Abstract: A static frequency changer for feeding a synchronous machine and composed of a mains side static converter, a machine side static converter and a direct current intermediate circuit connected between the converters, is further provided with an additional static converter connected at the machine side in parallel opposition to the machine side static converter, and a direct voltage capacitor connected in parallel to the additional converter.

Abstract: Graphics and text data are combined selectively to discharge incremental areas of a charged electrophotographic member to form thereon a latent text and/or graphics image represented by the graphics and text data, the imaged member thereafter being toned and output from the system so that the toned image may be fused on the member and the member may be used as a printing plate in an offset lithographic printing press. The apparatus includes an optical system that may form a maximum of 22 individual rays which are deflected twice through a field flattening lens and then onto the charged member. The optical system further includes an optical scale or grating which provides electrical signals indicating the precise location of the individual rays along scan lines on the member. The apparatus further includes an electronic system which generates electrical signals from the graphics and text data to form the 22 individual rays.

Abstract: A frequency detector produces a pulse train from an emf generated across a three-phase induction motor in the decelerating mode with its pulse repetition frequency proportional to the speed of the motor. A phase locked loop synchronizes this frequency with that of a variable frequency oscillator for a variable frequency inverter and the synchronization is maintained by the phase locked loop and a ramp generator controlled with the signal from the detector. When the detected frequency equals a command frequency from a reference circuit, the inverter starts to operate the motor. When the start operation has been completed, the phase locked loop is disabled while the ramp generator is connected to the reference circuit to change the frequency of the inverter to the command frequency to complete the restart operation of the motor.

Abstract: A power factor type motor controller in which the conventional power factor constant voltage command signal is replaced during a starting interval with a graduated control voltage. The present invention adds to the three-phase system of pending application Ser. No. 199,765, filed Oct. 23, 1980, means for modifying the operation of the system for a motor start-up interval of 5 to 30 seconds. The modification is that of providing via ramp generator 174 an initial ramp-like signal which replaces a constant power factor signal supplied by potentiometer 70. The ramp-like signal is applied to terminal 40 where it is summed with an operating power factor signal from phase detectors 32, 34, and 36 to thereby obtain a control signal for ultimately controlling SCR devices 12, 14, and 16 to effect a gradual turn-on of motor 10.

Abstract: An accelerator control for field-controlled DC motors, or other applications requiring non-linear response to linear control input. The control uses a photodetector detecting light reflecting from a movable vane connected to the control input.

Abstract: Disclosed is an apparatus for controlling the rotational speed of an electric motor based upon the load encountered by the electric motor. A load sensor provides a voltage level based upon the operating load of the electric motor and accumulates this voltage in accordance with the cycle of the alternating current supplied to the motor. If during a cycle of the alternating current, the voltage exceeds a predetermined level, a transistor will be biassed into conduction, said transistor turning off a thyristor and preventing any further conduction of the thyristor during that cycle of the alternating current. Thus the duty cycle of the thyristor determines the total amount of current supplied to the electric motor and this current level determines the rotational rpm of the motor.

Abstract: A first static commutator including a first controllable thyristor rectifier and a first thyristor inverter and a second static commutator including a second controllable thyristor rectifier and a second thyristor inverter are provided. First three-phase AC voltage is supplied to the first controllable rectifier, and second three-phase AC voltage 30 degrees out of phase with said first three-phase AC voltage is supplied to the second controllable rectifier. A brushless motor includes first star-connected three-phase windings receiving the output of the first inverter and second star-connected three-phase windings and 30 degrees out of phase with said first three phase windings. During the starting period of the brushless motor the conduction of the first and second satic commutators is switched for every 30-degree rotation of the brushless motor.

Abstract: A method of operating a laundry machine. The machine has a pair of rotatable components and is driven by an electronically commutated motor having a stationary assembly with a plurality of winding stages and also having a rotatable assembly adapted to be selectively coupled to at least one of the rotatable components. In this method, a DC voltage for application to the motor is received, and a first control function is imposed on the operation of the machine to control the application of the DC voltage in accordance with a selected one of a plurality of first waveshapes so as to provide a resultant effective voltage to the motor.

Abstract: A digital speed control system for a sewing machine comprises a digital speed setting device which responds to manual depression of a foot pedal by generating a digital position signal. A variable frequency divider divides the frequency of speed related pulses so that its output frequency is an integral submultiple of the input frequency, which is variable as a function of the digital position signal. A period detector senses the interval between pulses that occur successively at the output of the frequency divider and generates binary data representing the sensed interval. The interval representing data are translated into second period data in an arithmetic unit according to a predetermined transfer function. A pulse generator translates the second period data into a pulse for activating a magnetic clutch or a magnetic brake depending on the sign of the second period data to accelerate or decelerate the sewing machine.

Abstract: A feature of this invention is the provision of a reversible, D.C. shunt field motor having an armature and two separate field windings, each field winding being capable of producing rated field flux. The motor is capable of bidirectional rotation having one field energizable for CW rotation and the other field energizable for CCW rotation. A servo system couples the two field windings and has only one active control element in the high current armature circuit to control the magnitude of the armature current, and two low power amplifiers, each low power amplifier having an active control element and each controlling the magnitude of the field flux (and thereby the magnitude of armature current under certain circumstances) in a given respective direction.

