Abstract: Examples include a method of control implemented in a variable speed drive for controlling an electric motor during backspin, wherein the method includes: determining, by the variable speed drive, a mechanical power value occurring at a backspin speed and an estimated load torque; determining, by the variable speed drive, a specific electrical losses profile occurring at a motor flux level, wherein the specific electrical losses profile coincides with the mechanical power value; determining, by the variable speed drive, a flux reference and a speed reference to be applied to the motor to coincide with the specific electrical losses profile; and controlling, by the variable speed drive, the backspin speed of the motor to maintain the coincidence with the specific electrical losses profile.

Abstract: A power supply controller includes a driver having a circuit board and controlling an operation of an electric oil pump, a control unit controlling power supply to the driver, a board temperature sensor detecting a temperature of the circuit board; and an oil temperature sensor detecting a temperature of a working oil of a transmission as an oil temperature. The control unit executes energization prohibition control for prohibiting power supply to the driver when the temperature of the circuit board detected by the board temperature sensor exceeds a predetermined first threshold temperature, and executes cancellation determination for determining whether to cancel the energization prohibition control based on the oil temperature detected by the oil temperature sensor during execution of the energization prohibition control.

Abstract: Voltage measurement calibration methods and junction circuits. In one embodiment, the junction circuit includes a capacitor and a voltage adjustment circuit. The junction circuit is electrically coupled to an output of a capacitive voltage divider circuit. The capacitor is electrically coupled between the output of the capacitive voltage divider circuit and a reference terminal. The voltage adjustment circuit is electrically coupled between the output of the capacitive voltage divider circuit and an output of the junction circuit. The voltage adjustment circuit includes an adjustable impedance component configured to adjust a voltage gain of the voltage adjustment circuit.

Abstract: A starter/generator arrangement includes a starter/generator, a power converter electrically connected to the starter/generator, and coolant circuit with a pump and a condenser in fluid communication with the power converter. The power converter is arranged to flow start mode electrical power in a first direction in a start mode and a second direction in a generate mode. The coolant circuit fluidly couples the pump to the condenser for storing heat in a coolant disposed within the coolant circuit while flowing the start mode electrical power in the first direction. Gas turbine engines and methods of cooling starter/generator arrangements are also described.

Abstract: Systems and methods for reducing current imbalance in a motor, where one embodiment comprises a system having an ESP installed in a well, an electric drive, and a power cable coupled between the drive and the ESP's motor. The electric drive generates output voltage waveforms (e.g., PWM waveforms) for multiple phases that may have different impedances. The system monitors the current of each phase at the output of the electric drive and determines a current imbalance between the phases. The drive generates voltage adjustments (e.g., duty cycle adjustments) corresponding to the respective phases, and applies each voltage adjustment to the corresponding voltage waveform. For example, the drive may determine an average of the phase currents, determine the difference between each phase current and the average, and multiply the result by a gain factor to generate the voltage for each phase. The process is iteratively performed to reduce the current imbalance.

Abstract: An oil field pump installed within a pipe that connects to an oil field, feeds accumulated extraction oil in a predetermined direction and includes a rotor, a stator mounted on the outer circumference of the rotor, a flow path for flow of the extraction oil connecting an area formed within the rotor to an area formed between the rotor and the stator, a thrust bearing that supports the axial weight of the rotor and the stator, and a supply pipe that supplies a portion of the extraction oil in the flow path to the thrust bearing. The thrust bearing includes a protrusion part fixed to the outer circumference of the rotor and rotating as one piece with the rotor, and a facing part fixed to the stator and facing opposite a surface in the axial direction of the protrusion.

Abstract: An actuation system for a resonant linear compressor (50) is disclosed, applied to cooling systems, the latter being particularly designed to operate at the electromechanical frequency of said compressor (50), so that the system will be capable of raising the maximum power supplied by the linear actuator, in conditions of overload of said cooling system. Additionally, an actuation method for a resonant linear compressor (50) is provided, the operation steps of which enable one to actuate the equipment at the electromechanical resonance frequency, as well as to control the actuation thereof in over load conditions.

Abstract: A displacement pump arrangement, method for operating the displacement pump arrangement and a control device for controlling the displacement pump arrangement provide rotational-speed-variable control of an expeller pump unit for feeding a fluid. The arrangement includes an expeller pump and a drive, the drive being composed of an electric drive motor and a frequency converter, and a control device. The control device controls a state value such as a final pressure of the expeller pump a setpoint value. The control device detects state values of a control variable are supplied by the drive, in particular relating to the position, rotational speed and torque of the drive motor, and adjusts the displacement pump output to reach the setpoint value without using sensors.

