Abstract: A power pack for a power tool. The power pack includes an electric motor configured to drive a power tool. The power pack also includes a motor controller with a relay circuit communicating with the electric motor. The relay circuit has a switch that may be connected to a power supply, whereby the power supply powers the electric motor. The power pack also comprises non-transitory computer-readable storage media having computer-executable instructions for monitoring operation of the power pack. When executed by at least one processor, the computer-executable instructions cause the at least one processor to: monitor input data relating to operation of the power pack; determine, based at least in part on the input data, that operation of the power pack deviated from an ideal state; and, based on the determination of deviation, cause the switch to electrically disconnect the electric motor from the power supply.

Abstract: A numerical controller suppresses change of a axis speed to be slow even when a lookahead distance varies with small steps. The numerical controller includes: a lookahead unit that looks ahead a plurality of instruction blocks from an NC program; an analysis unit that analyzes the looked ahead instruction blocks and creates motion instruction data; a target speed calculation unit that calculates a target speed of the axis based on a lookahead distance; an interpolation unit that generates interpolation data based on the motion instruction data and the target speed; and a servo control unit that controls a motor based on the interpolation data. The target speed calculation unit refrains from recalculation of the target speed when a change of the lookahead distance is within a margin.

Abstract: Systems and apparatus relating to motor control (e.g., for thermal transfer printing) include, according to at least one implementation, a motor control system including: a position controller to receive a demanded position (PD) input for controlling a motor; a torque controller coupled with the position controller, the torque controller to receive a torque bias (TB) input for controlling the motor; and a feedback circuit coupled with the torque controller and the position controller; wherein the feedback circuit is configured and arranged to combine an output from the position controller, the output being generated based on the demanded position (PD) input, with the torque bias (TB) input to generate a torque demand (TD) input to the torque controller.

Abstract: Transport apparatus for circumferentially transporting objects (22) along a circumferential transport lane (10), in particular, for a printing machine, having—at least one transport slide (20), to which an object (22) is mountable, and at least two processing units (15, 16) for processing an object, which are arranged along the transport lane (10), wherein each transport slide (20) comprises an individual drive (25) for moving the respective transport slide (20) along the transport lane (10), wherein each individual drive (25) includes a stepper motor (25) for moving the respective transport slide (20) along the transport lane (10) and for positioning the transport slide (20) at one of the processing units (15, 16), and that a central control unit (40) is present that is configured, for moving the transport slide (20) and for positioning the transport slide (20) at one of the processing units (15, 16), to output a digital positioning instruction for the stepper motors (25).

Abstract: A numerical control device includes a command analysis unit, an acceleration calculation unit in reversing operation, a velocity control unit, and an interpolation unit. The acceleration calculation unit in reversing operation is configured to calculate the acceleration of the drive shaft before and after the reversing operation when reversal of the commanded path of the drive shaft based on the commanded data is detected by the velocity control unit.

Abstract: Methods, systems, and computer-readable medium storing instructions for turning a cutting drum of a mining machine at a maintenance speed. One method includes receiving, at a controller, input signals from an operator interface, the input signals including a signal to initiate turning of the cutting drum at the maintenance speed, and transmitting, in response to the input signals, control signals from the controller to a cutting drum turning mechanism included in the mining machine, the control signals instructing a switch included in the cutting drum turning mechanism to electrically couple a cutter motor and a variable frequency drive.

Abstract: The present invention relates to a door drive, in particular a garage door drive, with a door control and with a programming unit for programming the door control during operation and/or maintenance of the door drive. In accordance with the invention, the programming unit is configured as an external device, wherein for operation and/or maintenance of the door drive a data transmission connection can be established between the programming unit and the door control.

Abstract: An automotive electric motor speed control system may include at least one electric motor adapted to cause a moveable element to move, a DC/DC power converter configured to output a voltage to the at least one electric motor that increases to a desired value and subsequently decreases to control the movement of the moveable element, and a controller configured to control the rate of voltage increase and voltage decrease output by the converter.

Abstract: A starting method and system for a motor where the motor may be started as an induction motor by applying a magnetizing current to build flux through the stator, with the field current set at the maximum permissible exciter stator current (i.e., the current that will cause rated no-load current in the main field at the transition speed). The motor stator currents will be maintained at a value that allows the motor to generate sufficient breakaway torque to overcome any stiction. At a specific transition speed or after a period of time, the drive will initiate a transition from induction motor control to synchronous motor control by removing the initial magnetizing current, and a field current is then applied to the motor through the DC exciter. Once this transition is completed, the drive may ramp up to the desired speed demand.

