Abstract: A method and apparatus for controlling a multiple motor drive arranged to drive printing cylinders of a printing machine sychronously decelerates each of the drives upon a failure or defect occurring in one or more of the components of the drive system such that the individual printing cylinders are decelerated in a manner synchronized with one another with respect to rotation angle. The apparatus includes a main control device which detects a failure in one of the drive system components and controls the drive units to decelerate the drive units to a standstill in accordance with a time function. The time function is determined by the rotation of the drive unit which contains the component that failed.

Abstract: The invention concerns a method and an apparatus for actuating a plurality of synchronous motors which are connected to a common power supply and which are respectively used for displacing an element between two limit positions and have a connection Y1 for forward motion, a connection Y2 for reverse motion and a neutral connection G. In that case the respective connection between the connection Y1 or Y2 which is in use and the power supply is interrupted by means of a limit switch which responds when the element reaches a limit position. The connection between the connection Y2 or Y1 which is not in use and the power supply remains interrupted during non-use. A respective switch element having a control input is connected upstream of the connection Y1 for forward motion and the connection for reverse motion. The control input of the switch element is connected to a respective control circuit which includes the respective limit switch.

Abstract: An electric vehicle control device for a plurality of vehicles connected in series to form a formation including a plurality of control devices, each being provided for one of the vehicles, respectively. Each of the control devices includes a PWM converter device for receiving a first A.C. power through a current collector and a transformer from an A.C. overhead line and for converting the first A.C. power into a D.C. power using a PWM carrier wave, an inverter connected to D.C. output terminals of the PWM converter device for converting the D.C. power into a second A.C. power, and an electric motor connected to A.C. output terminals of the inverter for being driven by the second A.C. power. Phase angles of the PWM carrier waves in the PWM converter devices are determined to be mutually shifted by a predetermined angle, thereby higher harmonics of the PWM carrier waves leaking into the A.C. overhead line are reduced.

Abstract: A weaving machine having a rotating main shaft for driving the weaving machine, with a plurality of accessories on the weaving machine for weaving cloth is provided with an artificial signal of shaft position. A generator generates the artificial signal representing the desired angular position of the main driving shaft of the weaving machine. This generator generates the signal independent of actual angular position of the main shaft. A drive drives the main shaft of the weaving machine. The drive is responsive to the signal for the desired angular position of the main shaft. This drive responds independently of the actual angular position of the main shaft of the weaving machine. At least one weaving machine accessory is present for performing functions on the cloth being woven, such as a thread tensioning device, cloth takeoff device, or nozzle controls, for projectile-type weft insertion. These accessories also receive the artificial signal of desired shaft position, and function responsive to the signal.

Abstract: A Direct Current drive system with a multiplicity of applications including that of powering electric vehicles. The system contains a hybrid electric motor formed by a unique synchronous arrangement of two electrical motors, a primary and a secondary. The single input of Direct Current to the primary motor enables the secondary motor to operate on the Alternating Current generated in the primary motor, and in doing so captures the transformation of energy that takes place during the collapse of a magnetic field. This captured energy is then used to help drive the secondary motor, thus greatly increasing efficiency. A brake/alternator is included to provide a means of slowing/ stopping the motor while at the same time assisting in recharging the primary power source by sending current through a rectifier to the battery which powers the motor.

Abstract: The rotor spinning machine includes a plurality of asynchronous motors for driving the operating elements of the machine. The motors run up from a standstill condition to an operating speed under the initial mass load of the operating elements. The machine includes a single soft-start control apparatus control circuit configured with the motors and the soft-start control apparatus for individually and successively connecting the motors to the soft-start control apparatus in a predetermined hierarchy.

Abstract: Two windshield wiper blades are powered by separate electric motors. The blades overlap and when one blade is at its reversal point the other blade leaves part as the other blade begins to return to park. The position of the blades is encoded. The blades, if synchronized should be at identical locations and position codes at the same time. Motor power to the blade that arrives first is be removed, allowing the blade to coast. If the other blade still does not arrive at the position after an elapsed time, the first to arrive blade is dynamically braked. Intermittent wiper operation is provided in a way that initiates an immediate wipe if wiper delay is changed while the blades are parked.

