Abstract: A motor network control system is provided which is capable of reducing the wiring length of a power cable and in which upon replacement of a motor or an inverter of a specific motor unit, no adverse influence is exerted on the other motor units. A power cable 7 and a communication cable 8 connecting between a plurality of motor units 30a-30c, each of which includes a motor 4, an inverter 5 and a communication part 6, extend successively from a power supply 1 and a network control computer 2, respectively, to the respective motor units 30a-30c in such a manner that the motor units are connected with each other in a cascade manner from a preceding one to a following one. In addition, each of the motor units includes a connection board 11 on which an inverter 5 and a communication part 6 are installed.

Abstract: A control device for a plurality of rotating electrical machines has a single current control device with an inverter, gate driver, and a motor controller, which supplies a control current to each rotating electrical machine allowing rotation control in response to the rotational phase of the rotor. In this control device, the current control device determines the control current of each rotating electrical machine based on the target torques and rotational angular velocities of all rotating electrical machines, and supplies a composite current obtained by combining the determined control currents for each rotating electrical machine to all rotating electrical machine. In this control device for a plurality of rotating electrical machines, the required voltage does not exceed the voltage of the power source and the peak value of the composite current does not exceed the permitted range of the inverter.

Abstract: Two motors are used to provide motion control in a transport drive system. A primary motor, or a primary and secondary motor, provides primary power for accelerated motion. PWM signals are used to drive the motors according to predetermined fixed functions related to acceleration, deceleration and hold of a load. Alternatively, during onset of large or high speed moves, the primary and secondary motors are on in tandem. During deceleration of a move, the torque provided by the secondary motor is reversed, providing active braking and ensuring the drive train remains loaded wherein backlash is eliminated. During a driver hold phase, the primary and secondary motor push against each other to actively control positioning.

Abstract: AC servo motor drives which allow several AC drives to be connected in parallel and allow for the connection and reconnection of AC servo motors to be accomplished primarily through a central processing unit (CPU). Thus, multiple AC servo motor drives may be ganged under the supervision of the CPU to provide a servo motor with multiple times the current available from a single drive and optionally redundancy in the drives. To provide necessary coordination, the required motor current magnitude and phase (current vector) are broadcast by an axis controller to the drives. This command current vector is broadcast over a high speed serial data bus which allows many simultaneous listeners (the AC servo motor drives). To protect against damage to each drive, each of the three current output terminals is preceded by an output filter. The output filters preceding the terminals permit phase by phase parallel connection of several drives in the service of one servo motor.

Abstract: A mechanism controller for controlling power to motors of a mechanism having several motors, such as a robot. Each motor has a resolver for indicating the motor position. A driver unit is associated with each motor to supply power to the motor. Each driver unit includes a monitoring unit to monitor indications from the resolver of the associated motor. In one embodiment a control unit is connected to the driver units in a series circuit to control power to the motors and to receive the monitored indications from the monitoring units. In a second embodiment, the control unit is connected to the driver units in a ring circuit, rather than in a series circuit. Preferably, each driver unit also includes a memory device, and the control unit can send commands to the driver units and receive data from the driver units in sets equal in number to the number of driver units so that the commands and data do not need to include the addresses of the specific driver units.

Abstract: A device and a process for controlling the motor drives (121) of textile machines, comprising at least one “encoder” (101), capable of controlling the number of revolutions of each motor (121), and at least one central electronic unit (111) processing the data originating from all the motor drives (121), based on an application program containing the synchronizing data between the individual motors (121) and the technological operating parameters of the textile machine.

Abstract: A motor system utilizes a master three-phase induction motor driven by a single-phase power supply which the motor has six-windings connected in a symmetrical double DELTA or double WYE configuration with appropriate running capacitors to provide when the motor is running a balanced three-phases of voltage potentials. The potentials have been tapped off to run satellite three-phase induction motors.

Abstract: An electronic system (101/102) for use in a car has an electronic control unit (10) and, in the alternative, either a passive load (11) or an active logic (12) attached thereto. The control unit (10) comprises a push-pull arrangement (20) which can provide drive signals for the load (11) as well as for the logic (12), a multiplexer (45) to alternatively forward a load drive signal of a bus signal to the arrangement (20), and a register (90) to store a mode signal. Further, the control unit (10) automatically determines whether either the load (11) or the logic (12) is attached by analyzing electrical parameters.

