Foundation, Concrete and Earthquake Engineering

What Are Magnetic Bearings?

Bearings are used to create frictionless movement between two parts. There is a wide variety of bearings including ball bearings, needle bearings, thrust bearings and even magnetic bearings. What is a magnetic bearing? Well as the name suggests it is a bearing that supports its load using magnetic forces rather than using mechanical contact. Usually in a bearing the bearing touches the two parts and the load is moved along, with a magnetic bearing they don't even have to touch, it is all done by magnetic force. This means the bearing can levitate and rotate its load without wear and friction which is impossible to avoid with non-magnetic bearings as it needs physical contact.

What uses are there for magnetic bearings?

The great thing about magnetic bearings is that there is no contact and so no friction and so no need for lubrication and they can operate in a vacuum. For these reasons magnetic bearings are used in a lot of machines with pumps and motors and generators. A common machine that you will know is your electric meter reading machine. Magnetic bearings are used within these machines to help read the power of a buildings electrical consumption. Other industrial appliances you will expect to find them are electric power generation, petroleum refining, machine tool operation and natural gas pipelines.

What are the advantages of using magnetic bearings?

The main advantage to magnetic bearings which we have already mentioned is the no-contact aspect and so no need for lubrication. But what does this really mean, why is it so advantageous? Elimination of the lubrication in certain machines means the elimination of the lubrication system as well. For example with oil lubricated bearings there is no need for the whole oil lubrication system for the pumps, valves, coolers, ducting and so and so on. Every part in a machine is at risk of failing and so removing a system or part of it with the machine still being able to work removes one of the risks, plus it saves the manufacturer money from having to build and install this section.

A lot of machines need to operate at high temperatures, now the bearing is fine to cope with these temperatures but the lubricant is often not and sets on fire or fails in other ways when it reaches a certain temperature point. By not needing a lubricant a magnetic bearing can be used in these high temperature machines with no problems. 

There are many advantages to using magnetic bearings, these are just a few but many more exist, such as better vibrational control, improved reliability of the bearing and fewer failures, longer life of the bearing as there is no wear and tear and so on.

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