Abstract: At least two commutator type motors are arranged to reduce cyclic voltage imbalances or oscillations by connecting a check diode in series with the armature of each motor, and by partially interlocking the motors by connecting the series winding of a neighboring motor to the end of the armature which is not connected to the check diode.

Abstract: A system for synchronizing a plurality of motors is disclosed. The system includes a universal drive controller which can control the operation of two motors, a power module for each motor, and a power module interface rack which is utilized to interconnect the motor to its associated universal drive controller. If a plurality of universal drive controllers is involved, a common clock is utilized to synchronize the operation of same.Synchronization of the motors is achieved by monitoring the output shaft of each motor through the use of a resolver, transmitting feedback data relative to the position of the output shaft to the universal drive controller via the power module interface rack, calculation of command data by the universal drive controller to effect synchronization, and transmitting the command data to the power module interface rack wherein the power module causes the proper firing signals to be transmitted to the associated motor.

Abstract: A system and method for initializing a plurality of mechanical elements of a machine includes a plurality of housings and an uncoordinated motion controller. The housings are coupled to the mechanical elements and include at least a motor controller electrically connected to a motor. Each of the motor controllers have an associated position sensing component for sensing the position of the associated mechanical element along one axis. The uncoordinated motion controller instructs the motor controllers to operate its associated motor until the associated mechanical element reaches an initialization position. The velocity and acceleration profile of the respective motors are independent of each other, such that each of the motors moves its associated mechanical element in uncoordinated motion until each mechanical element reaches its initialization position. A multi-node daisy chained data bus electrically connects the uncoordinated motion controlling means and the motor controllers in series.

Abstract: A system, which may be a cooling system for a motor vehicle engine, has two direct current motors together with switching circuits which provide selective connection of the windings of the two motors to a direct current voltage source in such a way as to obtain different operating modes for each motor. One of the motors has four brushes, the first of which is permanently connected to the first polarity of the source, while its second, third and fourth brushes are arranged so that they can be connected to the appropriate source polarities respectively through either three interruptors or two. The second motor has two brushes permanently connected, respectively, to the same first source polarity and to the third or fourth brush of the first motor.

Abstract: An AC variable speed driving apparatus including an AC motor and an inverter for driving the motor. The AC motor includes a synchronous motor and an induction motor. The synchronous motor includes first stator windings and a first rotor having a permanent magnet. The induction motor includes second stator windings and a second rotor. The first and second stator windings are disposed so that they do not magnetically interfere with each other. The first and second rotors are mounted on a common axis of rotation. The inverter supplies AC power to the stator windings so that the synchronous motor and the induction motor are driven independently. A highly efficient, large output and low cost system can be realized in a wide speed range.

Abstract: A communication system comprising a master station and a plurality of slave stations connected for serial transmission by a transmission line, using a HDLC-type protocal. Each of the slave stations is equipped with a system counter and a control timing setting register. Each slave station receives data when address information included in a transmission frame sent by the master station matches its own address and presets the system counter so that control timing for the object to be controlled by the master station matches the timing by the one or more slave stations. As a result, plural slave stations can output a control signal which matches the control timing for an object to be controlled by master station when the contents of the system counter match the contents of control timing setting register. The predetermined value may be preset and may be based on a collection of actual control timing data between the master station and each slave station.

Abstract: An inverter controlled conveying/measuring apparatus according to the invention includes a conveyor (3) for conveying an object (W) of measurement. The conveyor (3) is driven by an AC motor (M2). Inverter (20) controls and operates the conveyor (3) at a given speed by supplying the AC motor (M2) with frequency converting signals according to a specified frequency. A measuring section (4) is arranged on a conveying path of the conveyor (3) in order to measure an attribute of the object (W) being conveyed by the conveyor (3).

