The Use of Permanent Magnets in Electric Motors
Motors are all around us! They are practically indispensable in almost every major industry and can be found wherever there is mechanical movement. In the average household, you will likely find electric motors in your washing machine, microwave, refrigerator, ceiling fans, hairdryers, electric razors, and the list goes on. On an even smaller scale, micro-motors can be found in your most-used electronics — computers, laptops, and cellphones.
Motors use the power of magnetism to create rotational motion. Think about attracting and repelling forces and how they cause movement. Building a simple motor requires the following parts: rotor, commutator, brushes, axel, field magnet, and a power supply.
Most important are the two magnets, the first being the rotor, which is an electromagnet. The second is the field or permanent magnet. Technically, you can use two electromagnets, but using a permanent magnet saves power, especially in smaller motors.
What Type of Magnet Should You Use?
When it comes to a field magnet, you can choose between several types — samarium cobalt, neodymium, or ceramic magnets. Each has its benefits, depending on your specific application. Rare earth magnets (samarium cobalt and neodymium) are generally up to three times stronger than ceramics, but they are also more expensive. There is also the ever-present matter of corrosion and temperature to contend with.
Samarium Cobalt and Neodymium
While both types of rare earth magnets are extremely strong, samarium cobalt is more resistant to high temperatures and corrosion. For this reason, they typically withstand high-temperature motor applications better than neodymium.
Neodymium magnets are more vulnerable to corrosion, however, this can be combated by adding a protective coating such as nickel or copper-nickel plating. Despite neodymium’s shortcomings in relation to temperature, it produces the most energy. When deciding which type to use, consider both maximum temperature required and total cost.
Ceramic magnets are much less powerful than rare earth magnets, but also less expensive. In addition, they exhibit stubborn resistance to demagnetization and corrosion. The maximum operating temperature for ceramics is 482°F, but any losses can be recovered once the operating temperature is reduced. Extremely cold temperatures, however, can lead to a permanent loss of strength.
Use Apex Magnets Today
If you are interested in any of the above-mentioned magnets — samarium cobalt, neodymium, or ceramic — please explore our website. Whether you are building your own motor or trying to implement magnets into the process of your unique industry, we can help you select the type, size, and shape that best fits your application.