International Business Machines Corporation

Hi Dong Chai

Joseph P Pawletko

A high performance, low cost variable reluctance stepper motor has an integral structure with a ring and a plurality of aligned salient pole members. A plurality of teeth are located on the face of each pole member. Windings are disposed on alternate ones of the pole members and a high impedance means isolates the pole members from one another. A rotor with a plurality of teeth and a plurality of holes disposed thereon coacts with the pole members and is moved in a step fashion by the sequential energization of the windings. The flux generated by the energization of the windings is confined to a short path and coupling to the remainder of the structure is negligible. Recesses positioned symmetrically around the structure also serve to enhance flux splitting and reduce adjacent flux coupling.

Low inertia high torque variable reluctance motor

A serial line printer uses a linear stepper motor of the variable reluctance type in which the toothed stator bar acts as a guide and support for the print mechanism carrier. Sensor elements movable with the carrier sense the presence of the teeth of the stator bar and generate timing signals usable for controlling operation of the printer and the motion of the carrier. The pitch of the teeth in the stator bar is proportional to the spacing of the print locations in a line of print.

Serial printer with linear motor drive

A three phase rotary stepper motor of the variable reluctance type comprises a rotor and an annular stator having three pairs of diametrically opposed stator poles wound with bifilar windings. The stator windings are connected so that opposed poles are energized as a pair having the same polarity. The bifilar winding is connected so that pole pairs are energized with either polarity. A two phase energization scheme is used which causes adjacent poles of two pole pairs to have opposite polarity, while the third pole pair is magnetically neutral. Every three steps of the sequence the magnetically neutral pole pair is magnetized with the reverse polarity.

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Hi Dong Chai