Abstract: A method for detecting head crashing in a linear compressor includes sampling a rolling average of a peak applied voltage and a desired peak current each time that a current controller adjusts the desired peak current. The method also includes calculating a linear regression for a predicted peak applied voltage as a function of the desired peak current, calculating the predicted peak voltage for the motor of the linear compressor with the linear regression and a current value for the desired peak current from the current controller, and establishing that a piston of the linear compressor is soft crashing when the predicted peak voltage is different than the current value for the rolling average of the peak applied voltage by more than a threshold value.

Abstract: This electric compressor includes a compressor which rotates to compress a fluid, a motor which rotatably drives the compressor, and a control unit which controls current supply to the motor using first and second components. An allowable current for first and second components exposed to the same temperature is set to be smaller in the second component than in the first component. The second component is disposed at a place in which cooling capability is greater than that of the first component so that allowable power of the second component at rated use is greater than allowable power of the first component. This electric compressor includes a temperature sensor which detects the temperature of the first component and a calculation unit which outputs an alarm signal when the detected temperature and a current flowing in the first component satisfy a predetermined condition.

Abstract: An electric compressor includes a compression portion discharging a high pressure refrigerant by compressing a low-pressure drawn refrigerant, an electric motor driving the compression portion with a rotation of a rotor, a motor drive circuit driving the electric motor, an intermediate pressure port through which an intermediate pressure refrigerant is introduced into the compression portion, and a controller performing a rotation control of the rotor. When the controller stops the electric motor in a two-step compression mode in which the intermediate pressure refrigerant is introduced into the compression portion, the controller stops the rotor rotating by performing short-circuit braking on the electric motor and then fixes a rotational position of the rotor at a predetermined rotational position by performing direct current excitation on the electric motor.

Abstract: A pumping system for at least one aquatic application includes a motor coupled to a pump and a controller in communication with the motor. The controller is adapted to determine a first motor speed of the motor, determine a reference power consumption using a reference flow rate and a curve of speed versus power consumption for the reference flow rate, and generate a difference value between the reference power consumption and a present power consumption. The controller drives the motor to reach a steady state condition at a second motor speed based on the difference value.

Abstract: Before sensorless control is performed on a three-phase brushless motor by sequentially switching between six energization modes each for selecting two phases to be energized from the three phases, the initial position of the rotor is estimated based on a change in a second induced voltage by: momentarily energizing the three-phase brushless motor according to each of the six energization modes, and detecting six first induced voltages each generated in a non-energized phase by the energization; calculating three induced voltage differences corresponding respectively to three non-energized phases, each induced voltage difference being a difference between two of the six first induced voltages that are detected during energization according to two energization modes that share a non-energized phase; and energizing the three-phase brushless motor according a predetermined energization mode selected based on the three induced voltage differences, and detecting the second induced voltage generated in a non-energi

Abstract: A method for protecting a resonant linear compressor (14) including structural resonance frequencies (wE) and a motor that is fed by feed voltage (Va) that has amplitude (A) and a drive frequency (wA), both controlled according to the equation A·sin(wt). The protection method is configured so as to include the step of preventing feed to the motor at drive frequencies (wA) that have at least one harmonic coinciding tithe the structural resonance frequency (wE) of the resonant linear compressor (14). A protection system of a resonant linear compressor (14) includes an electronic control (30) configured to prevent feed to the motor at the drive frequencies (wA) that have at least one harmonic coinciding with the structural resonance frequency (wE) of the resonant linear compressor (14).

Abstract: Techniques are provided for protecting a rotary positive displacement pump, e.g., using a signal processor that receives signaling containing information about power, torque, speed, viscosity and specific gravity related to the operation of a pump; and determines whether to enter an enhanced pump protection mode for the rotary positive displacement pump based at least partly on a relationship between an actual corrected tune ratio and a tuned ratio set point (Tune Ratio SP). The signal processor may determine if the actual corrected tune ratio is less than or equal to the actual corrected tune ratio set point (Tune Ratio SP), and if so, then to enter the enhanced pump protection mode, else continues to use a basic pump protection mode, and also determines the actual corrected tune ratio based upon a ratio of an actual corrected power (PAcorr) divided by a tuned corrected power (PTcorr) at a specific operating speed.

