Abstract: A method for controlling a wheel speed of a locomotive includes determining an estimated wheel speed (52) for a desired wheel set of a locomotive responsive to a locomotive operating parameter indicative of an actual wheel speed of the desired wheel set. The method also includes generating a first adjustment parameter (e.g., 46) based on an operating condition of the locomotive, and then applying the first adjustment parameter to the estimated wheel speed for generating a first adjusted estimated wheel speed signal (54) used as a first input for controlling a wheel speed of at least one of the desired wheel set and the other wheel sets of the locomotive.

Abstract: A trigger switch performs speed control of a motor according to a pull-in amount of a trigger. A wiring path for lead wires connects the trigger switch and an auxiliary device. The wiring path is formed in an insulating wall. The insulating wall isolates a pair of power supply terminals, each connected to a power supply, from each other.

Abstract: An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.

Abstract: An image sensing apparatus, which has a constant-voltage driven stepping motor, comprises a PWM waveform generation part that generates pulse signals to be applied to switching devices; and a PWM waveform determination section that determines a PWM waveform to be generated by the PWM waveform generation section. The PWM waveform determination section determines, in accordance with the determined rotation speed value and output torque value of the stepping motor, a duty ratio range that is a range extending from the minimum to the maximum of the duty ratio of the pulse signals. It is designed that the higher the rotational speed value is, the wider the duty ratio width is.

Abstract: An airflow detection apparatus configured to detect airflow of a fan includes a first transistor, an amplifier, an A/D converter, a microprocessor, an indicating circuit, and a stabilizing circuit configured for supplying a stable current to the first transistor. The base and the collector of the first transistor are connected to a power supply. The emitter of the first transistor is connected to the amplifier and the stabilizing circuit. The amplifier receives a voltage signal from between the base and the emitter of the first transistor. The voltage signal is converted into a digital signal by the A/D converter. The microprocessor processes the digital signal and output an indicating signal to the indicating circuit to indicate airflow status of the fan.

Abstract: The rotating speed of an output shaft of a door opening and closing motor actuating a sliding door is monitored, and whether a fluctuation value of the rotating speed is equal to or more than a first determination threshold value is determined (step S310). A second determination threshold value having a pinching detecting sensitivity that is higher than the first determination threshold value is set. When it is determined that the shift lever of the transmission is in a P position, or a foot brake is operating, or a parking brake is operating, whether the fluctuation value of the rotating speed is equal to or more than the second determination threshold value is determined (step S360). If the fluctuation value of the rotating speed is equal to or more than each of the determination threshold values, the sliding door is actuated in an opening direction (step S320).

Abstract: An HVAC system includes a variable speed electric motor driven fan for circulating air to an enclosed space through an indoor unit for providing heating or cooling effect to air circulated through the indoor unit. A controller with user or system installer actuatable switches includes a programmable microcontroller providing a pulse width modulated (PWM) signal to a motor control unit to select a predetermined air flowrate less than full air flowrate during system startup and shutdown. User input parameters include selected percentages of full air flowrate to satisfy requirements for reduced noise level, lower humidity and for improved sensible heating of air being circulated, the latter being effective particularly for heat pump applications. Selection of pre-run, short run and shutdown cycles may be provided.

Abstract: A system for controlling a roller shade having a roller tube windingly receiving a shade fabric varies roller tube rotational speed for constant linear shade speed. The desired linear shade speed, roller tube diameter and shade fabric thickness and length are stored in a memory for use by a microprocessor. Preferably, the roller tube rotational speed is varied by the microprocessor depending on shade position determined by signals from Hall effect sensors. The microprocessor maintains a counter number that is increased or decreased depending on direction of rotation. Based on the counter number, the microprocessor determines shade position and a corrected rotational speed for the desired linear shade speed. Preferably, the microprocessor controls roller tube rotational speed using a pulse width modulated signal. The system may be used to control first and second roller shades having roller tubes of differing diameters or shade fabrics of varying thicknesses.

Abstract: The present invention provides a fan that has a fan motor and two signal lines including a number-of-rotations switching control signal line and a rotational state outputting signal line, makes the fan motor rotate at a number of rotations determined by a number-of-rotations switching control signal input via the number-of-rotations switching control signal line, outputs the rotational state of the fan motor via the rotational state outputting signal line, and can provide notification of detail data without increasing the number of signal lines. The fan retains data in the data storage section in a non-volatile manner and outputs the data via the conventionally existing rotational state outputting signal line.

