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US 4,734,632 AGranted
Driving device for a stepping motor
AssigneeSilver Seiko Ltd.
InventorsShigeo Kamikura, Yasushi Ema
Life of this patent
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AssigneeSilver Seiko Ltd.
InventorsShigeo Kamikura, Yasushi Ema
Estimating the term…
A driving device for a stepping motor wherein detection of a position of the rotor of a stepping motor can be effected accurately without the necessity of adjustments of various elements. The device detects a current flow in a field winding of an energized phase and compares it with a simulated saturation curve to detect a back EMF induced in the winding to find a current position of the rotor of the motor. The simulated saturation curve is produced by energizing the winding with a low voltage, measuring current flows in the winding as voltage signals at three different points of time, and calculating several data indicating a saturation curve from the voltage signals. The data are stored in memory and recalled one after another to produce a corresponding voltage when the field winding is energized.
A driving device for a stepping motor, comprising:
A simulating device for producing a simulated saturation curve for a field winding of a stepping motor, comprising means for detecting a current flow in the field winding as a voltage signal, means for energizing the field winding with a first predetermined voltage insufficient for the motor to rotate, means for taking voltage signals from said means for detecting at different points of time before and after starting energization of the field winding, means for calculating several values of said saturation curve from the voltage signals at the different points of time, means for storing the calculated values therein, means for successively recalling the stored values when the field winding is energized with a second predetermined voltage to rotate the motor, and means responsive to each of the recalled values for producing a voltage corresponding to the values.
Dependencies are inferred from the claim text.