Abstract: Disclosed is a speed controller of a motor which comprises a rotation sensor for generating an A.C. signal having a period in accordance with a rotating speed of a motor; speed detection device for effecting detection operations a plurality of times per round of the motor by the A.C.

Abstract: An electric shaver is provided with a motor to drive a cutter, a motor current sensing circuit, and a computation circuit which processes an output from the current sensing circuit. The computation circuit computes beard thickness, and a set range of motor rotational speed regulation according to beard thickness to lower rotational speeds for thin beards and to higher rotational speeds for thick beards, and thereby rotates the motor at optimum speeds according to beard thickness.

Abstract: A brake lathe for truing brake rotors includes a tool holder driven by a direct current motor to move a cutting tool radially with respect to the rotor axis in direct proportion to the number of turns of the drive shaft of the direct current motor. A tool feed power control circuit maintains the direct current motor at constant speed regardless of radial forces acting upon the cutting tool and includes a converter/filter circuit, a regulator circuit, a sensing circuit, and a speed control circuit. A speed selection control includes a rheostat for providing a reference voltage corresponding to a select speed. The sensing circuit compares a voltage drop across the direct current motor to the reference voltage and produces an error voltage. The speed control circuit provides a direct current power voltage to the direct current motor in accordance with the error voltage output of the sensing circuit to maintain operation of the motor at constant speed.

Abstract: A load of an electronic sewing machine is self-diagonosed by a control system to cause a DC motor to be operated under control to drive upper and lower shafts of the sewing machine. The control system includes an evaluating device to which a voltage value applied to the DC motor and a rotating speed of the DC motor, both detected, are inputted for determining a current value supplied to the DC motor and a power loss of the DC motor. These data are supplied to a fuzzy inference unit for inferring an optimum rotating speed of the DC motor. A control command signal representing an excessive degree of the actual power loss in reference to the rated power loss is outputted from the fuzzy inference unit to the DC motor for the control of the electric power to be supplied thereto.

Abstract: The specification describes a controller apparatus for a DC motor and a lamp having a filament electrically connected in parallel with the DC motor, comprising: (a) an output driver circuit for generating a DC power signal, where the DC power signal energizes the DC motor; (b) an AC signal generating circuit for generating an AC power signal; and a high frequency coupling transformer for so adding the AC power signal to the DC power signal that the AC power signal energizes the filament. Preferably, the controller also comprises: (a) a switching circuit for periodically preventing the DC power signal from controlling the DC motor; (b) a speed sensing circuit for determining a speed of the locomotive by measuring a back EMF signal generated by the DC motor during the time that the switching means prevents the DC power signal from controlling the DC motor; and (c) an error correcting circuit for correcting the DC power signal based on the speed of the locomotive.

Abstract: A circuit for controlling a current in a load that includes an inductive component provides a high constant gain at low frequencies, a gain roll off at medium frequencies, and a low gain above unity gain at frequencies between the medium frequencies to high frequencies so that the gain roll off of the circuit to below unity gain is provided by a pole of the inductive load component. As a result, the circuit has a bandwidth limited only by the poles of the load. The circuit has a high gain amplifier with an input connected to receive a input control signal, and a low gain amplifier with an output connected to a control element of a switching element in a current path of the load. A frequency compensation circuit is connected between an output of the high gain amplifier and an input of the low gain amplifier, and includes a high frequency current bypass path and a resistor in series therewith operative to reduce the signal input to the low gain amplifier at high frequencies.

Abstract: For operating a plurality of mechanisms with a single motor, a motor control device is provided which is capable of stably operating one of the mechanisms while reducing influence of load imparted on the motor and attributed by an operation of remaining one of the mechanisms. A CPU suitably controls or selects electrical current level provisionally ranked and stored in a ROM to a printing motor which drives a print hammer for obtaining predetermined velocity of the hammer. If the print hammer reaches its decelerating position, the CPU determines offset electrical current level and current applying period to be applied to the printing motor on a basis of the rank of the electrical current at that phase.

Abstract: A motor driving circuit capable of controlling a motor speed by a current controlled method using negative impedance is constituted by a constant-current circuit, a reference voltage generating circuit, a comparator circuit, an output driving circuit, a symmetric current circuit, and a switching circuit. The reference voltage generating circuit outputs a voltage of a value derived from addition of a reference voltage and a voltage proportional to a value of a current flowing to a motor. The comparator circuit compares a voltage outputted from the reference voltage generating circuit and a voltage at an output terminal. The output driving circuit amplifies an output of the comparator circuit. The symmetric current circuit amplifies the output from the output driving circuit.

