Alex Slocum of MIT has some great design tool spreadsheets.
- Energy in a magnetic field, Ramo et. al.:
- For linear materials, where
- Force per unit area (pressure) is
- In the case of free space (air), :
@ B = 1 Tesla
@ B = 2 Tesla
- In a closed magnetic circuit:
To build a strong electromagnet, a short geometry, with large area is preferred. Note that most Ferromagnetic materials saturate around 1-2 Tesla. This occurs at a field intensity of:
For this reason, there is no point in building an electromagnet with a higher field intensity.