and torque may arise even in the two dimensional case. 2. Deﬁning the magnetostatic problem The problem of ﬁnding the magnetic vector potential and the magnetic ﬂux density for a Halbach cylinder is deﬁned in terms of the magnetic vector potential equation through the relation between the magnetic ﬂux density, B, and the The magnetic moment of a magnet is a quantity that determines the force that the magnet can exert on electric currents and the torque that a magnetic field will exert on it. A loop of electric current, a bar magnet, an electron, a molecule, and a planet all have magnetic moments.
Electrical motor torque is proportional to the product of magnetic flux and the armature current. Mechanical or load torque is proportional to the product of force and distance. Motor current varies in relation to the amount of load torque applied.