Established in 1992, China Qiangjin Power Co., Ltd. is a professional switched reluctance motor manufacturer and dealer of in the emergency power supply industry. We not only specialize in manufacturing different kinds of generators, but also in motors, engines, diesels, gearmotors and other power supply products. Now, our OEM switched reluctance motors products are exported to North America, Europe(UK, France, Germany, Italy), USA, Japan and Canda. Our company has obtained the certifications of ISO9001-2000, GS/TUV, CE, VL, EPA, QHS, SON, CAP and SRS.

A switched-reluctance cryogenic motor (ref. 1) is being developed for pollution-free flight, which is one of NASA’s goals for the 21st century. Before a super-high-power-density motor can be developed for the next-generation all-electric propulsion system, a noncontact rotor-bearing system is necessary to circumvent the poor bearing life that ordinarily accompanies cryogenic operation.
Recently, a variety of bearingless motors--including permanent magnet, induction, and reluctance--were introduced. These motors have different characteristics and different suitable applications. Among them, switched-reluctance motors can be good candidates for the electric propulsion system because they have inherent fault-tolerance and rotor robustness at high rotational speeds (no coil windings on the rotor). In addition, this type of motor generates a high radial force in the air gap that we might be able to use for rotor levitation (bearing function).

This motor does not have separate magnetic bearing coils, but only motor coils, as in a conventional motor configuration. The motor coil windings on the stator generate a radial force (bearing function) and torque (motor function) at the same time. On a stator with superimposed differential magnetic bearing coil windings on the motor coil windings, the radial force is a function of the radial force winding current and the motor current, as well as of the rotor rotational position.
We used the fringing effects based on the Maxwell FEM model shown in the preceding illustration to derive the relationships between the radial force and current around unaligned positions. The radial equations developed using Takemoto’s method and Shuang’s method are compared with three-dimensional FEM results in the following graph.