Direct axis aiding permanent magnets for a laminated synchronous motor rotor

A rotor for a permanent magnet synchronous motor having a stator developing a rotating direct axis flux comprising, in combination,

• a shaft journalled about an axis,
• magnetically permeable inner and outer portions of said rotor defining a plurality of magnet apertures,
• a plurality of magnets in said magnet apertures,
• said inner portion lying between said magnets and said shaft and said outer portion lying between said magnets and the outer periphery of said rotor,
• said magnets being magnetized to establish an even plurality of magnetic poles on the periphery of said rotor by the flux of said magnets and with the flux of said magnets being additive to the direct axis flux of the stator at no load,
• said magnet apertures being elongated and considerably more narrow in a dimension along a rotor radius than the dimension parallel to a tangent to the shaft,
• said magnet apertures being positioned relatively closely to said shaft to establish said outer portion of said rotor with a larger radial dimension than that of said inner portion,
• said outer portion forming a large volume relative to said inner portion for a large pole shoe on each pole to carry the flux of said magnets,
• and said pole shoe having a wide arc in the order of 160 electrical degrees.