Abstract: A ball screw apparatus having a revolving position detector for detecting revolutions of a ball screw nut and a ball spline nut and a number-of-revolutions altering means for issuing a command to decrement or increment the number of revolutions of the ball screw nut so that a difference between sets of revolution numbers becomes zero. In the ball screw apparatus, a driving motor is disposed in parallel with a driving shaft. An output of the driving motor is transmitted via a belt to each nut. When driving the motor in a clutch-off/brake-on state, only the ball screw nut is driven to revolve, and the driving shaft is slid in the axial direction. When driving the motor in a clutch-on/brake-off state, the two nuts revolve together, and the driving shaft is rotationally driven. A reduction ratio on the side of the ball screw nut is set equal to that on the side of the ball spline nut, whereby the two nuts synchronously revolve.

Abstract: A warp knitting machine comprises a brake operative upon current interruption. The guide bars are displaced by an electrical setting motor as well as a control arrangement, which establishes the position of the guide bars in dependence upon the angular position of the main shaft. The control arrangement bases its control upon a predetermined displacement function relating the positions of the main shaft and guide bar. The setting motor and control arrangement are connected to a main power source via an intermediate circuit, which has at least one storage condenser. This machine allows for a rather rapid change of the lapping pattern and a continuance of controlled guide bar displacement right up to the standstill of the main shaft.

Abstract: A control arrangement for displacing the guide bar in a warp knitting machines comprises an input arrangement for the setting certain characteristic data defining the desired shogging pattern. There is also provided a first storage section for storing data for various transition curves also relating to shogging patterns. A computer can generate a continuous displacement function based on the characteristic data and the transition curves. An output arrangement can reads out the values of the displacement function in dependence upon the rotation angle position of the main shaft 7 of the knitting machine. The values this read out are used as position target values for the guide bar. This enables flexible adaptation to produce very different patterns in high machine speed.

Abstract: A warp knitting machine comprises at least one guide bar and one main shaft. The angular position of the main shaft is determined by an absolute transmitter, while the position of the guide bar is determined by an absolute transmitter. Each transmitter can provide a different signal value for each angular position of the main shaft and for each guide bar position. A continuous displacement function is developed for the guide bar. This function relates each measured angular position of the main shaft with a position target value for the guide bar. A position control circuit controls a setting motor that displaces the guide bar. In this way, the danger of collision between elements of the guide bars and other working parts of the machine are practically totally avoided.

Abstract: A wiper apparatus for wiping the windshield of a vehicle with a plurality of wiper blades operated by a plurality of wiper motors which comprises an intermittent switch, autostop switches disposed to the respective wiper motors, relays for operating the respective wiper motors in response to ON-states of the respective autostop switches, a relay driving circuit for driving the relays, a first timer circuit responsive to OFF-states of both the autostop switches for generating a first timer signal, a second timer circuit responsive to an intermittent signal from the intermittent switch and the ending edge of the first timer signal for generating a second timer signal, a third timer circuit responsive to an ON-state of either autostop switch for generating a third timer signal and holding the relay driving circuit to drive the relays, and a prohibiting circuit for forbidding and permitting the operation of the relay driving circuit according to the first timer signal and the second timer signal, respectively.

Abstract: A multiplexor circuit connects a plurality of stepper motors to a lesser number of stepper motor drivers with at least one driver connected to a plurality of parallel connected stepper motors. A control computer through a multi-axis position controller generates step commands to the drivers to move one or more stepper motors a predetermined amount, at a predetermined speed and in a predetermined direction of rotation. The computer configures switches in the multiplexor circuit to connect selected ones of the stepper motors to selected drivers such that a plurality of stepper motors may be connected in parallel to a single driver such that a single driver can sequentially drive multiple stepper motors thereby reducing the number of drivers required for a plurality of stepper motors.

Abstract: A method of controlling a stepping motor for supplying a drive current to each of the phase windings thereof in response to control signals. The control signals are formed by combining logically phase exciting signals and overdrive signals in synchronization with a clock pulse signal. Each of the overdrive signals also includes a pulse with a longer width at an earlier stage of a phase exciting duration during which a drive current flows in the stepping motor and a pulse with a shorter width at a later stage of the phase exciting duration. Hence, a small drive current flows in the phase windings after a later stage of the exciting duration, thus reducing power consumption.