Abstract: In a method and device for controlling several stepping motor modules in printing or copying machines, sets of ramp data are centrally calculated in a computer in a calculation phase and are transmitted via a bus system to one logic unit each in a loading phase. The ramp data are stored in the stepping motor modules in non-volatile memories and are loaded to corresponding main memories depending on operating conditions. When a stepping motor module is operational, the current set of ramp data is transmitted by a control unit. A start signal transmitted by the control unit initiates the conversion of the set of ramp data selected in the corresponding logic unit into impulses of variable distance.

Abstract: A control system controls the movement of an object based on desired position data. The control system includes a first regulator configured to regulate the position of the object, a feed forward control configured to feed the desired position data forward to a second regulator at a lower level than the first regulator, and a modeling filter configured to receive the desired position data and to provide the desired position data to the first regulator with a predetermined time delay.

Abstract: A power steering system and induction motor load compensation algorithm or processing method for use in a vehicle. The power steering system comprises a power supply, a power steering motor, a steering subsystem, and a power steering controller coupled to the power supply. The controller processes a frequency command input corresponding to the power steering frequency requested by the steering subsystem and data contained in one or more software lookup tables to adjust the output frequency produced by the power supply to control the speed of the power steering, motor. The lookup tables are generated empirically and characterize the output power of the power supply at different system pressures over a range of motor speeds. The software lookup tables provide a power band that implements a power limiting state machine.

Abstract: A contactorless multi-motor controller is described which comprises a contactorless pump motor starter and a contactorless, reversible traction motor controller. The two controllers are mutually interactive. When the pump motor has ramped up to full voltage, a function block on-board said pump motor control circuit detects this condition and enables the tramming operation of the traction motor.

Abstract: A motor control apparatus, which can control the speeds of a plurality of motors with nearly no speed variations until the final target speed is reached, includes a target speed setting circuit for dividing the speed range of the motors up to the final target speed into n steps (n is an integer and n.gtoreq.2) to set a target speed, and setting the next divided target speed after all the motors have reached the current divided target speed.

Abstract: A number N of AC machines, such as motors or generators, are independently controlled by a control system having 2N+1 phases, having N orthogonal sets of phase components. In a particular application, a hybrid vehicle including a generator and an induction motor are independently controlled by a five-phase controller having two independent sets of mutually orthogonal components. Each set of components controls one of the machines, and has no net effect on the other machine(s).

Abstract: A three-phase generator boost circuit for augmenting the back electromotive force produced by a spindle motor of a disk drive is disclosed. First and second nodes provide normal connection to a source of DC voltage for the spindle motor and a second motor connected between the first and second nodes. A commutator is connected to a sequencer to operate the spindle motor. In the event of catastrophic shutdown, two of the lower commutator switches are operated to short circuit the two stator coils having the highest and lowest voltages to store energy in the coils. The commutator switches are then operated to discharge current through the nodes to a storage capacitor for the second motor.

Abstract: In a displacement machine for compressible media having at least two rotors (14a-c) which are configured as profiled bodies and whose profiles engage with one another in the manner of gearwheels during rotation, the individual rotors are respectively driven by their own electric motors (9a-c) and are kept synchronous in rotational speed and angular position by electronic closed-loop and/or open-loop control units (1; 25a-c) in accordance with the transmission ratio of the displacer unit stage. The electronics can be employed for monitoring further operating data of the pump and also for matching the pump output by changing rotational speed. It can also be used as an overload protection. The rotational speeds and rotational attitudes of the rotors are controlled individually and independently of one another, the required attitude values being specified to the individual control units (25a-c) by means of a main control unit (1).

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: Multiple motion controllers for controlling servo motors are connected by a digital communications link so that controlled axes of the motion controllers may be slaved together regardless of their physical proximity. A given controller broadcasts position or command signals on the communications link in response to a request report message from any other controller. A second request report message may stop the broadcasting to conserve link capacity. Time shifting implicit in the link messages is corrected by estimating the velocity of the master axis and extrapolating the position to the local axes' time of updating.

Abstract: A system for powering a multicurrent locomotive having 2N motors where N is greater than or equal to 2, the system comprising 2N pairs of voltage converters respectively associated with the 2N motors, each motor M.sub.i being powered by means of an inverter connected to the terminals of a parallel capacitor. When the locomotive is powered with AC, then each of the pairs forms a 4-quadrant converter in which the two portions are implemented by the secondary winding of a transformer whose primary winding is connected directly to the terminals of the AC power supply. When the locomotive is powered with DC, the switches serve to use the voltage converters either as voltage-lowering choppers or as voltage-raising choppers. The power supply system is designed in such a manner that in the event of a converter or an inverter failing, it suffices to isolate the failed element to conserve the functions that remain.

