What are rare earth magnets?

We’ve been busy putting together the latest issue of our company newsletter Driving Forward, and in one article on SynRM electric motor technology we mentioned rare earth magnets. Once the piece was written we decided that we should explain a bit more about rare earth magnets and their use in electric motors. The result is this blog – we hope you find it as interesting as we did!

The chemistry

Rare earth magnets are the strongest permanent magnets made. They’re made from alloys of the so-called ‘rare earth’ metals, which are classed as a specific group of 17 chemical elements. However, these elements are actually quite plentiful, so why are they referred to as ‘rare’?

Well, due to their geochemical properties, rare earth elements are normally dispersed and not typically found concentrated as rare earth minerals in ore deposits. The scarcity of these minerals (previously known as ‘earths’) resulted in the term ‘rare earth’.

The reason for using rare earth elements in magnets is that they are ferromagnetic, meaning they can be permanently magnetised. This is especially useful for electric motor production.

Use of rare-earth magnets in electric motors

Rare earth magnets were developed in the 1970s and ‘80s and until recently have been ideal for electric motors because they can produce far stronger magnetic fields than ferrite or alnico magnets, leading to excellent performance.

However, rare earth magnets are very expensive meaning motors containing them aren’t economically viable for some users.  Therefore, advanced technology such as SynRM is welcomed as it means more economical magnets can be used without compromising the motor’s performance.

Gibbons have four decades’ experience building and supplying electric motors, so if you have any questions you’d like us to answer or would like a competitive quote then call 01621 868138 or email info@gibbonsgroup.co.uk and benefit from our expertise.