Abstract: A windshield wiper system has two motors. Each propels its own wiper blade. A blade parking disk is attached to each motor and contains a conductive and a non-conductive segment. Electrical power supplied through the conductive segment to the motor from a "parking contact", is interrupted by the non-conductive segment, parking the blade. During normal operation, the voltage change on the "parking contact" is sensed for each motor to determine if one motor is faster than the other. If the speed difference exceeds a set level, power to the faster motor is interrupted for a preset time interval during each rotation of the parking disk, until the difference is less than the set level. The voltage on the parking contact is also sensed for the higher voltage produced if the motors are operating at high speed. If the motors are operating at high speed, the preset time interval is increased and the allowable speed difference is reduced.

Abstract: There are provided servo motors and servo control units for n shafts. A setting device previously sets parameters for servo control individually for each of the n shafts and previously sets parameters for servo control for a synchronizing operation. Data which determines synchronization conditions of servo motors of respective shafts is applied, when required, by an input device independently of setting by the setting device. The data which determines the synchronization conditions includes, for example, data of combination of synchronized shafts and data of section for synchronization. A moving pattern preparation device determines servo motor shafts to be synchronously controlled on the basis of the synchronization condition determining data applied through the input device and prepares a moving pattern to a target position on the basis of the parameters for servo control set by the setting device with respect to each servo motor shaft to be synchronously controlled.

Abstract: The present invention relates to a motor control device using an inverter or inverters, in particular, it relates to a motor control device suitable for the prevention of inertial rotation of a motor or motors or for the maintenance of synchronized operation of a plurality of motors in a service-interruption time; a DC side voltage is compared with a target voltage and a correction signal relating to the deviation voltage is added to a speed instruction for the inverter; thereby in a service-interruption time a motor can be continuously and smoothly decelerated keeping the DC side voltage of an inverter at a target voltage value. By utilizing a motor control device according to the present invention for a spinning machine etc., unevenness in thread winding or thread cut in a service interruption time can be prevented.

Abstract: Windshield wiper systems are commonly used on vehicles that must operate out-of-doors. In systems employing two or more wiper elements, each operating from an individual wiper motor, some mechanism must be employed to prevent out-of-sync operation from causing the wiper elements to collide if they operate in an overlap area. The instant wiper system includes first and second electric motors each drivingly connected to a respective windshield wiper element. Switching devices selectively controllably provide electrical power to the motors in response to receiving respective motor control signals. Synchronizing devices provide first and second synchronizing signals in response to the respective wiper elements being positioned at corresponding predetermined cycle start locations. A logic circuit controllably produces the motor control signals in response to receiving the respective synchronizing signals.

Abstract: A ring spinning machine with various driving systems 10, 12 for driving spindles, driving arrangements, ring rails and the like is regulated in the case of power failure down to a zero revolution range while maintaining preselected revolution relationships. The driving system which is allocated to the load with the greatest effective inertia serves, at first, for the supply of the other driving system in a generator service. Only in a lower revolution range are the driving systems backed via a battery of relatively low capacity.

Abstract: In a machine tool having first and second spindles, which are connected to respective spindle motors and control circuits each control circuit including a velocity controller and a position controller, and which simultaneously grasp the same workpiece, in which state the workpiece is subjected to machining. At such time, a digital velocity command provided by, e.g., a numerical control unit, is supplied to the two spindles simultaneously, switches for isolating the position controller from the velocity controller at each spindle is controlled at the respective spindle, a synchronous operation mode, which changes over the velocity command to a position command, is established, and the digital velocity command value is processed as a position command, whereby the two spindles are subjected to identical positional control. As a result, the rpm's of the spindles are synchronized and the workpiece can be machined and separated into two parts without subjecting it to excessive force.

