suspension. Both repulsive and attractive magnetic forces are used in the track to create this effect.
Because of the fact that maglev trains levitate above the ground and harness magnetic force, they both run very smoothly and very fast. The trains do have to have wheels though; at slow speeds and in stationery positions, the magnetic flux is not enough to hold up the train.
The joys of electromagnetism don’t stop there. The principle of electromagnetism makes it so versatile that a comprehensive list of their uses would probably take up and entire book. We have a lot to be thankful of electromagnetism for.