Abstract: A flexible disk drive device includes an adjusting circuit which sets termination timing of outputting of an index signal in response to the rotating speed of a motor by adjusting charge or discharge time constant of a capacitor; a reference voltage generating circuit which includes a plurality of resistors connected in series between the power source line and the ground line and generates the reference voltage at one of the nodes of the resistor chain; and a reference voltage switching circuit which switches the reference voltage to another reference voltage upon receipt of a speed selection signal which represents a different rotating speed from a predetermined rotating speed, wherein the other reference voltage is so set that the pulse width of the index signal corresponds to a predetermined rotating angle of the motor.

Abstract: A control system for an electric vehicle comprises a motor speed detector and a sensor for detecting an accelerator angle and outputting a motor speed error command based on the difference between motor speed and a speed required by the present accelerator angle. A motor speed command is generated based on the error command and the detected motor speed. A feedback control portion outputs a torque command based on the motor speed command and the detected motor speed and the driving force of the motor is controlled based on the torque command.

Abstract: A method of operating bridge circuit for control of an inductive load is disclosed. The bridge circuit has a pair of input terminals for connection across a power source and a pair of output terminals for connection across the inductive load. Each arm of the bridge includes a transistor switch connecting an input terminal with an output terminal. Clamp circuits are connected to each pair of input and output terminals, taking inputs therefrom and responding to a transition through a predetermined voltage differential between the terminals for driving the transistor switch connecting the output terminal to the remaining input terminal, thereby limiting the output terminal to a predetermined voltage level.

Abstract: An electric shaver comprises: a current detecting circuit which detects load current of a motor; a microcomputer which samples the values detected by the current detecting circuit periodically to judge the size thereof, and the positive or negative results of the difference with the values sampled at last, to output a predetermined signal respectively responsive to the results; and a control circuit which controls the rotational speed of the motor according to the output signal from the microcomputer, whereby in the case where load current of the motor detected by the current detecting circuit is large, the microcomputer reckons that beards are thick, conversely, in the case where the load current is small, the microcomputer reckons that the beards are thin, thereby driving the motor at an optimum speed respectively.

Abstract: In connection with an automatic control device for the cleaning power of a vacuum cleaner, comprising a blower, a blower drive motor and an associated control circuit for the latter, it is proposed to provide two vacuum switches adjusted to different vacuum threshold value or one vacuum double switch presetting the two vacuum threshold values, and to drive a storage (counter, capacitor), whose output configurations determine the manner in which a phase control circuit, which is connected in series with the blower drive motor, is driven, by a corresponding configuration of the switching conditions of the said switches. It is possible in this manner, with only two existing vacuum switches, to operate the blower drive motor at a predetermined power plateau, without any switching actions, so long as the vacuum generated remains within a predetermined window.

Abstract: A control system controls a motor so that a controlled speed is maintained at an object value supplied from an external unit. The control system includes: an operation block for obtaining a difference between the object value and the controlled speed; an integrating block for integrating the difference obtained by the operation block and for outputting an integrated value; a limiting block for outputting a limited value when the integrated value obtained by the integrating block is equal to or greater than the limited value and for outputting the integrated value from the integrating block as it is when the integrated value is less than the limited value; and a control block for maintaining the controlled speed of the motor at the object value based on the integrated value or the limited value output from the limiting unit.

Abstract: An apparatus is disclosed which controls the speed of a motor driving a load. A speed controller finds the difference between a command speed value of the motor and a detected speed value of the motor and generates a command current value of the motor on the basis of the difference. A current controller controls current in the motor on the basis of a difference between a command current value received from the speed controller and a detected current value. A torque detector is mounted on the shaft, whereby the motor is connected to the load, for detecting torque acting on the shaft, and an adder adds the detected torque signal detected by the torque detector to the command current value received from the speed controller, the torque detection signal being a correction signal for controlling acceleration torque of the motor.

Abstract: There are provided a position and velocity control system for producing a velocity command signal in response to a position command signal and a signal representing a current position and velocity of a servo motor, a current control system for supplying a drive current to the servo motor in response to the velocity command signal, and a communication system for transmitting data between the two systems by means of a bilateral communication line. A servo control system is thereby separated between the current control system and the position and velocity control system and connected to each other through the communication system.