Abstract: The drive system connects a servomotor via a clutch to a shaft after the motor has started up from a standstill to a speed in synchronism with the supply frequency to the servomotor. The clutch may also be actuated to disengage the servomotor from the shaft when the servomotor is slowed to a predetermined speed during stopping of the servomotor. A transmission is employed between the servomotor and the shaft to compensate for any shocks to the motor when engaging the clutch.

Abstract: A synchronous control system for a pair of spindles of a machine tool including a master spindle and a slave spindle. Current positions of the main spindles are detected, and a deviation between the detected current positions is calculated. In case the deviation is within 180 degrees, the current position of one of the main spindles which precedes in the forward direction of rotation is determined as a target position for positioning. In case the deviation is greater than 180 degrees, the detected current position of the master spindle or the slave spindle is offset by an amount equal to an integral number of times 180 degrees so that the deviation between current positions of the main spindles after such offset is within 180 degrees. Then, that one of the current position of the main spindle thus offset and the current position of the other main spindle not offset which precedes in the forward direction of rotation is determined as a common target position for positioning.

Abstract: In a control system for synchronous rotation of the cutter heads in a multi-cutter shield machine, the rotation cutter heads are so disposed in generally the same plane such that the distance between the centers of the adjoining cutter heads is larger than the radius, and smaller than the diameter, of the cutter heads. The rotating cutter heads are driven independently of each other by electric drive systems, respectively. Each of the electric drive systems consists of plural motors with a reduction gear, coupled to the respective rotating cutter heads by means of a pinion and gear. The motor rotation is so controlled and the cutter heads are so synchronously rotated, that the angle of deviation between the cutter heads is within such an allowable range that the cutter heads will not interfere with each other even if there is any imbalance in excavating and rotating resistances between the cutter heads.

Abstract: An electric driving device for openable members in which an openable member is opened and closed by rotation of driving shafts provided on right and left sides. The device includes a motor which rotates the driving shafts via a reduction mechanism, and switching relays which switch the rotational direction of the motor. Open and close command switches command the opening and closing of the openable member and a rotation synchronization sensor associated with the motor generates pulses synchronized with the rotation of the motor. A mechanical stopper limits the rotation of the driving shaft which is rotated via the reduction mechanism of the motor and a motor lock detecting means detects locking of the motor by detecting the pulse width generated by the rotation synchronization sensor. Also, an actuation stopping arrangement stops the actuation of an actuation device which supplies current to the motor if a signal is generated by the detection apparatus that detects locking of the motor.

Abstract: A safety device for use in a recording apparatus controls the on/off operation and prevents the malfunction of motors for driving a gear flange to rotate a light sensitive drum and for driving an actuating gear and other driving members in accordance with a signal indicative of the reference rotational frequency received from an oscillator and a signal indicative of the rotational frequency of each motor. A motor control circuit is used including motor drivers for controlling the operation of said motors and a fault detection circuit for detecting the malfunction of said motors by comparing an adder output indicative of said motors' rotational frequencies with threshold values in a comparator, thereby ascertaining the long-term use of the light sensitive drum.

Abstract: A numerically-controlled electromechanical precision drive system in which a plurality of low-current servomotor units are arranged in a circle around the driven shaft or push rod of an intermediate gear-wheel in such a way that pinion gears linked with its driven shaft engage with the intermediate gearwheel. The motor units are each driven in synchronism and are each independently linked with an emergency power supply and drive electronic system which receives the control pulses from a joint electronic control system, thus producing a multi-torque drive which provides the operating shaft with a rotational and/or translatory movement.

Abstract: A lapping machine for correcting the asymmetrical hardening distortions which occur during the hardening of gear wheels, especially bevel gears, is disclosed. This machine is particularly advantageous in connection with large bevel gear transmissions or drives produced in small batches. This is achieved by selective lapping, in that both bevel gears are each driven by a respective separate speed-regulated electric motor. An electronic transmission or drive, also referred to as an electric shaft, controls and regulates one electric motor to serve as the master motor and the other to serve as the slave motor as a function of the rotational speed of the master motor and the gear ratio of the two bevel gears. A device serves for controlling and regulating a selectable relative lapping torque.

