Electricity: motive power systems – Open-loop stepping motor control systems
Patent
1983-03-29
1984-10-30
Dobeck, B.
Electricity: motive power systems
Open-loop stepping motor control systems
318685, H02K 2904
Patent
active
044802188
ABSTRACT:
By choosing the winding and drive circuit configuration of a conventional two phase step motor so that during any one step time, a drive current pulse in one winding is not magnetically coupled to the other winding, then the back EMF induced in this other winding by the permanent magnet of the motor can be used to generate a feedback emitter pulse. The zero crossings of the induced EMF coincides with the detent positions in a conventional two phase step motor. Only one winding of the two phase step motor is driven during any step time. In order to use this same winding as an emitter signal source during the next step time, the drive current in this winding is reduced to zero before the zero crossing of the EMF waveform which is induced in this winding by the permanent magnet of the motor. The drive current is quickly reduced by using a supply voltage substantially higher than the rated motor voltage.
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B. C. Kuo and K. Butts, Closed-Loop Control of a 3.6.degree. Floppy-Disk Drive PM Motor by Back-EMF Sensing, NSF under Grant No. ECS 79-10829.
T. Higuchi, Closed Loop Control of PM Step Motors by Sensing Back EMF.
Bergmann Saul M.
Dobeck B.
Hesse Karl O.
International Business Machines - Corporation
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