Abstract: Systems and methods for providing override control for a feedwater pump recirculation valve are provided. According to one embodiment, a system may include a controller and a processor communicatively coupled to the controller. The processor may be configured to receive one or more measurements associated with pump motor power driving feedwater pump flow. The feedwater pump recirculation valve may be configured to maintain a predetermined minimum recirculation flow through the feedwater pump by regulating recirculation pump flow through a recirculation line. The processor may be also configured to calculate, based at least in part on the one or more measurements, the recirculation pump flow, and compare the recirculation pump flow to the predetermined minimum recirculation flow. Based at least in part on the comparing, the processor may selectively provide an override control signal to the feedwater pump recirculation valve to selectively modify the recirculation pump flow.

Abstract: A dynamo-electric machine, for example a marine propulsion unit, includes a stator and a rotor in the form of an impeller. The impeller is rim-driven and includes an annular core of ferromagnetic material, on which are provided layers in the form of an environmental enclosure and electrically conductive sleeves. Appropriate selection of the materials and thicknesses of the layers enables the starting and normal running performance of the machine to be optimized.

Abstract: Systems and methods for controlling and monitoring multiple fans in conjunction with a single fan controller are described. One such system includes the single fan controller, a plurality of fans, and a multi-fan monitor configured to receive a signal indicative of fan speed for each of the fans, (a) determine, for a selected fan of the fans, whether the respective received fan speed signal is within an expected fan speed range, if the respective received fan speed signal is not within the expected fan speed range transmit a signal to the single fan controller indicative of a fan failure, if the respective received fan speed signal is within the expected fan speed range transmit a signal to the single fan controller indicative of the fan speed for each of the fans, and return to (a) to test a next selected fan of the fans.

Abstract: A ramp-up optimizing vacuum pump system comprising a vacuum pump in fluid communication with a blower and one or more apparatus and operable to create a vacuum flow from the one or more apparatus through the outflow of the vacuum pump. The blower is positioned between the vacuum pump and one or more apparatus. The blower includes a blower motor which is controlled by a blower controller and a unit controller. The unit controller increases the blower speed at a predetermined ramp-up rate. The blower controller optimizes the ramp-up rate of the blower based on the operating conditions by monitoring the current draw of the motor and the blower speed. If at any time the current draw exceeds a predetermined maximum at a certain blower speed, the blower controller maintains the blower speed until the current draw decreases below the maximum and then continues ramp-up up at the predetermined ramp-up rate.

Abstract: A digital filter is configured to convert, into a digital value, the duty ratio of a control signal subjected to pulse width modulation according to a target toque to be set for a fan motor to be driven. A sampling circuit is configured to perform sampling of the output value of the digital filter at a sampling timing that is asynchronous with respect to the cycle of the control signal, so as to generate a torque instruction value. A driving circuit is configured to drive the fan motor according to the torque instruction value thus generated.

Abstract: A system includes a motor, an inverter bridge, a voltage detection circuit, and a controller. The motor has a stator and a rotor. The inverter bridge is configured to provide a voltage to the stator, and includes a first switch connected in a series-type relationship with a second switch, a first diode coupled across the first switch, and a second diode coupled across the second switch. The voltage detection circuit is configured to detect a back EMF voltage in the winding. The controller is configured to control the first switch and the second switch to drive the motor, and to receive an indication of the back EMF voltage in the winding from the voltage detection circuit. The controller is also configured to determine a fault has occurred, and to drive one of the first switch and the second switch when a fault has occurred.

Abstract: A linear motor (10), a linear compressor (100), a method of controlling a linear compressor (100), a cooling system (20) and a system of controlling a linear compressor (100) to operate a linear compressor (100) in resonance in it's the greatest possible efficiency throughout its operation are described.

Abstract: A fan rotation speed controlling device includes a first transistor, a second transistor, a third transistor, a fourth transistor, and at least one heat dissipation fan. The first transistor receives a pulse-width modulation (PWM) signal. The second transistor and the third transistor amplify the PWM signal. The fourth transistor receives the amplified PWM signal and changes its own working state according to the amplified PWM thereby controlling the magnitude of an output voltage. Consequently, the heat dissipation fan changes its rotation speed according to variation of the output voltage. The fan rotation speed controlling device is applicable to and can control the rotation speeds of a plurality of electrically connected fans which are of different specifications.