Abstract: A motor control device includes a recording module and a controlling module. The recording module has a revolution speed table recording a plurality of predetermined revolution speed values. The controlling module receives a reference revolution speed control signal and measures the reference revolution speed control signal to correspondingly generate a reference measuring value. The recording module records the reference measuring value corresponding to one of the predetermined revolution speed values in the revolution speed table.

Abstract: Control of rotational speed of a direct current multi-phase brushless motor is provided using an apparatus and method that works at low speed but does not depend upon Hall effect sensors. An apparatus for accelerating rotation of the motor shaft has a power stage circuit coupled to a back Electromotive Force (EMF) sensor circuit and a microprocessor. The power stage pulses at a duty cycle less than 100% under control of the microprocessor. The back EMF sensor circuit measures an order with respect to voltage of at least one phase relative to one or more other phases during off-time. The microprocessor determines one or more phases to be pulsed, and the polarity of the pulses based on the measured order. A method for sustaining rotation pulses the phases, measures order with respect to voltage of at least one phase relative to one or more other phases, and updates commutation state based on the measured order.

Abstract: A motor control method/device is provided in which a speed change during a deceleration period is stabilized in performing a speed feedback control of a motor. In the motor control method/device, the speed feedback control is performed such that a speed of a body driven by the motor is consistent with a predetermined target speed. A deceleration directive corresponding to time elapsed since a predetermined deceleration control start timing is generated as the target speed using a deceleration function of the elapsed time, to perform the speed feedback control based on the deceleration directive, during a deceleration control period. The deceleration control period starts from the deceleration control start timing and ends when the driven body is stopped. The deceleration function monotonically decreases from the deceleration control start timing until the deceleration directive becomes zero (0) and its derivative is a monotonically decreasing or increasing function or a constant.

Abstract: Arrangements and methods for implementing a “spin-down policy” for HDD motors that is “smart”, flexible and admirably achieves an objective of ensuring prolonged motor life as just discussed. To this end, one specific implementation involves (among other things) the addition of a dedicated cache that acts as a buffer element of sorts for writing or obtaining data during a period when a motor may be spun down, especially (but not necessarily exclusively) in instances when a notebook needs to be running for a large portion of the day. Other analogous implementations are of course possible that would achieve similar ends.

Abstract: A method is employed to eliminate undesired velocity reversal in a motion profile. A start speed, a start acceleration, a speed limit, an acceleration limit, a deceleration limit, an acceleration jerk limit, and a deceleration jerk limit are programmed for the motion profile. A critical jerk value needed to avoid velocity reversal associated with the motion profile is calculated. The critical jerk value is compared to the programmed deceleration jerk limit. The larger of the critical jerk value and the programmed deceleration jerk limit is set as a computed maximum deceleration jerk limit for use with the motion profile. In this manner, the computed maximum deceleration jerk limit will never be lower than the critical jerk and undesired velocity reversal is eliminated.

Abstract: Control of rotational speed of a direct current multi-phase brushless motor is provided using an apparatus and method that works at low speed but does not depend upon Hall effect sensors. An apparatus for accelerating rotation of the motor shaft has a power stage circuit coupled to a back Electromotive Force (EMF) sensor circuit and a microprocessor. The power stage pulses at a duty cycle less than 100% under control of the microprocessor. The back EMF sensor circuit measures an order with respect to voltage of at least one phase relative to one or more other phases during off-time. The microprocessor determines one or more phases to be pulsed, and the polarity of the pulses based on the measured order. A method for sustaining rotation pulses the phases, measures order with respect to voltage of at least one phase relative to one or more other phases, and updates commutation state based on the measured order.

Abstract: Arrangements and methods for implementing a “spin-down policy” for HDD motors that is “smart”, flexible and admirably achieves an objective of ensuring prolonged motor life as just discussed. To this end, one specific implementation involves (among other things) the addition of a dedicated cache that acts as a buffer element of sorts for writing or obtaining data during a period when a motor may be spun down, especially (but not necessarily exclusively) in instances when a notebook needs to be running for a large portion of the day. Other analogous implementations are of course possible that would achieve similar ends.

