Abstract: In a control method of a dual three-phase permanent magnet synchronous motor by alternately performing sampling and control procedures, sampling instants, vector loading instants, and reference value tracking instants of two sets of windings alternate in two halves of a sampling period, and the equivalent sampling frequency of the motor drive system is doubled and the digital delay and the predictive horizon are halved without changing the sampling frequency of a single set of three-phase windings. In addition, by a two-layer MPC strategy, a deficient-rank problem is settled that the controlled dimensionality of the system is reduced to two dimensions but the motor control objective is still four dimensions caused by the method with controlling a dual three-phase permanent magnet synchronous motor by alternately performing sampling and control procedures.

Abstract: A control method of a cleaning robot, where the cleaning robot includes a top part, a bottom part, and a vacuumizing assembly for air extraction, the bottom part of the cleaning robot is provided with at least two rows of driving wheels being respectively provided on both sides of the bottom part of the cleaning robot, and the cleaning robot includes a cleaning mode for cleaning the driving wheel; the method including: performing a cleaning mode of the cleaning robot; and after the cleaning robot performs the cleaning mode, turning off the vacuumizing assembly or maintaining the vacuumizing assembly in a turned off state, and starting and rotating at least one row of the driving wheels.

Abstract: The present disclosure discloses a method for reminding a replacement of a filter of a vacuum cleaner, including: obtaining a rotating speed difference of a motor within a set time interval; comparing, according to a working parameter of the vacuum cleaner, the rotating speed difference with a preset rotating speed difference threshold, to obtain a comparison result; and determining whether to remind a user to replace the filter according to the comparison result. With the method provided by the present disclosure, the vacuum cleaner may timely and automatically remind the user to replace the filter during the use of the vacuum cleaner, thereby reducing power loss, maintaining the normal use of the vacuum cleaner, and prolonging the service life of the motor.

Abstract: A method carries out a switchover of a first switch or at least one second switch for equipment. The method includes receiving, by a controller, a switching signal; selecting, by the controller, the first switch or at least the second switch for switchover on the basis of the switching signal; querying, by the controller, at least one parameter of the first switch or the at least second switch; checking a locking condition on the basis of the at least one queried parameter for the first switch or a locking condition for the at least second switch; and carrying out the switchover by the selected first switch or the at least second switch based upon the corresponding locking condition being met.

Abstract: A method for controlling a stepper motor includes calculating a duty cycle of a current provided to the stepper motor and comparing a difference, between the calculated duty cycle and a base duty cycle of current provided to the stepper motor under a base load condition, to a reference duty cycle value. The method also includes adjusting a peak current level of the current provided to the stepper motor responsive to the comparison.

Abstract: An electric motor speed controller includes a processor connected to the following terminals, a base voltage terminal receiving a base voltage, a first voltage terminal provided with a constant voltage, and a second voltage terminal receiving a first motor coil voltage from the processor, and a third voltage terminal receiving a second motor coil voltage from the processor. The processor provides a first control period having the second motor coil voltage be zero and a second control period having the first motor coil voltage be zero. The processor determines the motor speed by controlling a difference between a first time period in the first control period and a second time period in the second control period. The first time period corresponds to a first output voltage increase and the second time period corresponds to a second output voltage increase.

Abstract: A method for evaluating a vibration behavior of an electric motor includes: determining a vibration value of the electric motor by measuring an acceleration and/or speed of vibrations of the electric motor using a vibration sensor of the electric motor, wherein vibrations are measured in at least one direction, said vibration value representing each of the at least direction measured, determining a current rotational speed (n) of the electric motor, comparing said vibration value with a reference value for the current rotational speed, and determining an evaluation measure for evaluating the vibration behavior of the electric motor based on the comparison of the vibration value with the reference value. Furthermore, a corresponding electric motor and a system consisting of the electric motor and a test system is disclosed with which the vibration behavior of the electric motor can be calibrated and reference values can be generated.

Abstract: One or more multiphase power converters are connected to a power supply via a high potential line and a low potential line, convert DC power of the power supply into multiphase alternate current power by operations of inverter switching elements, and apply a voltage to each of phase windings of the multiphase winding set. A DC rotating machine switch are made up of two or more legs, each of which is made up of switches on a high potential side and a low potential side connected in series via a DC motor terminal connected to a second terminal that is an end of the DC rotating machine. The DC rotating machine switch makes a voltage of the DC motor terminal variable by switching. A control unit controls operations of the inverter switching elements and the DC rotating machine switch.