Abstract: The present invention concerns an infusion device for liquid medicines and the like, including at least one main body associated with at least one tank of liquid medicine, at least one peristaltic pump having at least one rotor coupled with at least one press roller that can be pushed so as to engage with a tubular duct wound so as to form at least one complete ring, abutting on the inner wall of at least one casing of said peristaltic pump, and including two substantially adjacent portions of said tubular duct. The device includes one control processor, associated with the motor of the rotor, including means for adjusting the speed of the rotor suitable for increasing the speed of said rotor in at least one sector of the complete revolution carried out by said rotor.

Abstract: A driving device for a brushless DC motor having at least one coil ma include a voltage zero crossing detection unit to where an induced voltage becomes zero; a detection period setting unit to set at least one detection period synchronously with the voltage zero crossing point; a coil voltage detection comparator to compare a terminal voltage generated from one end of the coil with a threshold voltage, and generate a coil voltage detection signal indicating a comparison result; a current phase detection unit to generate a phase detection signal indicating a relationship between a phase of a coil current flowing through the coil and a phase of the induced voltage; a driving signal synthesis unit to generate a driving control signal based on the phase detection signal; and a driving circuit to drive the brushless DC motor based on the driving control signal.

Abstract: A fuel supply apparatus includes a fuel pump having an electrically driven motor. A controller is connected to the motor of the first fuel pump and is capable of determining an estimated pressure based on a value of current supplied to the motor and a rotational speed of the motor. The controller controls the motor so that the estimated pressure becomes relatively equal to a target pressure.

Abstract: A blower system includes a blower motor and an inverter in electrical communication therewith. The blower motor is mechanically coupled to a blower configured to generate an airstream having an airflow rate. The inverter is configured to provide a motor drive signal to the motor. A flow rate calculator is configured to determine a calculated airflow rate from motor operating parameters of the blower motor using a mathematical model of the airflow rate.

Abstract: Dosing device (100) for dispensing a specified vol? ume of liquid, comprising an electromagnet (1 11) and being adapted to hold a pump (1 12) with a magnetisable pumping member (1 10) displaceable under the action of the electromagnet when the pump is held by the dosing device. The dosing device further comprises a portable voltage source (1 13) adapted to energize the electromagnet by repeated current pulses and to measure the current intensity at least once per pulse, thereby estimating the charge amount in each pulse, until a total charge amount corresponding to the speci? fied volume of liquid to be dispensed has been supplied. A method including pulse-wise activation of an electromagnet actuating a pump having a magnetisable pumping member is also disclosed.

Abstract: The invention provides a portable DC cooling fan that performs the dual function of a cooling fan and a sleep aid by generating air movement and white noise useful for inducing sleep. The portable device includes a DC axial fan that blows air in one direction and is under the control of an electrical control system that receives power through an AC/DC adapter. The electrical control system includes one or more user interface switches through which a user can select fan speed and optionally, set the fan on oscillation mode, and thereby simulating airflow and the sounds of a standard oscillating fan without undergoing rotation. The portable DC cooling fan of the invention includes a housing having a plurality of openings on its front and rear surfaces that enable maximum air flow through the device. The invention also provides an article of manufacturer comprising an AC/DC adapter packaged with a portable DC cooling fan of the invention.

Abstract: A reciprocating compressor is provided that reciprocates a piston inside a cylinder as a linear motor is driven, to compress a refrigerant by sucking the refrigerant into a compression space between the cylinder and the piston, and then discharge the same. The piston is operated at a top dead center position and in a resonance state by symmetrically applying a voltage even if a load varies. An elastic coefficient of mechanical spring is set in consideration of a degree of shift of the piston influenced by gas springs varied by the load, and an initial value of the piston to maintain stroke of the piston is set so as to correspond to a required cooling capacity condition.

Abstract: The present invention relates to a control device for a radiator fan, in particular for a radiator fan of a motor vehicle, having an external control device which is designed to generate a controlled variable for an electric motor of the radiator fan according to a first predefined setpoint value, and having an internal control device which is designed to control the motor current of the electric motor of the radiator fan according to a predefined first motor current maximum value if the controlled variable which is generated by the external control device assumes such a value that the motor current exceeds the predefined first motor current maximum value. The present invention also relates to a radiator fan arrangement and to a method for controlling a radiator fan.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibrating procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibrating procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: A method and apparatus for a pump control system. One or more embodiments of the invention include a pump controller that can perform a self-calibrating procedure, can provide precise motor speed control, can provide a limp mode before shutting down the motor when system parameters are exceeded and/or fault conditions occur, can detect fault conditions, and can store fault conditions for later retrieval.