Abstract: A system controls an induction motor driven by a power inverter circuit. An operational amplifier circuit is operatively connected to the power inverter circuit and operative therewith for sensing DC current and controlling acceleration and deceleration of the induction motor. The operational amplifier circuit includes a first operational amplifier operative in a motoring mode to have a positive polarity output and remain substantially at zero during a regeneration mode. A second operational amplifier circuit is operative in a regeneration mode to have a negative polarity output and remain substantially at zero in a motoring mode.

Abstract: The present invention discloses an apparatus for compensating for a speed error of a motor which can reduce a speed ripple of the motor resulting from load characteristics, and which also can reduce vibrations and noises. The apparatus for compensating for the speed error of the motor divides a rotational section corresponding to one complete revolution of a rotor of the motor into a plurality of preset rotational sections, determines a speed compensation value in each divided rotational section on the basis of a difference value between a reference speed and a previous estimated speed, and compensates for the speed error of the motor on the basis of the speed compensation value.

Abstract: A method for determining an effective resistance of a voltage controlled DC motor having a nominal resistance includes driving the DC motor with a signal so that the DC motor has a targeted acceleration, and sensing an effective acceleration of the DC motor. The effective resistance of the DC motor is determined as a function of the nominal resistance, the targeted acceleration and the effective acceleration.

Abstract: A method and an apparatus for precisely controlling the rotation speed of a spindle motor in an optical system according to a given condition are provided. The method involves counting in response to a clock signal widths of first and second logic states of an input signal, which varies with rotation speed of the spindle motor, when an operation control command is issued, comparing a predetermined reference value with a count value for one check cycle, and outputting the comparison result; and controlling the constant linear velocity of the spindle motor in response to the comparison result.

Abstract: The present invention is a drive control device for controlling an electric rotational actuator which moves the driver, including: a reference comparison signal generation circuit; a detection circuit for detecting the speed of the actuator and outputting this as a detection signal; a speed designation circuit of the actuator; a rotation control circuit of the actuator; and a phase comparison circuit for comparing the phase of the reference comparison signal and the phase of the detection signal and outputting the comparison result to the rotation control circuit; wherein the rotation control circuit controls the speed of the actuator to conform with the speed designation based on the phase comparison result.

Abstract: A fly-fishing reel has a reel body with a reversible pawl and an arbor. A spindle shaft with a gear rotates on the arbor, the gear and pawl limiting the direction of rotation. A spool and lockably engaged drive plate rotate on the spindle shaft and are secured thereon by a drag capsule which attaches to the spindle shaft. Tightening the drag capsule on the spindle shaft forcibly engages friction surfaces on the spindle shaft, the spool, the drive plate, and the drag capsule to provide an adjustable dual disk drag mechanism, as well as securing the drive plate and spool together. The spool can be readily replaced with a different spool and the spools are preferably reversible on the spindle shaft. A winding handle is attached to the drive plate to provide direct-drive action, or is attached to the drag capsule to provide a non-return action.

Abstract: A multiphase motor has a plurality of ferromagnetically isolated stator electromagnets distributed about an axis of rotation. Successive ranges of speed during which the motor can be expected to operate are defined. A specific subset of the electromagnets is associated for each speed range, each specific subset comprising a different combination of electromagnets. Respective voltage magnitudes to be applied to each phase winding for each defined speed range are predefined. The motor speed is sensed throughout motor operation. In each defined speed range, only the electromagnets of the associated subset are energized, each of the energized electromagnets having applied thereto a different predefined voltage magnitude.

Abstract: Control of a motor in a device in which a mechanism is driven using the motor as the power source is achieved by providing velocity servo-control means for outputting first command information regarding the motor based upon a preset velocity profile and information relating to velocity of the mechanism, and position servo-control means for outputting second command information regarding the motor based upon a preset position profile and information relating to position of the mechanism. A motor driving signal is generated, based upon the first and second command information, in a region in which the mechanism is to be accelerated in the velocity profile. As a result, target-velocity attainment time is shortened and velocity fluctuation after attainment of the target velocity is reduced.

Abstract: A motor control apparatus capable of accelerating the motor speed to a target speed and stabilizing the motor speed in a short time is disclosed. The motor control apparatus includes a speed detection unit which outputs a signal according to the speed of the motor (or movable unit which uses the motor as a drive source). It also includes a control unit which applies, during the acceleration control of the motor to a target speed, an electric brake to the motor when the speed detected based on the signal from the speed detection unit exceeds the target speed.