Abstract: A driving apparatus and a driving method for a single phase motor utilizes a driving transistor unit, and an auxiliary driving transistor unit to provide two driving currents with the same direction as the single phase coil. Next, a control unit is used to control the conducting and shutting down of the driving transistor unit and the auxiliary driving transistor unit according to the location of the rotating device of the single phase motor. Thereby, the driving current on the single phase coil recirculates to reduce the vibration and noise of the single phase motor, and prevent the problem of the single phase motor not turning on.

Abstract: A fan control system includes a power source, a switch control circuit, a switch control signal delivering unit and a fan circuit module. The power source outputs a nominal power, the switch control circuit electrically connects to the power source, the switch control signal delivering unit electrically connects to the switch control circuit and can send a power control signal to the switch control circuit, and the fan circuit module electrically connects to the switch control circuits. In an initial operation state, the nominal power output from the power source can be reduced to a control power sending to the fan circuit module via the switch control circuit to drive at least one fan within the fan circuit module, and then the power control signal controls the control power after the switch control signal delivering unit sends the power control signal to the switch control circuit.

Abstract: A control device 50 of an electric rotary excavator generates a rotation speed coefficient in accordance with a setting condition of a fuel dial 13 and a selection condition of a mode selection switch 14 and changes a value of a target speed command value based on the rotation speed coefficient to change a rotation speed of a rotary body 4. Accordingly, when the engine speed becomes low through operation of the fuel dial 13 or the mode selection switch 14, the rotation speed of the rotary body 4 can be decreased accordingly, while when the engine speed becomes high, the rotation speed can be increased accordingly. Therefore, the operation feeling substantially similar to a conventional arrangement for hydraulically rotating the rotary body 4 can be obtained, so that the operator is not confused when the operator shifts excavators from the conventional hydraulic excavator to the electric rotary excavator.

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: An apparatus for controlling rotational speed of a fan includes a sensor module, a single chip microcomputer (SCM) module, and a driving module. The sensor module collects rotational speed signals of a fan, and converts the rotational speed signals to voltage signals. The SCM module receives the voltage signals from the sensor module and compares the voltage signals with a predetermined rotational speed value stored in the SCM module, and outputs a control signal according to the comparison. The driving module receives the control signal from the SCM module, and outputs a pulse width modulation (PWM) signal to control the rotational speed of the fan.

Abstract: A fan speed control device includes a management selection module, a first and a second buffers, a resistor, a transistor, and a switch. Depending upon whether a motherboard supports a system of a baseboard management control or not, the fan speed control device selectively uses an indicative signal of a serial input and output interface or an indicative signal of the baseboard management control to indicate a power-on status. At the power-on moment, the fan speed control device controls the fan to operate at its minimum speed, so that a system crash due to a power output shortage of a power supply can be avoided. As the system enters stable operation, the fan speed is controlled by a pulse width modulation signal.

Abstract: Embodiments of the invention provide a disk device and a method of controlling the device which is capable of suppressing peak current, even for serial communication, that is required when initiating rotation of a spindle motor down to a level equivalent to that of parallel communication, without prolonging elapsed time before reaching the steady rotation speed. In one embodiment, an HDD includes a serial communication circuit which executes serial communication with a host, an SPM which rotates a disk, an HDC/MPU which controls the SPM and the serial communication circuit. The HDC/MPU, after shutting down the serial communication circuit once, starts up the serial communication circuit again when rotation speed of the SPM reached the specified standard value, and establishes serial communication with the host by means of the serial communication circuit.

Abstract: An escape sequence coded in power commands from a system controller, such as a BMC, to a cooling fan controller directs the cooling fan to send identification information coded in tachometer readings to the system controller for use by an information handling system. Electronic confirmation of the cooling fan identification ensures compatibility of the information handling system and cooling fan at initial manufacture or subsequent repair. Communication of information over existing power and tachometer wires supports the electronic confirmation without adding additional communication lines. Further, once a communication link is established between an information handling system controller and a cooling fan, other functions are enabled, such as a reflash of the cooling fan controller firmware.