Abstract: A pumping system includes a pump for moving water. In one aspect, this is in connection with performance of an operation. The system includes a variable speed motor operatively connected to drive the pump. A value indicative of flow rate of water is determined and the motor is controlled to adjust the flow rate indicative value toward a constant. A value indicative of flow pressure is determined and the motor is controlled to adjust the flow pressure indicative value toward a constant. A selection is made between flow rate control and flow pressure control. In another aspect, the pump is controlled to perform a first operation, and is operated to perform a second water operation. Control of operation of the pump to perform the first water operation is altered in response to operation of the pump to perform the second operation.

Abstract: An infusion system and method for controlling the fluid flow from a pump includes a pump system that has a controller that utilizes an algorithm to control the flow rate of fluid through tubing. A plurality of electrodes operatively contacts an electrically conductive portion of the tubing that is also acted upon by the pump system. The electrodes monitor electrical properties of the tubing and provide an electric signal indicative thereof to the controller, which varies the flow rate of the fluid through the tubing as a result of the electric signal.

Abstract: A system and method are provided for reducing the energy consumed by a pump jack electric motor by reducing the supply voltage to the motor when the motor would be generating energy in open loop mode. By substantially eliminating the energy generation mode, the braking action of the utility grid in limiting the acceleration of the motor and system that would otherwise occur is substantially removed. The motor and system will speed up, allowing the natural kinetic energy of the cyclic motion to perform part of the pumping action. In particular, when the energy consumption for the electric motor connected with the device having a rotating or reciprocating mass goes to zero, the line voltage to the motor is switched off, causing the frequency of the voltage across the motor terminals to increase. When the period of the voltage across the motor terminals returns to substantially the same as the period of the line voltage, the line voltage is switched on or reapplied to the motor.

Abstract: Vibration protection in a compressor system with a variable speed compressor may include operating a variable speed compressor of a compressor system at a first frequency, measuring a vibration of the compressor system at the first frequency, determining whether the vibration exceeds a maximum vibration value, and operating the variable speed compressor at an average frequency equivalent to the first frequency, when the vibration exceeds the maximum vibration value, by identifying an allowed upper frequency and an allowed lower frequency, calculating an upper operating time and a lower operating time, and operating the variable speed compressor at the allowed upper frequency for the upper operating time and the allowed lower frequency for the lower operating time.

Abstract: The present invention provides a pumping system for moving water of a swimming pool, including a water pump and a variable speed motor. In one example, a target volume amount of water and an operational time period is provided, and the operational time period is altered based upon a volume of water moved. In another example, operation of the motor is altered based upon the volume of water moved. In addition or alternatively, a target flow rate of water to be moved by the water pump is determined based upon the target volume amount and a time period. In addition or alternatively, a plurality of operations are performed on the water, and a total volume of water moved by the pump is determined. In addition or alternatively, an optimized flow rate value is determined based upon power consumption.

Abstract: A pump control system which detects a fluid condition in a pump is disclosed. The pump control system may include a control event based on the fluid condition in the pump. The pump control system may detect a fluid condition in the pump by monitoring the frequency response of the pump.

Abstract: An apparatus for controlling an electric oil pump that can determine the occurrence of idling even in a region in which determination based on a load of the electric oil pump becomes difficult. The apparatus for controlling an electric oil pump according to one embodiment of the invention sets a target number of revolutions for determination tNset higher than a required number of revolutions tNreq corresponding to an operation request of the electric oil pump, and executes control of an electric motor so that the number of revolutions N of the electric oil pump approaches the target number of revolutions for determination tNset. A load (phase current Ii) of the electric oil pump is detected while executing the control of the electric motor, and the occurrence of idling in the electric oil pump is determined based on a detected pump load (Inrm, IidI).

Abstract: Embodiments of the invention provide a pumping system for at least one aquatic application. The pumping system includes a pump, a motor coupled to the pump, and a controller in communication with the motor. The controller determines a first motor speed, obtains a reference flow rate, determines a present flow rate, and determines a present power consumption. The controller calculates a difference value between the reference flow rate and the present flow rate, and uses at least one of integral, proportional, and derivative control to generate a second motor speed based on the difference value. The controller attempts to drive the motor at the second motor speed until reaching a steady state condition.