Abstract: A device for supplying energy by means of a first DC voltage source e.g. in the form of a DC voltage bus, a drive system comprising several electric motors is connected to said DC voltage bus. The electric motors are comprised e.g. in a number of yarn feeding devices co-acting with a weft insertion system in a shuttleless weaving machine for producing a woven fabric having a multi-colour pattern. The electric motors operate with energy consumption function phases (start and acceleration) and with energy generating function phases (deceleration or braking). The first DC voltage source is associated with at least one second DC voltage source via a variable voltage converter.

Abstract: A motor control apparatus capable of accelerating the motor speed to a target speed and stabilizing the motor speed in a short time is disclosed. The motor control apparatus includes a speed detection unit which outputs a signal according to the speed of the motor (or movable unit which uses the motor as a drive source). It also includes a control unit which applies, during the acceleration control of the motor to a target speed, an electric brake to the motor when the speed detected based on the signal from the speed detection unit exceeds the target speed.

Abstract: To minimize the energy required for operation of a rail vehicle, in a drive system that has an intermediate circuit converter 1 and a three-phase motor 7 fed by it, the intermediate circuit voltage in the intermediate circuit 12 and/or the magnetic flux in the drive motor 7 are optimized to correspond to the actual operating requirements, including, if necessary, the energy expenditure for the auxiliaries 9 that are provided to cool the components.

Abstract: An electric scooter having batteries concealed below the standing platform in a multipurpose battery pan, an anti-lock brake, a dual suspension, a stow and carry feature, integrated electronics including brake control, throttle control, safety measures and theft protection. The dual suspension scooter includes a chassis; a steering column; a front wheel rotatably mounted on a front axle assembly; a rear wheel rotatably mounted on a rear axle assembly; a front cantilevered suspension mechanism mounted between the steering column and the front axle assembly; and a rear suspension mechanism mounted between the rear end of the chassis and the rear axle assembly.

Abstract: A wheel module for the control of the braking force on a wheel of a vehicle with an electrically controlled braking system (EBS), in which the need for data transfer to other wheel modules, or to a central module, if present, is reduced considerably. All magnitudes required for an ABS regulation of a wheel such as, for example, vehicle reference speed, are calculated directly in the wheel module according to the invention, so that these magnitudes need not be transmitted from a central module via a data bus.

Abstract: Torque is distributed by calculating first and second torque commands using a requested torque and a ratio of speeds of first and second wheels and limiting them in accordance with respective torque command approved ranges and approved change rates; converting the limited torque commands to horsepower commands and limiting them in accordance with respective horsepower command approved ranges and approved change rates; and converting the limited horsepower commands to present torque commands. Maximum horsepower available is determined by using an engine speed to determine a nominal amount of available horsepower; applying a desired load status signal and an actual engine load status signal to a proportional-integral A regulator; and using the nominal amount of available horsepower and an output signal of the regulator to determine the maximum amount of available horsepower.

Abstract: A board transfer unit for transferring a printed circuit board on which electronic components are mounted. The board transfer unit has sensors for detecting the length, width, and thickness of the board. The board weight is calculated based on the detected data from the sensors. The board transfer unit also receives information on types of components mounted on the board from a machine in the previous process. Optimal acceleration and deceleration rates are selected from previously prepared data based on the board weight and the types of components mounted in the previous process. Accordingly, the board transfer unit realizes the optimal board transfer corresponding to diversifying board weight and mounting conditions.

Abstract: A process and apparatus for positioning an object being moved along a path to a destination using a pole changing three-phase induction motor having at least two fixed driving speeds. The object is initially accelerated along the path of movement to the highest driving speed of the motor, during which the acceleration curve is determined and stored. The acceleration data is then used to calculate the location along the path in advance of the destination at which the motor is switched off and braked until reaching the next lower driving speed, whereupon the motor is operated at the next lower driving speed for a predetermined path length. The motor is then again switched off and braked until its driving speed reaches zero closely proximate the destination, at which point a motor in a gear assembly attached to the motor is operated for final low speed positioning of the object at the destination with a high degree of accuracy.

Abstract: A PWM speed regulating apparatus for DC elevator comprises a rectifier-filter (1), voltage suppressor (2), chopper voltage regulator (3), system controller (4) and a driving protector (5). The speed of DC motor is regulated by a pulse width modulating mode so that the current of the motor is maintained continuously and the ripple of current and torque is lower, and which ensures a good riding quality and a high floor arrival accuracy.