Abstract: Apparatus for maintaining a constant linear velocity for a PCM disc record which includes a detector for optically detecting the PCM signal on the record and supplies the output to a differentiating circuit and a rectifier circuit with the output of the rectifier circuit supplied to a peak detector circuit which supplies its output to a level comparator that also receives a reference level from a reference source. A first phase comparator also receives the output of the rectifier circuit and controls a voltage controlled oscillator through a low pass filter and the output of the voltage controlled oscillator is supplied to the phase comparator. A divider receives the output of the voltage controlled oscillator and supplies a first input to a phase comparator which also receives an input from a reference frequency generator. The outputs of the level comparator and the phase comparator are supplied to the motor drive circuit which controls the drive motor for the disc record.

Abstract: A control device for multispeed motor having a first circuit for providing a detection signal whose period corresponds to a rotation speed of the motor, a trigger pulse generator connected to the first circuit for generating a trigger pulse corresponding to the detection signal, and a second circuit connected between the trigger pulse generator and the motor for providing a drive signal in accordance with the trigger pulse. The motor, first circuit, trigger pulse generator and second circuit form a closed negative feedback loop.

Abstract: A sewing machine drive having a mains rectifier (1) which, via a chopper (2) operating at a relatively high frequency, supplies direct current pulses to the driving motor (3). The duty ratio of these driving pulses is controlled as a function of a nominal value transmitter (11) and a current limiting circuit (14) controlled by the motor speed. This produces a smooth quiet, vibration-free operation of the motor (3) or the driven machine with a high degree of motor efficiency. Moreover, a speed-dependent current limitation occurs in such a manner that at high speeds a limited maximum current flows, which at the same time results in an output limitation.

Abstract: A starting control circuit is provided for an alternating current motor having a run winding and a start winding and a mechanical rotational output. The motor is powered by an alternating current source. A reference oscillator produces pulses having a reference frequency. A first control circuit is provided for counting the number of reference pulses produced during a predetermined number of cycles of the alternating current source. A sensor is provided for sensing a predetermined amount of rotational movement of the mechanical rotational output of the motor and producing a sensor pulse indicative thereof. A second control circuit is provided for counting the number of reference pulses produced during the time between a predetermined number of sensor pulses and for comparing the counts on the first and second control circuits. The second control circuit assumes first and second output states dependent on the relationship between the first and second output counts.

Abstract: A motor control is provided for a DC series motor operative with a chopper apparatus and including a thyristor switch to determine the field shunt operation of the motor. A voltage reversal that occurs across the field windings when the chopper is OFF and not conducting is utilized to commutate and enable modulation of the field shunt thyristor switch as desired in relation to the chopper ON and OFF operation.

Abstract: A light pipe information display, having a non-conductive, transparent planar first glass sheet and a non-conductive planar opaque second glass sheet, both sheets being disposed adjacent to one another with their inner surfaces opposing one another in spaced-apart relationship. The second non-conductive sheet has a plurality of discrete transparent light pipes formed therethrough, wherein at least one of said non-conductive sheets includes electrical conductors disposed on its inner surface. The conductors are connected to an electrically responsive display material, such as a liquid crystal or electroluminescent material disposed between the first and second sheets, arranged in discrete character-forming segments. Each segment is aligned with one of said discrete light pipes. There is a third opaque sheet disposed on the exposed surface of the second sheet and includes a plurality of smaller light pipe holes, each hole being aligned with each light pipe window of the second sheet.

Abstract: Improved operation of a pulse width modulated inverter machine drive system is obtained by a control apparatus which regulates inverter switching device conduction by modifying switching signal waveforms transmitted to the inverter to eliminate switching pulses narrower than the minimum inverter switching device pulse width. By dropping the narrow inverter switching pulses in sequence during the exact interval which the pulses would otherwise occur and boosting the amplitude of remaining pulses, the control apparatus permits the inverter to smoothly transition from pulse width modulation operation to square wave operation without objectionable jumps in inverter output voltage.

Abstract: To form an irregularity-free thin layer of developer on a developer supporting member, the surface of the developer supporting member is formed with concavo-convexities along the conveyance direction thereof. To eliminate any irregularity of the developer layer on the developer supporting member and to sufficiently impart charge to the developer by the friction between the developer and the supporting member, the concavo-convexities should preferably have a pitch of 5-100.mu., a concavity depth d of 0.2-10.mu. and a concavity width W of 2d-3d. The concavo-convexities should desirably be rounded rather than sharp.

Abstract: A digital speed control system for a sewing machine comprises a digital speed setting device which responds to manual depression of a foot pedal by generating a digital position signal. A variable frequency divider divides the frequency of speed related pulses so that its output frequency is an integral submultiple of the input frequency, which is variable as a function of the digital position signal. A period detector senses the interval between pulses that occur successively at the output of the frequency divider and generates binary data representing the sensed interval. The interval-representing data is translated into a second period data in an arithmetic unit according to a predetermined transfer function.

Abstract: A windshield wiper device for automobiles including a control circuit for controlling a wiper drive motor. The control circuit has a wiper switch including an intermittent position wherein the wiper is intermittently driven. In the intermittent position of the wiper switch, the wiper is at first driven for one complete stroke. Then, after a desired time, the operator actuates a time interval setting switch whereby the wiper is thereafter driven intermittently with the desired time interval.