Abstract: A brushless DC motor control apparatus and method for regulating the speed of a motor at a nominal speed. The apparatus maintains a nominal motor speed without the use of conventional rotor position location devices such as Hall sensors. The current speed of the motor is determined using the back EMF zero-crossing measured only on complete rotor revolutions to mitigate motor dissymmetry errors. A control system compares the current speed to a desired speed and adjusts the total motor current to attain the desired speed. As a result, highly accurate speed control is maintained.

Abstract: An apparatus and method for controlling a motor used for rotating a drill stem is disclosed. Silicon control rectifier based system regulates the power to the motor. A control unit coupled to the SCR regulator and the motor monitors the motor input current, voltage and speed levels. If during operation the motor current exceeds a predetermined value and at the same time the motor voltage or speed falls below a predetermined value, the control unit activates an alarm condition and causes the SCR regulator to controllably ramp down the current supply to the motor and then reduces the motor speed reference.

Abstract: A motor speed controller, for example for accurate linear control of DC motors, includes an error amplifier, such as an integrating error amplifier, for providing a variable controlled voltage to a motor in response to an input to the amplifier, the input comprising a combination of a demand signal representative of a desired speed of the motor and a feedback signal representative of an actual speed of the motor. An electronic switch, such as a transconductance amplifier, has a first input responsive to an electrical signal representative of the actual speed of the motor and a second input responsive to the polarity of the output of the amplifier so as to provide the feedback signal, the value of the feedback signal being dependent on the value of the signal representative of the actual speed of the motor and the polarity of the signal being dependent on the polarity of the output of the amplifier.

Abstract: A method for measuring the rotary speed of a direct-current motor having a rotor and at least a shunt-wound field winding, wherein the field current includes an ac-component caused by mass-inhomogeneities in the rotor, including the steps of: frequency analyzing with a frequency analyzer the ac-component to form a frequency spectrum; selecting with a computing device a part of the frequency spectrum related only to the rotary speed; and determining from the selected part of the frequency spectrum the rotary speed of the motor.

Abstract: A servo circuit for a magnetic disk apparatus includes a target speed generating circuit which generates a target speed in accordance with an amount of movement. A speed signal producing circuit produces a real speed from a position signal from a servo object. A speed error generating circuit controls the speed of the servo object based on an error between the target speed and the real speed. Acceleration and deceleration control are performed to position the servo object at the target position. An acceleration detection circuit detects acceleration and outputs an acceleration-in-progress detection signal for changing a cut-off frequency of the speed error generating circuit between acceleration and deceleration. The servo circuit has a servo loop which supplies a seek current based on an error signal between a target speed and real speed to a voice coil motor and performs speed control on a head carriage.

Abstract: A solid state electronic motor power control circuit for portable paint pumps having a MOSFET power control device and an operational amplifier connected to the MOSFET to selectively operate as a switch driver in a first state and as a linear gain amplifier in a second state. The operational amplifier has a feedback path from the motor to compensate for motor load variations.

Abstract: An apparatus and method for reducing synchronous speed variations in an electric motor having a rotating shaft, comprises a speed transducer for generating a continuous analog speed signal corresponding to the speed of the motor shaft including its synchronous and asynchronous speed variations. A trigger signal is generated each time the shaft rotates through a reference position and is used in conjunction with the speed signal in a fast Fourier transform analyzer to resolve the analog signal into a synchronous time averaged signal which varies with the synchronous speed variations but which eliminates the asynchronous speed variations. An arbitrary function generator is connected to the analyzer for generating an antiwave pattern having a frequency phase and amplitude relative to the waveform from the analyzer. The function generator is connected to a motor controller and superimposes the antiwave pattern onto a control signal internal to the controller which is thereafter applied to the motor.

Abstract: A motor speed control system takes one approach to establish dummy load models having characteristics equivalent to an electric motor to be controlled. One of the dummy load models is established for feedback controlling the electric motor on the basis of the speed of the dummy model. The dummy model is divided into first and second models. The first model is designed to have equivalent characteristics to output a first motor speed representative data. The current to supply to the first model is so adjusted as to reduce a difference between the motor speed representative data and a desired motor speed data to zero. A frequency signal is added to the current applied to the first model and supplied to the electric motor to drive the latter. The second model receives the frequency signal to output a frequency signal dependent second motor speed representative value.