Abstract: Provided are a robot cleaner using an artificial intelligence (AI) and/or machine learning algorithm in a 5G environment connected for the Internet of Things and a method for determining a cleaning path of a robot cleaner. The method for determining a cleaning path includes detecting an obstacle, identifying a type of the obstacle based on the image signal, generating a cleaning map including information on the identified obstacle, providing the cleaning map to a user terminal, receiving an input of a cleaning pattern for an area of the obstacle from the user terminal, and determining a cleaning path including the cleaning pattern for the area of the obstacle.

Abstract: A motor controller configured to reduce the motor noise by detecting the zero point of the motor current is disclosed. The motor controller comprises a switch circuit, a pre-driver, a phase detecting unit, a control unit, a comparator, a first resistor, and a second resistor. The switch circuit is an H-bridge circuit. The switch circuit includes a first upper-side switch, a second upper-side switch, a first lower-side switch, and a second lower-side switch. When the motor controller performs the last pulse width modulation driving with respect to the first lower-side switch before phase switching, the second upper-side switch is turned off and the first lower-side switch is kept turning on, so as to facilitate the detection of the zero point of the motor current.

Abstract: An autonomous floor cleaner can include a housing, a drive system for autonomously moving the housing over the surface to be cleaned, a controller for controlling the operation of the autonomous floor cleaner, a tank adapted to hold liquid, and a carry handle joined with the tank and/or the housing. The carry handle is movable between a stowed position and a carry position. The carry handle can include one or more capturing assemblies such that the carry handle can be selectively rotated between different orientations allowing for one or more of: locking/securing the tank to the housing, activating/deactivating the floor cleaner based on handle position; carrying the entire floor cleaner; ejecting the tank from the housing; carrying the tank separately; and emptying the tank.

Abstract: In order to reduce deviation of correction amount when calculating a magnetic pole position correction amount of a permanent magnet type rotating electrical machine, and perform magnetic pole position correction with high accuracy, in state where the permanent magnet type rotating electrical machine is rotated, a d-axis current command value and a q-axis current command value in dg vector control are kept substantially zero, an actual d-axis voltage and an actual q-axis voltage are calculated from a midpoint potential detected from a midpoint potential detection unit, a magnetic pole position correction amount is calculated based on a predetermined arithmetic expression from the actual d-axis voltage and the actual q-axis voltage, and magnetic pole position origin correction is performed based on the magnetic pole position correction amount.

Abstract: A medical observation device includes: an imaging device; a support unit that supports the image-capturing unit and includes arms and joints rotatably connecting the arms; a motor that applies power to at least one of the joints, and rotates two of the arms connected at the joint relative to each other; a gear mechanism that includes two intermeshing gears and is disposed in a power transmission path from the motor to the at least one joint; an operation receiver that receives a user operation; and a controller that performs first control for causing the motor to rotate in accordance with the user operation received by the operation receiver and performs second control after the first control is completed and rotation of the motor is stopped.

Abstract: A method and a system for acquiring a rotor position of a rotary transformer are provided. The system includes: a rotary transformer decoder, a low pass filter and a microprocessor, which includes a synchronous demodulation module and a calculation module. The rotary transformer decoder outputs an excitation signal and acquires first position information of the motor rotor. The calculation module performs calculation to acquire second position information of the motor rotor. The rotary transformer decoder and software decoding are integrated to acquire two rotor positions, and the two rotor positions are compared. In a case that a preset determining condition is met, one of the rotor positions is used for motor control, and the other is used as redundant data for backup, thereby improving the reliability of the acquired rotor position.

Abstract: A harmonic Hall voltage analysis method is provided to analyze a damping-like effective field ?HDL and a field-like effective field ?HFL with respect to polar angles of all magnetizations and a ratio R of an anomalous Hall effect resistance RAHE to a wide plane Hall resistance RPHE (R=RAHE/RPHE).

Abstract: A method according to an exemplary aspect of the present disclosure includes, among other things, detecting a position, including a polarity, of a rotor to detect incorrect rotor position offset of an electric machine without generating torque or motion within the electric machine.