Abstract: The invention relates to a method for controlling the speed of electric drives, in particular for machine tool controllers, acceleration shocks to the gear mechanism and machine being limited. To this end, control data are read in a multi-block handling procedure and prescribed desired speeds are approached as a speed upper-limit to be maintained as far as possible, and local speed limitations are approached in the form of target speeds at defined target points within the scope of the look-ahead procedure with small acceleration changes within the limits of the maximum permissible jolt. In this context, a speed-independent acceleration limitation can be left at a constantly high maximum value.

Abstract: In a method of rotating a rotary member on a balancing machine into balancing positions in first and second balancing planes, after the unbalance measuring run the rotary member is braked and thus rotated into the balancing position in the first balancing plane, with the braking deceleration being measured. The rotary member is then accelerated to a rotary speed of at most 80 rpm for rotation into the balancing position in the second balancing plane. The rotary member is then braked so that the braking travel resulting from the measured deceleration corresponds to the differential angle still remaining as far as the balancing position in the second balancing plane.

Abstract: The present invention provides the following rotation control method for reducing energy consumption of a motor driving a disk. In a constant speed mode, a supply voltage V1 for driving the motor at a constant speed N1 is selected; however, at a lower constant speed N2, a supply voltage V2 lower than V1 is selected. In an acceleration mode for accelerating the motor speed from N2 to N1, a higher supply voltage than V1 is selected just before starting acceleration, and then V1 is selected after the acceleration. In a speed deceleration mode for decelerating the motor speed from N1 to N2, a lower supply voltage than V1 is selected just before starting deceleration, then the supply voltage V2 is selected after the decleration.

Abstract: A control device for controlling the drive of a stepping motor included in an electronic apparatus as a drive source is disclosed. The stepping motor is totally controlled by a microprocessor and driven by a motor driver. A memory stores control data for the acceleration, constant-speed drive and deceleration of the motor. A motor controller controls the motor via the motor driver with the control data loaded without the intermediary of the microprocessor. A constant-speed rotation end signal is input to the motor controller from either a CPU (Central Processing Unit) or an external unit as a repeat signal. When the repeat signal is "0", the control data stored in the memory and assigned to constant-speed drive is repeatedly loaded a preselected number or times, causing the motor to rotate at a constant speed. When the repeat signal is "1", the above control data is repeatedly loaded until the repeat signal changes to "0".

Abstract: A motor speed control device, preferably for use in a camera, controls a motor to rotate at a constant speed in accordance with a pulsed signal output from a motor speed detector, such as a photointerrupter. To overcome the control problems that occur when the motor abnormally stops rotating, preventing generation of pulsed, the motor speed control device includes a timer that measures elapsed time from a most recent pulse. When the elapsed time exceeds a predetermined value, the motor speed control device accelerates the motor so that control of the motor at a constant speed can continue.

Abstract: A position command method and apparatus for shortening the acceleration and deceleration times of a servo controlled apparatus by effectively utilizing the torque of the controlled apparatus. A value of speed per unit time is developed on the basis of speed and position data, and a constant speed or an acceleration or deceleration function processing may be selectably performed. In the position commanding method and its unit of the present invention, the deceleration stop distance of output speed is computed at all times or is held as a list data as described above and moreover is compared with a residual distance XR. Consequently, the deceleration stop distance does not have to coincide with the residual portion from the acceleration command, and the acceleration/deceleration curve alone can be realized in an independent form. Also, the speed change can be made smoother by correcting the cross point of independently formed acceleration and/or deceleration curves defining a corner section.

Abstract: Disclosed is a method for driving a printer carrier. One power source is connected via a constant current circuit to the carrier motor. Data storing means stores the current command data corresponding to the acceleration, constant speed printing and deceleration of the carrier motor. According to the method, the current command data from the data storing means is latched in synchronism with a clock signal. The latched data is converted to a current reference voltage. The output current of the constant current drive circuit is varied in accordance with the current reference voltage. Changing the current command data as desired makes it possible to adjust freely the torque of the carrier motor for acceleration and deceleration on a constant voltage from one power source.