Abstract: An electric motor is disclosed which is of the brushless D.C. type and comprises a generally planar rotor and a generally planar stator. The rotor is a multipolar permanent magnet, and the stator includes a planar coil having a plurality of windings. In order to provide a motor which can supply a high torque at a relatively low speed and a low torque at a high speed, the stator includes a low speed coil which includes a large number of windings of fine wire and a high speed coil which includes a smaller number of windings of coarse wire.

Abstract: The present invention features a system and method for preventing overheating of a motor and/or power amplifier of a material handling vehicle by controlling the performance of the vehicle as a function of motor and/or power amplifier temperature. Temperature sensors are connected to the motor and power amplifier for determining their operating temperatures. A controller is connected to each temperature sensor and to the motor for controlling acceleration of the motor as a function of either or both temperatures, so that both the motor and the power amplifier will not overheat. In controlling acceleration of the motor, the invention provides a mechanism for changing acceleration by discrete steps or continuously according to a performance curve which may be linear or otherwise.

Abstract: There is disclosed a motor speed control system particularly applicable to control sewing machine operation, including an evaluator to compare a preset speed of revolution value and an actual speed of revolution value to output one signal representing a deviation between the two speeds and the other representing a rate of increase or decrease of the actual speed of revolution within a predetermined short interval. In response to these parameter signals, one of the stored fuzzy rules is selectively applied to output an appropriate control signal to change electric power supplied to a motor as needed to adjust the speed of revolution toward the preset revolution with quick responsivity and smooth transition.

Abstract: An improved motor control circuit is disclosed in which energy stored in the motor is transferred back to the power supply rather than being passively dissipated. The sense of a feedback signal is reversed at a summation node by combining the signal with an inverted, amplified reproduction of the signal.

Abstract: An apparatus for controlling the speed of a plurality of DC motors, comprises a device for supplying voltage to one of the plurality of DC motors, first selector for selecting one of the DC motors to be connected to the device for supplying voltage, second selector for selecting a desired speed for the selected DC motor, a device for producing a feedback signal representative of an electrical current drawn by the selected DC motor and a controller for: (i) producing a reference voltage in response to the first and second selectors (ii) producing a load voltage in response to the feedback signal and (iii) outputting a control signal which is the sum of the reference voltage and the load voltage to the device for supplying voltage so that the selected DC motor is operated at the desired speed.

Abstract: A motor rotation speed control circuit fabricated in an LSI, a first counter which, after being reset by each rotation of the motor, begins counting clock pulses. Bit-outputs of the first counter are led out of the LSI package of the LSI, and are selectively connected to external input lead terminals of a plurality of gate circuits, each of which detects when the first counter has counted a number determined by sum of the input bit-outputs. One gate circuit detects a first reference count-number N.sub.a, which is smaller than a probable least count-number corresponding to, for example, a lower limit of tolerance of the motor speed, considering future possible changes of the motor speed. After being reset by a reset signal corresponding to the first refernece number N.sub.a input thereto, a second counter, preset with a second reference count-number N.sub.b, starts to count the clock pulses. The second reference count-number N.sub.b is chosen so that N.sub.a +N.sub.b =N.sub.0, N.sub.

Abstract: It is foreseen to measure the rotational speed (V) of a motor (4) by measuring the electromotive force (e.m.f.) This e.m.f. is calculated as the difference between the terminal voltage (Va) and the voltage drop at a reference resistor (S), through which the armature current flows, then this value is used as a velocity feedback signal for motor regulation. Particularly, the terminal voltage (Va) is cyclically measured at two successive close instants (t1, t2), during which the armature resistance (Ri) and the motor e.m.f. can be considered constant; these terminal voltage values (V.sub.at1, V.sub.at2) are stored, then elaborated to perform the actual armature resistance (Ri) during that interval (t1-t2), then this value is multiplied for the instant current (I). The result is then substracted from the terminal voltage (Va) and only at that time the resulting e.m.f. is used as a velocity feedback signal for the velocity feedback circuit. The apparatus for carrying out this process is also disclosed.

Abstract: Method of measuring the rotary speed of an electromagnetically actuated rotating device having at least one winding carrying a current, which comprises analyzing the frequency of a voltage corresponding to an alternating component of the current, and a device for performing the method.