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: 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 modular electrical system (10) supplies power to and controls a plurality of electric motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) associated with a plurality of drive units folding or extending rows in a telescopic seating system, comprising the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4), a control panel (12) removably communicating with the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) directing incoming current to drive the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) in a predetermined direction, a dual receptacle (18) communicating with the control panel (12), and a switch (26) terminating in a plug (30) removably communicating with the dual receptacle (18).

Abstract: This invention is for incrementally controlling energizing and de-energizing of at least two electrical motors in which motor armatures are mechanically coupled to a single mechanical member and in which motor stators are mechanically referenced to a second mechanical member. By energizing and deenergizing two or more electric motors of different force and torque capability coupled in this manner it is possible to provide increments of force and torque as small as the incremental capability of the smallest motor and to provide a large number of force and torque increments which can approximate a smooth control of force and torque in forward and reverse directions. The type of motor used for this invention is a multiple-two-node-open-circuit-armature-winding motor as disclosed in the referenced patents. This type of motor offers various levels of energizing the motor to the full force and torque capability.

Abstract: The driving device comprises two single-phase stepping motors (1, 2), each having a different preferential direction of rotation. The bidirectional drive is achieved by selectively feeding one or the other of the two motors.

Abstract: Multiple motion controllers for controlling servo motors are connected by a digital communications link so that controlled axes of the motion controllers may be slaved together regardless of their physical proximity. A given controller broadcasts position or command signals on the communications link in response to a request report message from any another controller. A second request report message may stop the broadcasting to conserve link capacity. Time shifting implicit in the link messages is corrected by estimating the velocity of the master axis and extrapolating the position to the local axes' time of updating.

Abstract: A modular electrical system (10) supplies power to and controls a plurality of electric motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) associated with a plurality of drive units folding or extending rows in a telescopic seating system, comprising the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4), a control panel (12) removably communicating with the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) directing incoming current to drive the motors (M.sub.1, M.sub.2, M.sub.3, M.sub.4) in a predetermined direction, a dual receptacle (18) communicating with the control panel (12), and a switch (26) terminating in a plug (30) removably communicating with the dual receptacle (18).

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: A method and firmware motor calibration system for measuring average system voltage of operating electric motors and time of movement between physical stops of mechanical structures coupled to the output shafts of the electric motors. The system calibrates motors arranged to operate as hybrid closed and open loop motor control systems. Data concerning position of the shafts is determined for the closed loop motor control systems.

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: An elevating system especially designed for raising and lowering battens used in stages. The elevating system preferably uses two or more winch assemblies with synchronous motors coupled together in parallel to an AC inverter to provide smooth, ramped starting and stopping of the winch assemblies as well as torque boost, speed boost, and electric braking. Each winch assembly is provided with numerous safety features such as overload and underload protection, automatic releveling of the batten, thermal overload protection and cable drum lock protection.

Abstract: An electrical composite rotating machine capable of developing output shaft speeds in excess of the synchronous speed of a single motor without resort to gearing or frequency changers. An a-c electric motor is equipped with a rotor which is at one end connected to a rotatable field structure of a second motor. When the first two-pole motor operates at a nominal shaft speed of 3600 rpm, it also drives the field structure of the second motor at 3600 rpm. When the field of the second two-pole motor is activated, the rotor of the second motor rotates at a speed of 3600 rpm relative to its field structure, thus developing an output speed of 7200 rpm. With different numbers of poles in the respective motors, different shaft output speeds can be achieved.

Abstract: A heat engine operates an alternator that supplies electrical power to an electric continuously variable transmission for driving at least one ac motor through a differential to multiple wheels or to multiple independent ac wheel motors in an automobile, bus or truck. A heat engine control operates in a closed-loop power mode and decouples heat engine speed from motor speed, allowing the heat engine to produce required power at an operating speed and throttle position, or fuel injector duty cycle, that maximizes fuel economy and minimizes engine emissions. An energy storage unit (e.g., a battery, flywheel, ultracapacitor, superconducting magnetic energy storage device, or combination thereof) provides electrical energy to the electric drive system during vehicle accelerations and further reduces peak power demands on the heat engine. Advantageously, energy is recovered during vehicle deceleration and braking; and the recovered energy is used to recharge the energy storage unit.

