The innovative and unique features – most notably the conical mating of the rotor and stator and the axial flow of the flux path – implemented in the NovaTorque motor design result in a dramatically more efficient and cost-effective device.
Click the graphic below to view a video of the motor construction of NovaTorque’s patented Generation 1.0 PremiumPlus+™ motors. NovaTorque has since introduced its Generation 2.0 design, with very significant further improvements in efficiency, performance, and power density. But, the basic design concepts (conical air gap, axial flux path, bobbin wound windings, etc.) are the same. Watch for a new video of the new design coming soon.
The field poles used in the stator produce conical end-surfaces, instead of the conventional perpendicular flat cross-section. The rotor hubs have mating conical shapes that match the end-surfaces of the field poles. This approach maximizes the surface area available for magnetic flux transmission, while minimizing the volume of materials. In fact, the rotor/stator surface area interface is twice the perpendicular cross-sectional area of the stator field pole. The increased surface area at the rotor/stator interface concentrates the magnetic flux density. This allows NovaTorque to use lower cost ferrite magnets to achieve motor efficiency and performance that equals or exceeds much more expensive motors that use rare-earth (neodymium) magnets.
Another relatively unique feature of the NovaTorque design is its axial flux path. The NovaTorque motor flux flows straight (parallel to the shaft) through the axially-oriented field poles of the stator. Grain-oriented transformer grade steel can be used in this orientation, which lowers eddy current losses and results in improved efficiency.
The axial orientation of the stator field poles also allows the use of bobbin-wound coils. This type of coil is easier to wind and requires less conductor material than the coils that are wound in the slots of a typical, radially-oriented motor. This coil arrangement also creates a better thermal path, because one face of the coils is next to the external motor case, instead of being inside the lamination stack as is found in an induction motor.
The rotor in the NovaTorque motor design consists of a pair of hubs mounted on opposite ends of the motor shaft. The rotor hubs use an interior permanent magnet (IPM) arrangement which provides another source of flux concentration. A further benefit of an IPM design, due to its saliency, is better sensorless motor control.
Regal Beloit America, Inc.
531 N. Fourth St.
Tipp City, OH 45371