Abstract: A system includes a current control module that supplies current to a voice coil motor during a first period to rotate an actuator arm in a first rotational direction, that discharges the current from the voice coil motor after the first period, and that generates a control signal a predetermined period after the current is discharged. A back electromagnetic force (bemf) module generates a bemf signal in response to the control signal. A speed control module determines a speed of the actuator arm based on the bemf signal.

Abstract: A start-up circuit which decreases a start-up current and stabilizes running of a DC fan. The start-up circuit includes a digital-analog converter for convert a digital control signal from a control chip to an analog control signal, a voltage sampling device connected to an output terminal of the digital-analog converter, a comparator, a switching device for controlling start-up of the DC fan, and a feedback device adjusting current passing through the switching device. The comparator includes two input terminals and an output terminal. One input terminal is connected to an output terminal of the voltage sampling device. The switching device is connected to the output terminal of the comparator. An output signal of the switching device is inputted to the other input terminal of the comparator via the feedback device.

Abstract: A magnetizing motor having a permanent magnet body covering an outer circumferential surface of a rotor body, includes a speed detecting unit that detects a speed of the magnetizing motor; and a controlling unit that compares the speed detected by the speed detecting unit with a reference speed, and outputs a magnetizing control signal based on the result of the comparison.

Abstract: An electric fan device includes a motor which drives an electric fan for a vehicle, a control switch which controls a motor current supplied to the motor, and a control unit which controls an on/off operation of the control switch with pulse-width modulation. The control unit outputs a PWM pulse having a main PWM pulse and a vibration reducing pulse within one cycle to the control switch.

Abstract: The present invention employed a motor control device including: current sensors which detect currents in each phase of a three-phase motor; a coordinate conversion device which computes a d-axis actual current and a q-axis actual current in dq-coordinates from phase currents of three phases based on detection values of the current sensors; a voltage instruction computation device which computes a d-axis voltage instruction and a q-axis voltage instruction based on a deviation between a d-axis current instruction and the d-axis actual current and on a deviation between a q-axis current instruction and the q-axis actual current; a target phase current computation device which computes target phase currents for each phase from the d-axis current instruction and the q-axis current instruction; and a current difference computation device which computes, for each phase, a current difference between the phase current and the target phase current.

Abstract: The apparatus for closing a closure of a vehicle comprises a closure driver for moving the closure and an electronic control unit electrically coupled to the closure driver. The electronic control unit is configured to determine if predetermined speed criteria is satisfied and to operate the closure driver so as to close the closure at a first closing speed if the predetermined speed criteria is satisfied or at a second closing speed if the predetermined speed criteria is not satisfied. The second closing speed is less than the first closing speed regardless of the position of the closure so that a squeezing force applied by the closure to an obstruction remains less than a predetermined squeezing force. An associated method is disclosed.

Abstract: Information indicative of the placement of spindle motor components may be obtained and used to provide a correction to one or more BEMF-derived attributes used to control the spindle speed. In some implementations, first and second signals indicative of BEMF of different stator windings may be used to determine a speed-related characteristic. The speed related characteristic may be used to determine an error amount, which may be used to determine a correction factor to control the speed of the spindle motor.

Abstract: A method of controlling a stepping motor, comprising: performing a driving control of driving a rotor at a predetermined step angle; and performing a stop control of giving a driving circuit of the stepping motor a stop instruction for stopping the rotor at a position that is before or beyond a target stop position by a minuter step angle than the step angle in the driving control in a direction in which the rotor is rotated when to stop the rotor at the target stop position.

Abstract: A centrifuge including: a rotor rotating with a sample contained therein; a rotating shaft rotatably engaged with the rotor; a motor rotating the rotor and the rotating shaft; a belt transmitting rotational force of the motor to the rotating shaft; a rotor speed detecting unit detecting a rotation speed of the rotor; a motor speed detecting unit detecting a rotation speed of the motor; and a control unit controlling the motor, wherein the control unit calculates a signal for controlling the rotation speed of the rotor on the basis of a signal from the rotor speed detecting unit and controls the motor on the basis of a signal from the motor speed detecting unit and the calculated signal.

