English
中文简体There are several factors and considerations that go into design and the Considerations for Magnet Selection, some of which are Magnets Strength, Magnet Coercivity, application, Size and Shape, last but not the least the Cost of the magnet.
Magnet Strength
The strength of a magnet can be found in the magnet specification known as BHmax, which is the maximum energy density of a magnet. This is defined in Mega Gauss Oersteds, or MGOe. On a Magnetic Demagnetization Curve this is the highest point of the magnet’s strength, or the magnet’s maximum energy product.
Magnet Coercivity
In the world of permanent magnets, there are a couple of ways manufacturers or suppliers define the coercive force, but we will concentrate on the most widely used, which is the lettering system. This letter system uses the following letters after the grade to define the magnets specification to fight demagnetization forces: M, H, SH, UH, EH, and TH.
Size & Shape of Magnet
Size & Shape of the magnet also plays its part. For example, a very thin N45H may be listed as able to handle an operating temperature of 120C, however, if the size of the magnet is extremely thin, or the shape is very tiny, it may be better to choose an N45SH material.
Cost
The reserves of permanent magnet are mostly dominated by China and due to its nearabout 45% share of the whole worlds reserves, the cost is bound to be high.
Conclusion
There is no doubt that Permanent magnets prove to be a better alternative, for EV, in terms of efficiency but their production effects,cost, and vulnarability for high operating temperature pose a mojor threat. The non-permanet magnets e.g. Induction motors may be a better alternative considering the sustainability factor which is important for our future generations.
