Design of a high power density, permanent magnet, axial gap DC motor

The design of a drive motor for undersea vehicles is described. The basic motor consists of two discs containing permanent magnets on each side of a magnetic structure containing the copper windings. Copper cooling may easily be accomplished through the use of liquid circulating through the stator windings. The role of field and armature in a conventional disc motor configuration are reversed. The two discs containing the permanent magnets are rotating. The brushes are on the discs. The magnetic structure with the coils is stationary. The commutator bars are imbedded in the stationary member. Input power is supplied to the brushes through a brush-and-slip ring assembly. An electromagnetic design analysis for a 92-ft-lb, 700-r/min motor was performed. A finite-element analysis has been conducted, and the results show that magnetic saturation is not a limiting factor in this design. The motor torque is achievable within weights and volume constraints