Abstract: A drive system for a multi-phase brushless motor comprises a single current sensor drive circuit, including switch means, switchable between a plurality of states. A controller is arranged to provide pulse width modulated drive signals to control the switch means so as to control the time that the drive circuit switches between said states in each of a series of pulse width modulation periods, and to: determine a demanded voltage parameter set, identify PWM periods during which the demanded voltage parameter set is such that neither two nominal corresponding state times, nor a higher number of equivalent state times producing the same net voltage, in a single PWM period, would allow a predetermined minimum time to be spent in a predetermined number of active states sufficient for current sensing.

Abstract: The present invention can include an automated method controlling the fan speed of computer system cooling fans with altitude and/or fluid density data from a centralized sensor. Such a method can utilize a centralized sensor to determine the altitude/fluid density within an enclosed area. The centralized sensor can be positioned so as to be unaffected by extraneous activities within the enclosed area. The determined altitude/fluid density can be conveyed to a computer system containing one or more cooling fans. The computer system can be located within the enclosed area. Then, the computer system can determine the need for adjusting the speed of the cooling fans based on the altitude/fluid density. When the need for adjustment exists, the speed of the cooling fans can be adjusted in accordance with the altitude/fluid density.

Abstract: A hand-held power tool has an electric drive motor having a drive shaft and a tool connected to the drive shaft and rotatably driven by the drive shaft. The drive motor has a control device that has correlated therewith at least a first operating curve and a second operating curve. The control device operates the electric drive motor in idle according to the first operating curve and operates the electric drive motor under load according to the second operating curve. The first operating curve covers the low power range at low speed and the second operating curve covers a large power range at high speed.

Abstract: A windshield wiper system for use on a hybrid electric vehicle is capable of adjusting the delay between consecutive cycles based on engine state and vehicle speed. The system includes a windshield wiper and a motor coupled to the windshield wiper. A sensor generates an engine speed signal and another sensor generates a vehicle speed signal. A processor in communication with the sensors and wiper motor provides a drive signal to the wiper motor which is based on the engine and vehicle speed.

Abstract: A system for controlling a displacement drive of a motor vehicle includes a manually operable actuator movable over a fixed stroke between a first end position and a second end position. The actuator is biased to a neutral position centrally located between the first and second end positions and provides a signal representative of position of the actuator. A controller receives the signal from the actuator and produces commands for a reversible DC electric motor of the displacement drive device. The commands vary speed of the drive motor based on the position of the actuator such that the speed of the drive motor is zero at the neutral position, increases in one direction as the actuator moves toward the first end position, and increases in the other direction as the actuator moves toward the second end position.

Abstract: A motor driving device is disclosed that includes a first drive circuit that drives a first electric motor and increases a rotational speed of the first electric motor according to an increase in a duty ratio of a pulse signal output from an electronic control unit. The motor driving device also includes a second drive circuit that drives a second electric motor and increases the rotational speed of the second electric motor according to the increase in the duty ratio of the pulse signal. The second drive circuit smooths the pulse signal from the electronic control unit to produce a direct-current voltage. Also, the second drive circuit supplies electric power to the second electric motor by applying the direct-current voltage to the second electric motor.

Abstract: Moderately accurate closed loop speed control of a universal motor is attained without the need for any type of speed sensor. Motor armature (across the brushes) voltage is sensed and supplied to a control circuit for processing along with sensed motor current and zero-crossing information. Integration of the motor armature voltage provides a value which is related to current motor speed. By adjusting the gating angle for triac actuation, the armature voltage integral can be maintained at a desired value associated with a desired motor speed. The sensed motor current is also integrated to provide a speed droop compensation value that is added to the desired value, and the gating angle for triac actuation is adjusted to move the armature voltage integral value to approach the summed value of the speed droop compensation value and desired value.

Abstract: Methods and systems for medical imaging are provided. The system includes a gantry assembly having a stator, a first rotor rotatably coupled to the stator, the first rotor configured to rotate about an examination axis at a first rotational speed, and a second rotor rotatably coupled to at least one of the stator and the first rotor, the second rotor configured to rotate about the examination axis at the first and a second rotational speed, the second rotational speed being greater than the first rotational speed, the first and second rotors configured to be locked in position with respect to each other during rotation at the first rotational speed, the first rotor configured to be locked in position with respect to the stator during rotation of the second rotor at the second rotational speed.

