How Do Air Gaps Affect Magnets?
When it comes to considering factors that can reduce the performance of a magnet it is important to consider air gaps, any non-magnetic material that prevents magnetism from attracting to another magnet or ferrous object.
Air gaps can be formed if the contact steel is rusty, dirty, painted, or uneven, and these will all cause a loss of magnetism. The bigger the air gap, the bigger the reduction in the magnet’s performance and pull.
Air gaps affect the magnetic circuit that a magnet produces, breaking these circuits and subsequently forcing the magnetism to ‘jump’ from the magnet to the other object to continue the circuit.
How Does Air Gap Affect Magnet Selection?
If there is a potential or certain air gap in your application, it’s important to select a magnet with greater strength in order to compensate for the magnetic strength being lost as a result of the air gap.
For example, by mounting a magnetic hook to a wall in an office or home, the magnetic field must travel through numerous non-magnetic materials in order to reach the stud within the wall it is attracting to. This application has a large air gap present.
Whereas if you were to hang a magnetic hook directly to a ferrous surface in a warehouse or garage, there will not be very much of an air gap present at all, aside from the actual air. Meaning you can use a magnet with less strength.
If an air gap is not taken into consideration when choosing a magnet for your application, you may not be able to select the correct magnet for your application.
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