Abstract: Drive control units are provided each for one of plural drive shafts for controlling driving of the drive shaft in response to an individually imparted set value. A state parameter generation section generates, for each of the drive shafts, a parameter representing a state concerning a predetermined object of harmonization control among drive control states of the respective shafts produced by the drive control units. As the object of harmonization control, a desired factor may be selected depending upon necessity for the harmonization control. A position loop gain or a velocity loop gain, for example, may be selected as the object of harmonization control. A reference parameter generation section generates, responsive to the generated parameter representing the drive control state of each drive shaft, a reference parameter to be used as a reference of the harmonization control.

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 rotating display element which is provided with a display surface member having four display surfaces which are selected by rotating the display surface member, and a display unit which uses the display element. The display surface member has incorporated therein a permanent magnet type motor mechanism and is driven by the permanent magnet type motor mechanism. The rotor of the motor mechanism has first and second double-pole permanent magnet members, and its stator has first and second magnetic members having wound thereon first and second exciting windings, respecitvely. The display unit has first and second power supply means for supplying power to the first exciting winding motor mechanism and third and fourth power supply means for supplying power to the second exciting windings.

Abstract: A rotary element (10) such as a robot arm is to be positioned by an actuating drive to a position determined by a desired value signal. An angle pick-off (20) provides an actual value signal. A first controller (36) provides a first controller output signal through an adaptive transfer element with limitation. The first controller output signal is applied to a first torque motor (18) the rotor of which is directly connected with the rotary element (10). A second controller (38) provides a second controller output signal, which is applied to a second torque motor (22). The second torque motor (22) is connected with the rotary element (10) through a step down system (26) and a resilient coupling member (30). A coupling path (40) with an integrator applies a trimming signal dependent on the input of the first torque motor (18) to the input of the second torque motor (22).

Abstract: The mechanical stabilization system for a support comprises a working rotor mounted on the support by means of bearings and fixed to a working member having at least one parameter associated with the rotation of the working member and which is variable as a function of time. A reaction rotor is concentric with the working rotor and is mounted on the working rotor by means of bearings and is fixed to a reaction inertia member. A first servo-controlled electric motor is interposed between the working rotor and the reaction rotor and serves to drive the working rotor and the reaction rotor in opposite directions of rotation. A low power second electric motor is interposed between the working rotor and the support and is servo-controlled in such a manner as to reposition the reaction rotor and correct for drift in the correcting motion of the reaction rotor, due in particular to friction in the bearings.

Abstract: In a circuit arrangement for textile machines having a plurality of identical aggregates, each having a drive motor (1), particularly for spinning machines having individually driven spindles, respective motor bars are provided for the connection of each aggregated. Each motor bar is connected with a ground plate which is provided with energy supply lines and has a predetermined number of bar connectors. At least the energy supply lines of a minimum of two ground plates are connected with each other and with a connecting line (9) common to them which leads to a central energy supply device (2) of the machine.

Abstract: An industrial robot control device for use in an automobile manufacturing line for instance. The device is capable of preventing incorrect or improper operations of the machines due to a voltage drop in a power source, which occurs when a plurality of machines including the industrial robots are driven simultaneously.

Abstract: A wiper control system includes a rear wiper control circuit associated with a front wiper control circuit. The wiper drive signals generated in the front wiper control circuit are fed to the rear wiper control circuit. The rear wiper control circuit derives a rear wiper drive timing on the basis of the occurrences of the front wiper drive signals. The rear wiper driving frequency is generally lower than that of the front wiper driving frequency. The lower rate of the rear wiper driving frequency relative to the front wiper driving frequency is preferably variable depending upon the vehicle driving condition.

Abstract: A low-cost system for allowing manual or automatic aiming of a plurality of motor-driven devices distributed throughout an area from a common control center location. When in a manual mode, the operator may manipulate a four quadrant touch pad or a joy stick device to develop binary control signals indicative of rotational direction and the on/off state of a motor control chip associated with each of the motors. The control signals are distributed over a master bus and optionally over additional local buses to the appropriate motor control chips. In an automatic mode, the same control signals are generated to produce repetitive sweeping of the motor-driven devices through a predetermined arc.