Abstract: A driving circuit for driving a capactive load includes: a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal; a gate driver that generates an amplification control signal, based on the modulated signal; a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal, based on the amplification control signal; a low pass filter that generates a drive signal by demodulating the amplified and modulated signal; a piezoelectric element that is displaced by the drive signal which is applied; a first power supply unit that applies a signal to a terminal, other than a terminal to which the drive signal is applied; and the first power supply unit are connected to a common ground terminal.

Abstract: A fan driving circuit includes a processing module providing a fan phase signal and a speed signal providing module electrically connected to the processing module and including a first switch having a first terminal, a second terminal receiving the fan phase signal and a third terminal electrically connected to a ground voltage, a second switch having a first terminal electrically connected to a speed signal providing terminal of the fan driving circuit and a first terminal of a first impedance, a second terminal electrically connected to a second terminal of the first impedance and a terminal of a diode, and a third terminal electrically connected to the first terminal of the first switch, and a third switch having a terminal electrically connected to a bias voltage.

Abstract: A system is provided for controlling a line speed of a conveyor belt of a conveyor system during product changeovers in a wallboard production line. A central control module controls operation of a position sensor and a database. The position sensor is located on top of a conveyor table for providing positional information of a slurry head formed in front of a forming plate of the conveyor system. A position detection module receives a position signal from the position sensor, and determines whether the slurry head is located within a predetermined distance relative to the position sensor based on the position signal. A speed adjustment module regulates the line speed of the conveyor belt based on the position signal.

Abstract: A motor control circuit for controlling an electric motor may include at least one switching device configured to receive, from a pulse modulation device, a pulse modulated signal and output, based on the pulse modulated signal and to the electric motor, a current. In some examples, a frequency of the pulse modulated signal is below a threshold frequency. The motor control circuit may also include a transient detection circuit configured to detect a current transient, and responsive to detecting the current transient, output a pulse. The motor control circuit may further include a pulse counter configured to update, based on the pulse, a value indicative of a position of a rotor of the electric motor; and output the value indicative of the position of the rotor.

Abstract: The brushless motor driving circuit includes a peak hold circuit that outputs a second voltage obtained by holding a peak of a first voltage that is based on a detected voltage responsive to a voltage drop in the detecting resistor. The brushless motor driving circuit includes a filter circuit that outputs a third voltage, which is a direct-current component of the second voltage. The brushless motor driving circuit includes a differential voltage detecting circuit that outputs a first differential voltage between the second voltage and the third voltage. The brushless motor driving circuit includes a computing circuit that calculates a second differential voltage between the analog voltage and a fourth voltage responsive to the first differential voltage, and outputs a speed control signal responsive to the second differential voltage.

Abstract: The invention relates to a method for operating a brushless electric motor, the windings of which are controlled by an inverter using six switches, wherein the inverter comprises three outputs, which are associated with the windings of the electric motor, and wherein a respective power semiconductor switch is arranged between the output of the inverter and the windings, and wherein a detection unit for detecting defective switches, a unit for measuring the voltage at the outputs of the inverter, and a microcontroller for controlling switches are provided. The invention further relates to a device operating a brushless electric motor. In order not to damage the power semiconductor switches, according to the invention of the inverter is switched off by the microcontroller after a defective switch has been detected, such that no additional power is introduced in the windings (U, V, W) of the electric motor and the power semiconductor switches are opened in a predetermined motor angle position (?U, ?v, ?w).

Abstract: In an electronic commutation method in direct current electric motors which are controlled by pulse width modulation of the energization which takes place periodically with positive and negative current values and intermediate energization pauses, the counter-induction voltage is measured, wherein the zero crossing of the counter-induction voltage is determined by means of the point of intersection of the envelope to the counter-induction voltage with the zero line. The pulse width modulation of the energization is changed if the zero crossing is covered by positive or negative current values of the energization.

Abstract: A motor system includes a motor including two Hall sensors configured to output binary values, and a controller configured to control the motor. The two Hall sensors are placed 120 or 60 electrical degrees apart. The controller is operable to monitor output signals of the two Hall sensors and to determine a third Hall sensor output binary value. The controller is operable to fulfill the commanded requirements to operate in a servo system, by controlling commutation of a drive current into the motor, and by keeping track of the motor rotor position based on the third generated signal and the outputs of the two Hall sensors.