Abstract: The apparatus positively induces synchronism in at least two lifting jacks. It has an upwardly and downwardly movable carriage, on the lifting jack, a column, a lifting device extending along the column, a first control device to control the lifting device in the "lift" direction, a second control device to control the lifting device in the "lower" direction, a "lift" switch on the main lifting jack, a "lower" switch on the main lifting jack. For each lifting jack, a motor device acts on the lifting device. Along each column there is an equally spaced marking unit, the spacing corresponding to the maximum admissible lift difference between the lifting jacks. Each marking unit has an `ON` zone and an `OFF` zone. Rigidly fixed to each carriage is a tracer for scanning the marker units. Each tracer, is in an electrical switching device, and inhibits the motor device when the tracer is in the `OFF` zone, until such time as the tracer of the carriage which is lagging most behind is also in the `OFF` zone.

Abstract: A tool spindle is driven by a motor and is connected to an angle of rotation transmitter. The signal of the transmitter connected to the tool spindle represents the desired value for the drive of a work piece spindle. The angle of rotation of the workpiece spindle is measured with another transmitter. A control deviation signal which is fed into a servo amplifier of the workpiece spindle drive via a controller is formed from both transmitter signals. A variable observer circuit into which the control deviation signal is also fed is arranged in parallel to the controller. The control deviation signal is stored sequentially in several sample and hold circuits by means of a multiplexer circuit during one tool revolution. The content of each sample and hold circuit is integrated by means of a respective integrator. During the following cycle, a correction signal, which is added to the output signal of the controller, is formed by sequential interrogation of the integrators by means of a demultiplexer circuit.

Abstract: A control for an electrically powered, motor vehicle windshield wiper system with independent drive motors for the wiper blades which produces an opposing wiper pattern with overlapping park and which is simple and inexpensive to manufacture by providing a unique switching system which coordinates the blades to prevent interference therebetween and converts simply and effectively, when the system is turned off, to a blade parking control which allows continuation of normal blade movement into a predetermined park position. The control provides switch control for the motor of each wiper blade in response to certain predetermined positions of the other blade, including, in particular, a position adjacent but outside the wipe pattern of the other blade wherein the controlled blade may be stopped if necessary to avoid interference.

Abstract: The apparatus positively induces synchronism in at least two lifting jacks. It has an upwardly and downwardly movable carriage on the lifting jack, a column, a lifting device extending along the column, a first control device to control the lifting device in the "lift" direction, a second control device to control the lifting device in the "lower" direction, a "lift" switch on the main lifting jack, a "lower" switch on the main lifting jack. For each lifting jack, a motor device acts on the lifting device. Along each column there is an equally spaced marking unit, the spacing corresponding to the maximum admissible lift difference between the lifting jacks. Each marking unit has an `ON` zone and an `OFF` zone. Rigidly fixed to each carriage is a tracer for scanning the marker units. Each tracer, is in an electrical switching device, and inhibits the motor device when the tracer is in the `OFF` zone, until such time as the tracer of the carriage which is lagging most behind is also in the `OFF` zone.

Abstract: An emergency battery power supply for a ring-spinning or ring-twisting frame can be brought into operation by an automatic circuit to bridge brief power failures and effect programmed shutdown of the motors upon longer power failures, with the speed ratios between the motors being maintained substantially to standstill to avoid yarn breakage during shutdown.

Abstract: The invention relates to a control device for synchronizing a plurality of driving units, the speed thereof controlled by a time-variable desired signal which is common for all units. For each driving unit a positional control means in combination with a speed control means is provided. The positional control means receives a signal for the desired position of the correlated driving unit which signal is produced in an integrating means from the desired speed signal and further receives a signal representing the actual position of the unit. The output signal of the speed control means is added to the desired speed signal modified in an amplifying network. The gain control of the amplifying network is selected such that the transient response of the compensating means is inversely proportional to the transient response of the actuating means and the drive unit. This allows for a high synchronizing accuracy.