Abstract: An electromechanical actuator includes an electric motor and a control and drive circuit mounted integrally with the electric motor. The control and drive circuit includes a serial-to-parallel converter for converting a control signal in the form of serial data into parallel data, and a device responsive to the control signal in the form of parallel data for producing a drive current or voltage for the electric motor. A system for accessing or controlling a plurality of such actuators by commands from a main controller can include a control and drive circuit which is integral with the motor itself.

Abstract: A variable speed film transport interlock control system for allowing a plurality of film audio elements to be run in synchronization with each other with at least one film element running at a different selected speed than the other elements. The system generates a modified drive signal from a standard system drive signal such that the modified signal corresponds to a speed with a fixed ratio to the speed of the standard drive signal under all operating conditions. This permits the modified signal to drive a film transport device, such as a recorder or reproducer, at a different speed than the other transport devices while maintaining synchronization with the other devices during forward or reverse, stopping and starting, high speed or low speed operation.

Abstract: In a first type of variable speed electric motor, two coaxial shafts are mounted in a housing. Two rotors are mounted on each shaft. Two stators are mounted in the housing. Each of the stators is in operative association with a rotor mounted on a different one of the shafts. The remaining two rotors are in operative association with each other and form a converter motor. In the second type of variable speed electric motor, two parallel shafts are mounted in a housing. A support is mounted for rotation around the first shaft. Two rotors are mounted on the first shaft. A stator is mounted in the housing in operative association with one of the rotors mounted on the first shaft. A third rotor is mounted on the support in operative association with the other rotor mounted on the first shaft. The support is geared to the first shaft through idler gears mounted on the second shaft.

Abstract: An electric powered vehicle or the like includes a first mechanical drive system for a first side of the vehicle and a second mechanical drive system for a second side of the vehicle. A first DC motor and a second DC motor are respectively coupled to the first mechanical drive system and the second mechanical drive system. A source of DC power is on the vehicle. The first DC motor has a first field and a first armature and the second DC motor has a second field and a second armature. The first field, the first armature, the second field, and the second armature are connected in a series circuit with the source of power. A voltage sensing relay across the first armature can detect a high voltage across the first armature to sense a loss of traction of the first mechanical drive system. A switching circuit is employed to disable the first motor from the series circuit in response to the voltage sensing relay.

Abstract: A motion control drive system for producing and controlling programmed and remote controlled machine operations by directing and controlling the performance of a rotating output shaft. The output shaft is then used to provide drive power and programmed control of various machine operations required to be controlled by a program of predetermined machine operating commands. The final program of operating commands being stored on audio magnetic sound recording tape or other audio recording media for purposes of storage and subsequent use in directing and controlling a given machine. The program of operating commands being stored on two track audio magnetic tape in the form of dual, first and second, time varying and or fixed frequency audio signals whose frequencies interact and become the function of the commands to be executed.

Abstract: In a ring spinning or other textile machine with a multiplicity of thread-winding stations each including one or more variable-speed motors, a central controller supplies periodic or continuous timing signals to respective speed setters of all stations for a predetermined progressive speed change of the associated variable-speed motors. In a specific embodiment, the timing signals are recurrent pulses for the advance of identical programs of the local speed setters whereby the several stations will follow the same routine but with possible relative staggering in time, taking individual delays due to thread breaks or the like into account.

Abstract: A rotating display element is provided with a display surface structure which has a plurality of display surfaces and is mounted on a rotor of a permanent magnet type stepping motor mechanism in a manner to incorporate therein the stepping motor mechanism. The display surfaces of the display surface structure are disposed side by side around the axis of the rotor. The rotor is provided with a double-pole permanent magnet member having north and south magnetic poles spaced apart a 180.degree. angular distance around the axis of the rotor. A stator of the stepping motor mechanism is provided with a first magnetic member having first and second magnetic poles disposed at 180.degree. intervals around the axis of the rotor, a second magnetic member having third and fourth magnetic poles disposed at 90.degree. intervals around the axis of the rotor, a first exciting winding wound on the first magnetic member and a second exciting winding wound o the second magnetic member.

Abstract: Apparatus for controlling wheel slip in a locomotive driven by d.c. motors which receive power from a diesel driven generator, has sensors which provide signals representing speeds of different driven wheels to a velocity unit. The velocity unit derives a differential signal representing the difference between the highest and the lowest wheel speeds. A sensor detects current or power in the generator output and the signal from this sensor is sampled periodically and the latest two sampled values are stored. The sampled values are compared to provide a creep reference signal. The differential signal and the creep reference signal are compared and the resulting difference signal is used to control generator output to maximize current during acceleration.

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.