Abstract: The present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage, and a current control gain adjusting step of calculating a current control gain based on frequency characteristics of the applied voltage and the motor current. In this manner, a stable current control gain having a high current response can be adjusted within a short period of time.

Abstract: The present invention includes a voltage applying step of applying an applied voltage including a DC component and a plurality of frequency components to a PM motor, a motor current detecting step of detecting a motor current flowing depending on the applied voltage, and a current control gain adjusting step of calculating a current control gain based on frequency characteristics of the applied voltage and the motor current. In this manner, a stable current control gain having a high current response can be adjusted within a short period of time.

Abstract: An estimation section estimates a time period required for a norm of a difference vector between a current flowing to a motor/generator and a command current to attain a threshold level r in each switching mode provisionally set by a mode setting section. A mode determination section determines the switching mode of the longest required time period to be a final switching mode. A drive section controls an inverter to operate in the switching mode determined by the mode switching section.

Abstract: Techniques and apparatus for limiting the current through a motor, such as a motor for rotating a rotatable element of a hard drive. The current can be limited based on a threshold. A first threshold value can be set for a first time period. A second threshold value can be set for a second time period in which the current through the motor rises. The second threshold value is lower than the first threshold value. A spike in the supply current upon accelerating the rotatable element of the motor can thereby be reduced or eliminated.

Abstract: In a control unit that controls a control amount of a rotary device by controlling on and off states of switching elements of a power converting circuit, a relative rate predicting section temporally sets operation states of the power converting circuit and predicts a relative rate of a control amount according to each of the temporally set operation states relative to a command value thereof. Each of the operation states is indicated by a voltage vector defined by the on and off states of the switching elements. A determining section determines an operation state of the power converting circuit based on the relative rate predicted by the relative rate predicting section. An operating section operates the power converting circuit to the operation state determined by the determining section.

Abstract: An air moving appliance comprising an electric motor coupled to a fan, a control system for controlling the motor, the control system including monitoring means configured to monitor a motor load parameter; memory means configured to store a predetermined reference motor load parameter value; compensating means that determines a compensated reference motor load parameter value based on the predetermined reference motor load parameter value and a set of ambient environment input conditions; comparison means configured to compare the motor load parameter and the compensated reference motor load parameter value and trigger an operational event based on the result of the comparison. The invention also relates to a method of controlling an air moving appliance.

Abstract: A method is disclosed for operating a synchronous machine by way of a three-phase AC power controller, which is connected to a three-phase network. The embodiment of the method includes determining the phase difference between the magnet-wheel voltage of the synchronous machine and the network voltage of the three-phase network; determining the rotational speed of the rotor of the synchronous machine; determining the phase position of the three-phase network; determining a decision characteristic number on the basis of a stored data table calculated in advance, which data table associates a decision characteristic number with value triples of phase difference, phase position, and rotational speed; and determining at least one switching time point on the basis of the decision characteristic number.

Abstract: An estimation section calculates estimated currents corresponding to switching modes, which are provisionally set by a mode setting section. A mode determination section determines one of modes, which has a smallest difference between the estimated currents and command currents, to be a final switching mode. A drive section drives an inverter in the switching mode determined by the determination section. The estimation section uses transient-state inductances as coefficients of time differentiation of currents in voltage equations used for estimation of the estimated currents. These are different from steady-state inductances, which are coefficients of multiplication of currents and electric angular velocity.

Abstract: According to one embodiment, a controller of a motor includes a driving signal output module, a position detector, a determiner, and an over current detector. The driving signal output module is configured to generate a driving signal for generating a driving current of a motor, a duty ratio of the driving signal being depending on an over current detection signal. The position detector is configured to generate a position detection signal for determining an operating status of the motor by comparing an induction voltage generated by a rotation of a rotor of the motor by the driving current with a predetermined reference voltage. The determiner is configured to determine whether the motor is in a starting state where a rotating frequency of the rotor is smaller than a predetermined value or in a steady state where the rotating frequency of the rotor is equal to or higher than the predetermined value based on the position detection signal.