Abstract: In a power supply apparatus for driving a DC motor of a car cassette player, there is provided a switching regulator circuit for regulating a DC (direct current) input voltage to produce a desired DC output voltage; a motor driving circuit for driving a motor by receiving the DC output voltage of the switching regulator circuit; a sensor element for sensing a speed of the motor to output a sensor signal; a motor speed judging circuit for comprising a sensor signal from the sensor element with a reference signal to produce a judgement signal; and, a control voltage generating circuit for producing a control voltage based upon the judgement signal of the motor speed judgement circuit, whereby the DC output voltage of the switching regulator circuit is controlled in response to the control voltage.

Abstract: An electrical stepper motor system is provided in which a microcomputer controlled driver monitors the real time operating parameters of the stepper motor. The driver is controlled by the microcomputer to keep the real time operating parameters of the motor in a range that is governed by limiting parameters. The limiting parameters are determined by the microcomputer on a moment by moment basis in response to changes in certain conditions occurring within the stepper motor, as well as in the outside operating environment. The microcomputer compares the microcomputer determined safe operating parameters with any user stipulated operating parameters, stored in the storage means of the microcomputer, to determine limiting parameters on a moment by moment basis. An encoder senses the position and velocity of the motor and provides appropriate status signals to enable the driver to compensate for position and velocity errors of the stepper motor.

Abstract: In order to provide a speed control apparatus for a movable equipment having small torque ripples and speed variation, the present invention has a speed control means which comprises a driver for providing a current or a voltage having a magnitude corresponding to the instructed speed, a speed detection circuit for detecting a speed on the basis of a signal from the speed detector and a microcomputer for driving the driver by comparing the speed instruction signal with a speed signal obtained from the speed detection circuit. The microcomputer includes a harmonic wave component detecting means for detecting a harmonic wave component contained in a speed variation mode which is obtained from the speed detection circuit and has a function of making the gain of a speed control system variable by the harmonic wave component detected by the harmonic wave component detecting means.

Abstract: The method consists in mounting the armature of an motor in a bridge circuit and in injecting, at the input of a circuit for amplifying the supply of the bridge receiving the control voltage, an automatic control signal corresponding to the difference between the intensity feedback and the voltage feedback picked up at the terminals of the bridge. Upstream of the amplifier circuit, there is injected an AC voltage with a frequency greater than a cut-off frequency of the motor, the AC voltage generating an AC component of the above-mentioned automatic control signal representing a disequillibrium of the bridge due to a variation of the armature resistance. This AC component is used as a source of a control signal of the gain of an amplifier with adjustable gain of an intensity feedback present at one of the terminals of the bridge.

Abstract: A method of synthesizing load invariant dc drive system comprising positive armature current feedback of exactly specified nature and value of its transfer function. The system transfer function independent of load is realized while stability and dynamics of the system are controlled by additional voltage loop.

Abstract: Method of controlling at least one electric motor on an offset printing machine by inputting a set point for the rotational speed, which comprises forming a set point for the rotational speed by means of a device for controlling the electric motor, and reducing the value of the set point as a function of a measured line voltage when the line voltage is inadequate.

Abstract: An improved induction motor control system utilizes an inverter supplying a variable frequency AC voltage to drive the induction motor, and volt/frequency (V/F) control section controlling the inverter to produce a suitable voltage and frequency in a predetermined relationship therebetween. A power factor detecting section is included to detect a power factor phase angle between the motor current and the inverter output voltage as indicative of an amount of load imposed on the motor. The detected power factor phase angle is compared with a predetermined phase angle which is a frequency dependent angle indicative of a standard load at a given frequency, in order to provide a control output in response to which the V/F control section alters the inverter output voltage out of the predetermined relationship with the frequency for improving motor efficiency. Thus, the detected load (i.e.

Abstract: A pickup driving device for a disk player is provided, wherein the gain of a negative feedback circuit for driving a slider motor is made variable and the gain is changed correspondingly to the operation mode of a disk player, which made it possible to increase the moving speed of a slider motor in a search mode without sacrificing the stability against external disturbances.

Abstract: An electrically propelled vehicle with hydraulic power steering supplied from an electricaly driven pump includes a sensor for sensing any voltage generated in the traction motor of the vehicle, for example, when it is coasting, and after comparing this generated voltage with a reference voltage a sensor for signalling the actuation of the power steering pump when the generated voltage exceeds the reference voltage.