Abstract: Motor-control device for an image forming apparatus includes a motor, an encoder, a microcomputer, and a driving circuit. The encoder generates a pulse signal in response to rotation of the motor. The microcomputer includes a CPU, a RAM and a ROM. The CPU detects actual rotational speed of the motor based upon the pulse signal generated by the encoder. The CPU cyclically provides a driving signal by comparing the actual rotational speed with a predetermined target rotational speed of the motor. An operating cycle is proportional to a cycle of the pulse signal generated by the encoder. The driving circuit drives the motor based upon the driving signal provided by the CPU. The CPU determines the operating cycle based upon the predetermined target rotational speed. The CPU also determines whether the motor condition is normal or abnormal by comparing the driving signal with a predetermined reference driving signal.

Abstract: A drill motor control for periodically varying the rotational speed of a drill to increase the cutting efficiency of the drill bit is disclosed. The speed of the drill is made to vary according to a predetermined cycle such that the drill bit is permitted to bite into the material being drilled at lower speeds, and then the speed is increased to a point where maximum cutting efficiency is achieved. The drill motor control may either be a stand alone apparatus into which a conventional drill is plugged or alternatively may be incorporated into the drill itself. A closed loop control system which senses drill motor current may be utilized to cause the drill motor to slow down as current to the motor decreases when the drill bit ceases its cutting action such as when glazing occurs or when the drill bit has cut completely through the material being drilled. The drill motor control is also useful when the drill is being used as an electric screwdriver.

Abstract: A control arrangement for controlling the power supplied to an electric motor connected to a rotary member to drive same in rotation by way of a belt drive, to accelerate the rotary member to a given speed and to brake it in a slip-free manner provides that a signal which is proportional to the speed of rotation of the rotary member is compared to a signal which is proportional to the speed of rotation of the motor. The supply of power to the electric motor is correspondingly controlled in dependence on the result of the comparison operation.

Abstract: An image reader including a control apparatus adapted to control a drive motor such that an image scanner can be moved at a desired speed in its forward stroke and at a higher speed in its backward stroke.

Abstract: The system includes a plurality of parallel-connected power field effect transistors arranged for connection in series with the traction motor with a common control circuit connected to the gate electrodes of the field effect transistors to control the on-off cycle of conduction through the field effect transistors. A plurality of parallel connected power diodes are arranged for reverse connection in parallel with the traction motor to serve as freewheeling diodes. The diodes are physically positioned apart from one another and distributed in position among the field effect transistors and each diode is positioned in a similar manner with a group of associated field effect transistors for ease of transfer of current flow between the diode and the associated field effect transistors.

Abstract: An improved magnetic tape drive having high performance specifications is achieved by microprocessor control of the capstan motion. Possible velocity profiles are stored in read-only memory and are selected on the basis of new input commands and last previous actions taken, whereby excitation of mechanical resonance inherent in the system is avoided.

Abstract: A motor driving circuit in which the opposite ends of the motor driving coils of a video tape recorder (VTR) capstan motor are shorted by a group of switching elements when a control input voltage generated from a rotation detection/oscillator is in a predetermined range.

Abstract: In this drive control the regulating circuits for the rotational speed of a drive motor and of an eddy current brake are matched in their static and in their dynamic behavior so that a common regulator may be used for both regulating circuits. The matching is achieved by interposing a current regulation circuit for regulating the excitation current of the eddy current brake to the rotational speed regulating circuit. The output of the common regulator is supplied via a linearization member as a reference value to a regulator in the current regulation circuit during the deceleration phase. During the acceleration phase the output of the common regulator is supplied to a matching element matching the variation of the torque to the variation of the torque during the deceleration phase with respect to time. The output of the matching element is connected to the control member of the drive motor via a linearization member. By means of the linearization members the characteristics of a d.c.

Abstract: A three level motor speed control for a device such as a magnetic disk drive requiring a closely regulated running speed provides for acceleration, deceleration, obtaining close speed regulation and maintaining speed regulation of a rotating device during operation. The first level control provides acceleration or deceleration while checking velocity each eighth revolution and the second level control uses single revolutions to measure speed over an accurate rotational distance to obtain close speed regulation. Both level one and level two are controlled by the device controller. During run conditions with no error signal, a third level of control of the closely regulated velocity is maintained by separate hardware circuits which frees the processor for other uses. An error condition forces control to level one for re-establishment of the regulated running speed and a command to stop the drive forces control to level one for deceleration and stop procedures.