Step motor exciting apparatus
US4490664A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 20, 1982 |
| Grant date | Dec 25, 1984 |
| Priority date | — |
| Expiry date | Oct 20, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus for exciting a step motor such as a step motor employed as a drive source for conveying original documents in a reading device such as a facsimile system. To vary the feed pitch in the auxiliary scanning direction of the original, staircase waveform exciting currents are applied through A-phase and B-phase exciting coils of the step motor. The apparatus of the invention provides for equal step sizes of the two waveforms and waveforms which are precise complements of one another. Currents flowing in the two exciting coils are sensed and voltages representing the sensed currents are divided in ratios determined by division ratio control signals read from a ROM. The divided signals are compared with a reference signal to provide pulse drive signals of constant currents during each step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.