Abstract: In a norm setting section, a norm of an output voltage vector of an inverter is set based on a required torque and an electrical angle speed. In a phase setting section, a phase is set as controlled variables for performing a feedback control of an estimated torque to the required torque. In an operation signal generating section, operation signals are generated based on the norm set by the norm setting section and the phase set by the phase setting section, and the signals are outputted to the inverter. Based on the value of the phase, existence of abnormalities of a permanent magnet of a motor-generator is determined.

Abstract: A BEMF detection circuit generates a rotation detection signal indicating a comparison result between electromotive force voltages VU through VW which occur at a terminal of respective multiple coils and an intermediate-point voltage VCOM. A rotor position detection circuit generates a rotor position detection signal indicating a stopped rotor position An internal start-up synchronization signal generating unit generates a predetermined-frequency forced synchronization signal. Upon receiving a fan motor start-up instruction, a driving signal synthesizing circuit generates a driving control signal based upon the rotor position detection signal. Thus, (1) when back electromotive force voltage occurs, a sensorless driving operation is started based upon the rotation detection signal; (2) when it does not occur, the driving control signal is generated based upon the forced synchronization signal. Subsequently, when it occurs, the sensorless driving operation is started based upon the rotation detection signal.

Abstract: A method according to an example of the present invention is a servo control method to be applied to a feed drive mechanism configured to drive an object to be driven by using a plurality of motors, in which velocity control of the object to be driven is carried out by using a signal obtained by mixing velocity feedback signals of the motors with each other, and a torque instruction obtained by the velocity control is used for drive of all the motors. By this example, there is provided a servo control system capable of preventing a phenomenon in which a transfer function changes depending on the position of the object to be driven, and the phase abruptly lags to make the operation unstable, thereby making it difficult to increase the gain, from occurring.

Abstract: A method and system for controlling a motor is provided. In particular, various embodiments of the present disclosure describe a method and system for controlling a spindle motor in a hard disk drive (HDD) A method of controlling a motor is provided, the motor including a 3-phase synchronous motor with three terminals of an electromagnetic winding configuration. The method includes providing an input voltage between two of the terminals and measures a resultant silent terminal voltage at the third terminal, which is thereafter used in determining a rotor position. A corresponding system for controlling a motor is further provided.

Abstract: A voltage determination device includes a reference voltage generation circuit; a determination target voltage line; a first voltage line; a second voltage line; and a switching circuit disposed between the first voltage line and the second voltage line. The switching circuit is provided for performing a switching operation according to a level of the determination target voltage. The voltage determination device includes a determining circuit for determining the level of the determination target voltage, and a control unit is provided for controlling a level of an electric current flowing between the first voltage line and the second voltage line. The control unit controls a resistivity between the switching circuit and the second voltage line so that the level of the electric current is maintained at a specific level when the determining circuit determines the level of the determination target voltage.

Abstract: An electronic device and a method for controlling fan speed of the electronic device include setting a speed range corresponding to a variety of pulse-width modulation (PWM) duty cycles of the fan, and setting a speed variation value of the fan. The method further includes reading the PWM duty cycle and detecting an actual speed of the fan, and adjusting the PWM duty cycle in the PWM duty cycle instruction according to the speed variation value.

Abstract: A motor drive circuit includes: a drive circuit configured to drive a motor whose coil current decreases with increase in counter electromotive voltage of a motor coil; a detection circuit configured to detect whether or not a current value of the coil current is greater than a predetermined value; a first control circuit configured to control the drive circuit so that the current value of the coil current becomes smaller than or equal to the predetermined value, when it is detected that the current value of the coil current is greater than the predetermined value; and a second control circuit configured to control the first control circuit so that the first control circuit does not control the drive circuit based on a detection result of the detection circuit until a predetermined time has elapsed from a start of supply of the coil current.

Abstract: A motor drive circuit includes a positive and a negative supply rail for connection to a battery (104), a motor drive circuit including a plurality of motor drive subcircuits which each selectively permit current to flow into or out of a respective phase of a multi-phase motor (101) in response to control signals from a motor control circuit, and a switching means including at least one switch which is in series with a respective phase of the motor which is normally closed to permit the flow of current to and from the subcircuit to the respective motor phase. A fault signal detecting means (160) detects at least one fault condition and, in the event of a fault condition being detected, causes the at least one switch to open. A snubber circuit (150) is associated with the motor and is arranged so that following the opening of the switch, energy stored in the motor windings is diverted away from the switching means through the snubber circuit to the battery.

