Magnet , around for ferrite and SmCo, about for NIB and lower for flexible ceramics, but the exact numbers depend on the grade of material. An electromagnet, in its simplest form, is a wire that has been coiled into one or more loops, known as a solenoid. When electric current flows through the wire, a magnetic field is generated. It is concentrated near (and especially inside) the coil, and its field lines are very similar to those of a magnet. The orientation of this effective magnet is determined by the right hand rule. The magnetic moment and the magnetic field of
Superconducting magnetic energy storage mean radius of coil is "R". "a" and "b" are width and depth of the conductor. "f" is called form function which is different for different shapes of coil. "ξ" (xi) and "δ" (delta) are two parameters to characterize the dimensions of the coil. We can therefore write the magnetic energy stored in such a cylindrical coil as shown below. This energy is a function of coil dimensions, number of turns and carrying current. Where Besides the properties of the wire, the configuration of the coil itself is an important issue from a mechanical engineering aspect. There are three factors