Abstract: Some embodiments of the invention provide a pumping system for at least one aquatic application. The pumping system includes a pump, a motor coupled to the pump, a user interface associated with the pump designed to receive input instructions from a user, and a controller in communication with the motor. The controller determines a power parameter associated with the motor and compares the power parameter to a predetermined threshold value. The controller triggers a safety vacuum release system based on the comparison of the power parameter and the threshold value.

Abstract: A method of detecting impact or collision between a cylinder (2) and piston (1) driven by a linear motor of a gas compressor includes the steps of: i) obtainment of a reference signal (Sr) associated to an electrical output of the linear motor before the piston attains the upper dead center; ii) obtainment of a detection signal (Sd) associated to the electrical output of the linear motor after the piston attains the upper dead center; iii) comparison between the reference signal (Sr) and the detection signal (Sd); and iv) record of occurrence of impact when the result of comparison of step iii indicates that the detection signal (Sd) presents a variation deriving from impact between the cylinder and the piston, considering a pre-established tolerance. Also disclosed is an electronic detector device , a gas compressor (100) and a control system.

Abstract: An electric compressor 10 includes a compression mechanism 11, an electric motor 12 driving the compression mechanism 11, and a control portion 13 controlling to drive the electric motor 12, incorporated into a single casing, and further includes a temperature detector 14 detecting a temperature of one or more components constituting one or both of the control portion 13 and the electric motor 12, and a current detector 15 detecting a current flowing through the component. When the temperature detected by the temperature detector 14 is a temperature Td, the current detected by the current detector 15 is a current Id, and a current corresponding to the temperature Td at a temperature characteristic relating to the current specific to the component is a current Ia(Td), the control portion 13 stops driving the electric motor 12 on the basis of a result of comparison between Ia(Td) and Id.

Abstract: An actuation system for a resonant linear compressor (50), applied to cooling systems, the latter being particularly designed to operate at the electromechanical frequency of said compressor (50), so that the system will be capable of raising the maximum power supplied by the linear actuator, in conditions of overload of said cooling system. Additionally, an actuation method for a resonant linear compressor (50) is disclosed, the operation steps of which enable one to actuate the equipment at the electromechanical resonance frequency, as well as to control the actuation thereof in over load conditions.

Abstract: A compressor overload protection device utilizes a first electrode of an electric connector to electrically connect a first OLP overload protection loop that is electrically connected to a first power line of an external power source. In addition, a second OLP overload protection loop is connected to a second electrode and a third electrode of the electric connector, and a capacitor is electrically connected between the third electrode and the first electrode. When the operation of the compressor is overloaded, the first and second OLP overload protection loop can provide proper protection mechanism with respect to the first power line and the second power line to prevent a motor of the compressor from being overheated and damaged, and the electrodes of the electric connector can be effectively prevented from exploding.

Abstract: A snowmobile having an electronic oil pump fluidly connected to an oil tank thereof is disclosed. The electronic oil pump is fluidly connected to an engine of the snowmobile for delivering lubricant to the engine. An electronic control unit is electrically connected to the electronic oil pump for controlling actuation of the electronic oil pump. A method of operating an electronic oil pump is also disclosed.

Abstract: A circulation pump for a conveyed liquid is provided. The circulation pump has an electric motor, which is electronically commutated, has a rotor, a stator and a motor circuit. An impeller is connected in a rotationally fixed manner to the rotor. The electric motor has an evaluation device for determining a flow rate of conveyed liquid through the circulation pump from a rotational speed of the rotor and/or a power consumption of the electric motor. At least one signal output is provided, by which a flow rate signal and/or flow rate-dependent switching signal can be supplied by the circulation pump.

Abstract: A linear compressor for adjusting a variable rate of a cooling capacity is provided. The linear compressor may include a fixed member having a compression space formed therein, a movable member linearly reciprocated in the fixed member to compress a refrigerant drawn into the compression space, one or more springs provided to elastically support the movable member in the motion direction of the movable member, a motor unit including a motor connected to the movable member to linearly reciprocate the movable member in the axial direction and a capacitor connected in series to the motor, and a motor control unit controlling an AC voltage applied to the motor to adjust a variable rate of a cooling capacity by the reciprocation of the movable member.