Abstract: A method of configuring a control unit (CPU) of an actuator (ACT) including a motor (MOT) for operating a movable element (COV) of a home automation equipment item (INST) of closure, privacy, sun protection or screening, which comprises: a phase for supplying the motor during which at least one characteristic quantity (MV1, MV2, MZ1, MZ2) of the movement of the movable element is obtained with the aid of a measurement procedure comprising at least one step of integrating a physical quantity supplied by an accelerometer (ACC), at least one quantity (ROT, ROT1, ROT2) internal to the actuator being measured during this supply phase, and a phase for determining a relation (REL) between the characteristic quantity and the internal quantity.

Abstract: In a method for controlling an electric pump drive motor of a power steering device, a high output stage and a low output stage are provided, in which the motor can be operated. Between the two output stages at least one further middle output stage in which the motor can be operated is provided. A switchover between the three output stages takes place as a function of the current consumption of the motor.

Abstract: An apparatus and method for controlling high speed operation of a motor for controlling high speed operation of a motor by estimating the position and the speed of the rotor of a synchronous motor without a PI regulator to eliminate the users' inconvenience and to secure the reliability of the control of a rotor's position and speed of a synchronous motor, which includes: a reference frame transformer that receives triangular coordinate voltages and currents and converts them to static coordinate voltages and currents, a flux observer that receives the converted static coordinate voltages and currents and observes and outputs the flux of the stator, a position estimator that receives the converted static coordinate currents and the observed flux of the stator and estimates and outputs the position of the rotor, and a speed estimator that receives the estimated position of the rotor and estimates and outputs the speed of the rotor.

Abstract: A temperature control apparatus is suitable for use in devices such as consumer electronics devices having different thermal characteristics. According to an exemplary embodiment, the temperature control apparatus includes a fan having a field winding (F3) and a speed controller for providing a speed control signal to the field winding (F3) responsive to a first control signal to control a rotating speed of the fan. First and second terminals of the fan enable operating power to be provided to the field winding (F3) and the speed controller. At least one of the first and second terminals is operatively coupled to a first voltage source. A third terminal of the fan provides the first control signal to the speed controller, and is operatively coupled to a second voltage source.

Abstract: An AC motor speed controller includes a plurality of capacitors that may be selectively switched, by means of controllably conductive switches, into series electrical connection with an AC motor and an AC voltage source to control the speed of the motor. To change the speed of the motor, a control circuit renders a first switch conductive, in response to a first detected AC voltage zero crossing, to charge a first capacitor to a predetermined voltage. The control circuit then renders a second switch conductive, in response to a subsequent second detected AC voltage zero crossing, to charge a second capacitor to the predetermined voltage. The control circuit then renders both switches simultaneously conductive at a predetermined time after a subsequent third detected AC voltage zero crossing. The capacitors will thereby be charged to the same voltage prior to being switched into series with the motor, thereby resulting in reduced acoustic noise when changing motor speeds.

Abstract: A fan module assembly includes at least one a rotatable fan (38) having blades (39) with tips of blades being joined by an annular fan band (42). An electrically conductive squirrel cage (46) is associated with the fan band to rotate therewith. Flux receiving structure (48) is associated with the fan band. A shroud (40) has a shaft (54) with the fan being associated with the shaft so as to rotate about the shaft and with respect to the shroud. Control structure (52) is mounted stationary with respect to the shroud generally adjacent to a portion of the fan band. The control structure is constructed and arranged to generate a changing magnetic field, generally at the radius of the fan band, which interacts with the flux receiving structure and the squirrel cage to cause the fan to be driven by tangential force.

Abstract: Embodiments of the present invention provide a low noise and high efficiency fan speed controller. The fan speed controller generates a pulse width modulation signal. The pulse width modulation signal is utilized to switch mode convert a supply voltage into a linear voltage. The voltage level of the linear voltage is a function of the pulse width modulation signal. The linear voltage is utilized to control the operating speed of a direct current fan.

Abstract: An apparatus is provided and includes a power source, a system board on which an electrical component is installed, a heat sink including a plurality of heat transfer surfaces to contact the electrical component and to thereby remove heat from the electrical component, a fan reversing control card coupled to the system board and configured to generate normal and reverse cycle rotation signals, and a fan coupled to the fan reversing control card and configured to receive the normal and reverse cycle rotation signals and to thereby operate in normal and reverse cycles in which the fan rotates in first and second directions, respectively, the fan being disposed within the computer such that the first and second directional rotations of the fan generate air flows in first and second directions with respect to the heat transfer surfaces, respectively.