Abstract: A manually operated switch lever moves arm 105 along resistor 113 to generate a "raw" motor speed demand signal which is amplified and inverted by amplifiers 115 and 119 to form a "base line" demand signal.The "raw" demand signal and a motor load signal at the output of amplifier 154 are compared in amplifier 125 to generate an "error" signal. The "error" signal and the "base line" demand signal are summed in amplifier 129 to form a variable reference voltage which is applied to the non-inverting input of comparator 132. The second input to comparator 132 is a triangular shaped wave which is centered about V/2. When the amplitude of the oscillator output wave exceeds the reference voltage, the output of the comparator 132 is low and switch 160 is off. Thus, variations in the D.C. reference voltage at the output of amplifier 129 control the ON-off duty cycle of MOSFET switch 160 to adjust the power applied to motor 106.

Abstract: A method of synthesizing a system which forces a finite value of an impedance to zero comprising positive current feedback of exactly specified nature and value of its transfer function and an internal negative voltage feedback ensuring inherent stability of the system. The converter is used to synthesize electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without position and velocity feedback.

Abstract: A method of synthesizing drive systems, including dc, synchronous and asynchronous ac, and step motor drive systems, of instantaneous response and zero error in both transient and steady state with respect to an input command and of infinite disturbance rejection ratio with respect to a load torque changes, comprising an inner positive current feedback of exactly specified nature and value of its transfer function forcing the motor impedance to zero for load independence, and further comprising control functions in a direct path with respect to both position and velocity feedback loop and in a feedforward path of exactly specified values which, together with the inner positive current feedback loop, provide for the zero-dynamics system transfer function with respect to the command with an associated instantaneous response.

Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive current feedback of a prescribed functionalism and a negative voltage feedback to ensure stability of the system. The prescribed functionalism of the current loop uses arithmetic elements as well as voltage and current measurements to provide for a parameter-free synthesis of the converter whereby the converter operates in the measurement-based mode, the measured variables being the voltage and the current associated with the impedance of interest, without a need to supply values of both resistive and reactive components of the impedance of interest. The converter is used in synthesizing electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without specifying the resistive and the inductive values of the motor impedance.

Abstract: Controlled movement of a motor driven pressure modulator is provided by commanding maximum current to the motor by application of system voltage resulting in the motor current initially rising rapidly to the motor stall current. The motor accelerates at a rate that is a function of the difference between the motor torque and the load torque represented by the load on the modulator. As the motor speed increases, the motor current decreases. When the motor current decreases below the stall current by a predetermined amount representing a predetermined speed of the motor, the motor current is turned off for a wait period that is based upon the time that it took for the motor speed to attain the predetermined speed. Thereafter, maximum motor current is again commanded and the cycle repeated to provide for motor speed control.

Abstract: A motor torque control assembly is provided which can automatically adjust the motor torque so that its reaction torque remains substantially constant, and so that the reaction torque is not changed by changes in motor internal variables, such as bearing drag, current loop tolerances, motor drag, speed change, and temperature change. Such assembly includes a motor subassembly and a feedback subassembly. The motor subassembly has torque input signal means, a summer unit, a compensator unit, a current loop unit, a motor unit, and a torque output means. The feedback subassembly has torque output sensing means connected to the torque output means for measuring the reaction torque value and connected to the summer unit for measuring the difference of the reaction torque value from a motor torque value of the torque input signal means.

Abstract: An apparatus for detecting an over-velocity error condition of a head actuator driven by a voice coil motor in a hard disk drive system includes an integrator for providing an integrated value of the current flowing through the voice coil motor and a detector for detecting when the integrated value exceeds a threshold value. In response to this detection, the supply of current through the voice coil motor is interrupted. To prevent false detections, the integrator is inhibited until the motor current reaches a level indicative of a track access operation.

Abstract: A motor control circuit measures the motor voltage to determine actual motor speed. This speed voltage is the sum of the back emf and armature loses. The control circuit receives a reference voltage proportional to the desired motor speed and a further signal voltage indicative of the motor armature losses. These three voltages are combined to provide a first error signal representing the difference between the reference voltage and the motor back emf. This error signal is substractively combined with a signal representative of the motor power to produce a control signal for a modulator circuit which in turn controls a semiconductor switch in series with the motor.

Abstract: A rod antenna control system for automobiles wherein electric current is supplied continuously to a motor which pushes up an antenna motor when a current below a predetermined value is flowing to the motor, and the current is supplied intermittently to the motor when a current above a predetermined value flows to the motor, and whether or not the electric current is over or below the predetermined value is determined by integrating the motor current for certain period of time and comparing such integrated value to the predetermined value.