FAQ - Frequently Asked Questions
What do the specifications N40, N42, N45, etc. mean?
The numbers (e.g., 40, 42, 45) are equivalent to approximately the maximum energy product of the magnet (in MGOe).
The letters N, M, H, SH, UH or EH say something about the maximum working temperature, which can be 80, 100, 120, 150, 180 or 200 °C. Most of our magnets begin with an "N" and should be used at 80 °C. You can find more detailed information under our FAQ What temperatures can magnets sustain?.
When we speak colloquially about the "power" of a magnet, we usually mean either the adhesive force on direct contact with a metal plate or the attractive force to a piece of iron (or another magnet) at a certain distance.
The power is not only determined by the magnetic material used; equally important are the following factors:
- Volume of the magnet
- Form of the magnet
- Proportions of the magnet (e.g. the ratio of the diameter to the height of a disc magnet)
- Combination with other materials, e.g. is the magnet mounted on a piece of metal, in a metal pot, or is it "free-standing".
This is similarly true in relationship to the working temperature. The specified maximum temperature can only be used without a problem when the aspect ratio of the magnet is "ideal". If a magnet is, for example, very thin in relation to its diameter (or side length), the maximum temperature is reached earlier.
If you take any two magnets of different sizes and magnetisation from our collection, the difference in their strength is more due to the differences in their volume than the differences in their magnetisation. That's why the larger magnet is mostly the stronger magnet, even when its magnetisation classification is somewhat smaller.
You can find the exact associations between these classifications and the physical values of a magnet in the table Physical magnet data.