Switched Reluctance Drives Limited

Emerson Electric Company

James Christopher Smart

David Mark Sugden

Peter Richard Mayes

Joseph Gerald Marcinkiewicz

Phillip G Langhorst

A rotor position transducer for an electronically commutated electric motor has a vane mounted to rotate with the rotor and a pair of sensors, according to one embodiment. One sensor has an output coincident with positions of zero torque. The other sensor produces signals slightly in advance. Overlapping portions of the signals denote regions of different levels of torque. The second sensor output can also be used in high-speed, single-pulse control of the motor. Method embodiments and other apparatus embodiments are also disclosed.

Starting of single-phase motors

A digital power factor correction circuit including a digital comparator that compares the actual DC bus voltage of an electric circuit with a desired DC bus voltage to produce a digital attenuation signal in the form of a pulse width modulated signal that is used to attenuate the voltage from a time-varying source. The attenuated source voltage is used as the current demand signal for a current controller that controls the current drawn from the line.

Digital power factor correction circuit

A single-phase variable reluctance motor is disclosed. The motor includes a stator having a pair of projecting poles defining a principal axis and a rotor mounted on a rotatable shaft co-axial with the principal axis of the stator. The stator may have inwardly extending poles that terminate in a central bore and the rotor may be rotatably disposed in the central bore. In such an embodiment, the stator poles are arranged generally diametrically opposed to one another. The rotor is mounted on a shaft and has a pair of poles generally diametrically opposed from each other. The stator and rotor may be formed from laminations of a ferromagnetic material. Energizing coils are wound around one or more of the stator poles. When energized, the energizing coil(s) impart a torque on the rotor causing it to rotate. One or more permanent magnets are inserted into the winding(s) forming the energizing coil(s) to park the rotor in a preferred starting position when the motor is turned off. A pair of slot wedges is also provided to separate the energizing coils from the central bore. The slot wedges are inserted into notches formed in the stator poles to retain the slot wedges in the central bore. The slot wedges have cut-out portions which are aligned with the permanent magnets to expose them to the central bore.

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Horsforth, United Kingdom

James Christopher Smart