10-04-2017, 09:22 PM
Permanent-magnet-less machine having an enclosed air gap
A synchronous system generates high power density at a high torque to weight ratio. some of these brushless slip-ring-less constructions have a reduced size, lower weights when without permanent magnets. A permanent magnet-less, brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by an alternating current.A rotor disposed within the magnetic rotating field is placed away from the stator to form an air gap relative to an axis of rotation. The radial air gap and the stationary excitation core spaced apart from the rotor encloses the stationary excitation core. stator core gaps are included by some permanent magnet-less, brushless synchronous systems to reduce axial flux flow. The quadrature-axis inductance may be increased in some synchronous systems.
The high power density and driving torque of these systems may be used in other applications that have short, intermediate, or long core lengths. the excitation fields may be cut off to enhance safety, fields may be boosted to increase or reach peak acceleration power in short time periods .The systems may be operated as an alternating current machine, a motor, and/or a generator.
for more details and the drawings, visit:
http://freshpatents-dt20090903ptan20090218895.php?type=description