Abstract:
A method of controlling a two-phase stepping motor to operate in one of a plurality of operating modes in which output of the motor behaves differently upon encountering obstacle, comprises the steps of: generating an electrical driving current comprising a repeating series of a positive active driving region, a first inactive driving region, a negative active driving region and a second inactive driving region; determining one of the duration of the active driving regions and the duration of the inactive driving regions relative to the other of the durations to thereby cause the motor to operate in a corresponding mode of the operating modes; and applying the driving current to the motor.
Abstract:
An indicator of a meter is driven by a step motor in which a rotating magnetic field formed by field coils which is a composite of magnetic fields of the coils supplied with a sine-wave-driving current and cosine-wave driving current. The indicator is also returned to a stopper located at a zero position of the meter by the rotating magnetic field. A part of the rotating magnetic field, which is formed from the sine and cosine waves in a range of the phase angle between -340 degree and -(180 degree-.DELTA.a degree) in the zero-return process, is cut after the indicator rests on the stopper so that such part of the rotating magnetic field may not separate the indicator from the stopper.
Abstract:
A pulse motor driving apparatus for the optical unit in a copying machine includes an excitation phase designating circuit for designating phase windings alternately from one phase to two phases and from two phases to one phase at the time of original scanning or forward rotation, and also designating the phase windings in pairs with every two phases at the time of return of the optical unit or reverse rotation. A drive circuit supplies drive pulses successively to the phase windings designated by the excitation phase designating circuit to rotate a pulse motor faster at the time of reverse rotation than at the time of forward rotation.
Abstract:
A stepping motor exciting system in which the excitation current is set at one of four stepwise values. When the motor is to be driven in a stepwise manner, the excitation current is in the form of a pseudo-trapezoidal wave which is derived in terms of two of possible four values. When the motor is to be driven in a linear manner, the excitation current is in the form of a pseudo-sinusoidal wave which is derived in terms of all four possible values. A ROM stores these sequences of excitation currents and controls the exciting system in accordance with the driving mode desired.
Abstract:
A stepping motor control circuit permitting selective operation of the motor in various modes such as half or full step mode. The circuit includes a pulse generator producing pulses at a selected motor step rate. A switch means selects the step size while a second switch selects the motor direction. An up/down counter counts pulses from the pulse generator in a direction correlated with the selected rotation direction. A read-only-memory is addressed as a function of the periodically repeating count in the up/down counter and the selected step size. The stored information at the addressed read-only-memory location actuates motor drive circuitry which generates energizing signals for the motor windings to drive the motor in the selected direction a distance corresponding to the selected step size at a step rate equal to the pulse rate of the pulse generator.
Abstract:
The stepping motor is wound with five star-connected field windings. Drive for five-phase operation is generated with logic circuitry having provision for forward and reverse. Increased torque as compared with a conventional three-phase system, and equal torque per step are achieved.
Abstract:
A method of controlling a two-phase stepping motor to operate in one of a plurality of operating modes in which output of the motor behaves differently upon encountering obstacle, comprises the steps of: generating an electrical driving current comprising a repeating series of a positive active driving region, a first inactive driving region, a negative active driving region and a second inactive driving region; determining one of the duration of the active driving regions and the duration of the inactive driving regions relative to the other of the durations to thereby cause the motor to operate in a corresponding mode of the operating modes; and applying the driving current to the motor.
Abstract:
A reference signal generation unit generates a reference signal VCA showing a current limit value with a staircase waveform. A PWM control unit compares a measurement signal SENA obtained by a coil current measurement unit with the reference signal VCA at intervals of a PWM timing signal generated by a PWM timing signal generation unit, and switches transistors of a bridge rectification circuit ON and OFF according to the comparison, thereby PWM controlling a supply current to a coil. A discharge instruction signal generation unit issues a discharge instruction signal MMCPA when the reference signal VCA decreases. In response, a PWM control unit forms a current path in the bridge rectification circuit to cause a regenerative current to flow back into a power supply and capacitor.