Abstract: An electric drive includes two d.c. electric motors electrically connected therebetween, each of them comprising a stationary former of magnetic field, a movable portion 1,2, an excitation winding 3,4, and an armature winding 5. A commutating device 25 is connected to the armature winding 5. The former of magnetic field is a ferromagnetic strip 22 or 23 provided with pole-forming projections disposed in two rows in the chessboard order. The armature winding 5 is common for both the motors, its sections being uniformly distributed among the motors, and the ends of the sections are led out at the side of one of the motors and connected to the commutating device 25 for forced commutation of the sections in a function of a relative location of the ferromagnetic modules of the movable portions and pole-forming projections.

Abstract: A reel-to-reel constant speed tape transducer in which the torques of the reel motors are controlled to maintain the tension in the tape to the take-up reel substantially equal to or slightly greater than the tension in the tape from the supply reel. The speed of the take-up reel provides a measure of reel diameter to generate signals which control the torque of the reel motors.

Abstract: A plurality of AC synchronous motors used to drive respective machines in a manufacturing or packaging assembly line or system are driven in speed and phase synchronization. A common AC current supply signal is inverted to provide one polyphase set of series of controlled frequency low voltage DC pulses in a lead inverter. This polyphase set of pulses are amplified and utilized to drive the AC synchronous motor for the lead machine in the system. This same set of polyphase pulses are also transmitted directly to follower inverters respectively and there amplified to drive respective synchronous motors in the system to not only insure speed synchronization but also absolute phase synchronization in driving all machines in the line. When the frequency of the polyphase set of pulses is varied to correspondingly drive the AC synchronous motors at predetermined speeds, phase synchronization of the motors will always be insured.

Abstract: An apparatus for changing the relative angles of the output shafts of a multiple-motor electric drive. For this purpose, the appropriate synchronous motor is switched to a phase-shifting frequency changer and its relative shaft (mechanical phase) angle is shifted by varying the frequency. The synchronous motor is then switched back to the operating frequency changer. The phase equality of the output voltages of the two frequency changers is monitored by signals derived from logic elements driving the frequency changers. In normal operation, the phase shifting frequency changer is driven by the same digital frequency generator as the operating frequency changer and is only switched to another frequency generator for phase shifting. Transition from one frequency changer to the other is made without shock.

Abstract: A system for determining the relative angular positions of two magnetic-p rotors of respective synchronously driven (same speed) synchronous motors operated from a common frequency generator applying the driving frequency to the motors. Each rotor is provided with an optoelectronic device generating an electronic pulse for each revolution of the rotor. The pulse of one optoelectronic device is applied to the start input of a start-stop counter. The pulse from the other device is applied to the stop input of the counter and the pulse-counting input receives its signals from a frequency multiplier connected to the frequency generator.

Abstract: An apparatus for rotatively driving a turn table comprising a motor including a rotor having an arrangement of a plurality of permanent magnet poles such that north and the south poles are alternately disposed in a circle on the turn table and a stator provided to be opposed to the arrangement of the permanent magnet poles and including three stator pole means for electromagnetically driving the rotor, three saturable core coils provided to be opposed to the rotor and disposed to bring about a phase difference of 120.degree.

Abstract: A motor-driven turntable supports, for rotation therewith, a concentric ring having a plurality of permanently magnetized poles of alternate polarity symmetrically disposed along its periphery. A magnetizable core includes a pair of pole pieces having spaced surfaces defining an air gap across which magnetic flux is directed when a winding on the core is energized with alternating current. The magnetizable core is fixedly mounted such that the permanently magnetized poles pass, a seriatim, through the core gap when the turntable is rotating. The magnetized ring and the energized core form a synchronizer which opposes deviations of the turntable speed from a predetermined speed corresponding to the winding energization current frequency divided by half the number of the poles. A capacitor is connected in series with the synchronizer winding for establishing a load which exhibits a resonance at the winding energization current frequency.