Abstract: A method for attenuating switching noise from back electromotive force (EMF) observations in a motor is described. The motor is controlled by pulse width modulation (PWM) signals provided at a PWM frequency. The method comprises sampling back EMF observed in the motor at a sampling frequency at least two times greater than the PWM frequency to obtain over-sampled back EMF readings. The oversampled readings may be used in a raw or filtered form to commutate the motor. A system implementing the method is also described.

Abstract: Systems and methods for controlling cooling fan speed based on ambient noise levels are disclosed. Some embodiments may include a method for controlling cooling fan speed. The method may include receiving an indication of a current ambient noise level at a computer system and predicting noise due to one or more cooling fans at an expected operator position for the computer system based on a first speed of the cooling fan(s). Embodiments of the method may also include comparing the predicted operation position noise due to the cooling fan(s) with the current ambient noise level and adjusting the cooling fan(s) to a second speed based on the comparison between the predicted operator position noise and the current ambient noise level. Other embodiments are disclosed and claimed.

Abstract: The invention relates to a method for detecting unbalanced conditions of a rotating load driven by a synchronous electric motor (3) in washing machines (1) and similar rotably drum (2) household appliances and wherein at least a transient step is provided with variation of the angular speed (w) of the rotably drum (2). The method provides the following steps: constantly monitoring the instantaneous current (Iq) absorbed by the motor calculating in real time the unbalanced mass (m) on the basis of the variation (?) of the current (Iq) and starting from a predetermined reference and by applying a calculation formula representative of the kind of load imbalance.

Abstract: Methods and apparatuses implement a bi-directional model train communications protocol compatible with existing uni-directional communications protocols. In one specific embodiment, the existing uni-directional Lionel Train Master command set is expanded utilizing the checksum error nibble to flag an alternative command signal format. This expanded command set is in turn utilized to transmit a command inquiry signal from the base unit to a specifically addressed element. The addressed element in turn transmits a response based upon the expanded command set. Older model railroad elements not configured to recognize the expanded command set, regard the command inquiry signal as a transmission error and are unaffected. Newer model railroad elements not specifically addressed by the command inquiry signal ignore the command and continue operation.

Abstract: A motor controller comprises an angular position module that determines an angular position of a disk. A spin-up module performs a spin-up of the disk. A ramp-up module ramps up a speed of the disk after the spin-up. A speed control module controls the speed of the disk based on a control program that is downloaded to the motor controller during a boot-up operation of a disk drive. The angular position module determines the angular position of the disk before handover of control to the control program.

Abstract: A system and method for controlling an actuator includes a control module that communicates with a plurality of switching devices to generate current through a voice coil motor during a first time period so that an actuator arm rotates in a first rotational direction in response to the current. The control module controls the switching devices to discharge the current from the voice coil motor during a second time period less than the first time period so that the first rotational direction of the actuator arm is maintained after discharging the current. The control module further includes a back electromagnetic force (bemf) module for determining a bemf voltage after controlling the switching devices to discharge the current, and an actuator arm speed control module for determining an actuator arm speed in response to the bemf voltage.

Abstract: The air circulation fan associated with a radiator of some machines may include an automatic reversing purge cycle that is utilized to dislodge material from the radiator and/or intake screen of the cooling system housing. The purge cycle is locked out when a person may be in the vicinity of the air intake screen of the machine. A controller determines that a person may be in the vicinity of the air intake screen when the machine is idle stationary, such as by determining that a parking brake is engaged. By locking out the purge cycle during machine idle stationary conditions, the risk of blowing dislodged dirt and/or debris onto a person, who may be servicing the machine or accessing an operator station, can be avoided.

Abstract: An electrodynamic machine has a winding and a switching arrangement effectively dividing the winding into individually controllable portions. During a first operating condition, current flows through the entire winding in a manner controlled by the switching arrangement. In a second condition, the switching arrangement restricts current flow to only a portion of the winding. The second condition effectively reduces the inductive capacity of the winding.