Abstract: A controller for a brushless motor that includes a processor, a first timer, a second timer, a compare register, a comparator, an input, and one or more outputs. The processor starts the first timer in response to a signal at the input. The first timer then generates an interrupt after a first period. In response to the interrupt, the processor generates a first control signal at the outputs. The processor also loads the compare register and starts the second timer in response to either the input signal or the interrupt. The comparator then generates a second control signal at the outputs when the second timer and the compare register correspond. Additionally, a motor system that includes the controller.

Abstract: A device for the change of the driving mode of an electromagnetic load from a first operating mode with pulse width modulation to a second operating mode that is linear by means of switching circuits. During a first operating mode, each of two outputs has a voltage value ranging from a first reference voltage to a second reference voltage. The device adapted to synchronize a change command signal from a first operating mode to a second operating mode of the electromagnetic load with the signal representative of the flow of current circulating within the load at substantially its average value and adapted to generate a first command signal in response to the synchronization.

Abstract: A motor drive device includes a drive controller for generating drive signal “trq”, a limiter for limiting a value of drive signal “trq” within a range, a limit value generator for generating limit value “lmt”, and a drive output section for generating an energizing signal in response to an output signal from the limiter. The limit value generator generates a comparison signal by adding offset value “ofs” to drive signal “trq” and updates limit value “lmt” based on a size relation between a value (trq+ofs) of the comparison signal and limit value “lmt”.

Abstract: A Halbach array is radially disposed in an environment optimized for efficiency and controlled for efficient generation and use of power in order to generate, establish, and maintain a desired level of rotational energy with enhanced efficiency and in order to make the most efficient use of electromotive forces and magnetic fields which are either intentionally created for the operation of the apparatus or which result from the operation of the apparatus.

Abstract: A control apparatus controls an inverter (electric power converter circuit) which is connected for selectively applying a plurality of voltage levels to each phase of a polyphase rotary machine. In each of successive control periods, the apparatus determines the inverter operation state (combination of respective voltage levels applied to the phases) to be set for the succeeding control period, by performing prediction calculations based on a model of the rotary machine, for each of a plurality of candidates for the next operation state, to select an optimum candidate. The candidates are restricted to those operation states whereby the voltage level of no more than one of the phases will be changed, at changeover to the operation state of the next control period.

Abstract: A brushless motor device switches between a 120-degree energization method and a 180-degree energization method of advancing an electrical angle by 30 degrees to drive a brushless motor 1 according to the result of a comparison between the rotational speed of the brushless motor 1 and a predetermined threshold.

Abstract: A LIN receiver includes a voltage divider that divides an input voltage and outputs the divided voltage, and a peak hold circuit that outputs a peak voltage of the input voltage. The LIN receiver is configured to generate a threshold voltage to be used for determining a voltage signal of a communication bus. The threshold voltage is generated from a voltage signal of the communication bus such that the peak value of the voltage signal (i.e., equivalent to a battery voltage) is held by the peak hold circuit and divided by the voltage divider. Although the communication bus is connected to an on-vehicle battery of which voltage varies with time, by using the voltage signal of the communication bus, a 5V system ECU can generate a threshold voltage which varies responding to the variation of the battery voltage. Hence, the voltage signal can be determined correctly as either high or low level.

Abstract: The invention relates to a circuit unit for driving an electronically commutated fan motor with a power stage for driving windings of the fan motor and with a control stage for driving the power stage. The circuit unit is distinguished in that an operating voltage of the control stage is separated from an operating voltage of the power stage by a diode and in that an arrangement is provided for smoothing the operating voltage of the control stage.

Abstract: Method for control of synchronous electrical motors with application for stepper and Brush-Less Direct Current motors for which there is an explicit relation between the active electrical power supplied to the motor and the mechanical power that the motor delivers to the load. The active electrical power Pel consumed by the motor is measured and according to FIG. 3 the mechanical power Pmech and the maximum available mechanical power Pmech max are determined. The ratio between Pmech and Pmech max is calculated and is compared to the set value of the same ratio. If it is greater than the set one either the operating currents are increased either the operating speed is decreased or both operations are executed. But if it is smaller—either the operating currents are decreased either the operating speed is increased or both operations are executed.