Abstract: This method for controlling an asynchronous electrical motor (32) of a compressor system (10), comprises:—connecting (100) a capacitor bank (50) of the compressor system (10) in parallel with a first electrical motor (32) of the compressor system, this connection comprising connecting capacitors (52, 54, 56) of the capacitor bank (50) to windings of the stator of the first motor (32), by operating a switch unit (60) of the capacitor bank connected to an internal power bus (12);—starting (102) the first asynchronous electrical motor (32), by providing an input electrical current to the windings of the first motor (32) from the internal power bus (12);—disconnecting (108) the capacitor bank (50) from said first motor (32) once said motor (32) has started, this disconnection comprising disconnecting said capacitors (52, 54, 56) from the windings of the motor (32).

Abstract: A motor control system for induction-type AC electric motors having starting and run windings has a multiphase VFD drive with first and second phase outputs. A switching device with a first position, where a first output of the VFD drive is coupled to the run winding and a second output of the VFD drive couples to the start winding; and with the switching apparatus in second position, the run winding of the AC electric motor couples to an AC line input and the start winding of the AC electric motor couples through a capacitor and start switch to the AC line input. With the switching device in the first position, the second output of the VFD is configured to discontinue driving the start winding of the motor after the motor begins rotating.

Abstract: Disclosed are a variable power motor and an intelligent controller therefor. The motor includes a rotor, a stator, a housing, stator windings and terminals. The stator windings are formed by embedding the same stator core into multiple series windings. Various series nodes of the stator windings, each serving as a power supply terminal with different power, are respectively led out individually. The various series windings of the stator respectively control, by means of the intelligent controller, the switching on and off of multiple switching switches. The soft-start and soft-stop of the motor can be realized, and a load is automatically tracked to regulate the power of the winding during operation, so as to obtain a power-saving effect.

Abstract: The invention relates to a method for starting an electronic drive circuit for the windings of an electric motor. A control unit, which is connected to a voltage source, is provided as well as a capacitor connected via a system switch element to the connecting terminals of the voltage source. The capacitor is connected across the input terminals parallel to the drive circuit. An operating circuit controls the system switch element. In order to start the motor, the operating circuit closes the system switch element and charges the capacitor and after the charging of the capacitor, opens the system switch element again. A test step is then started by the control unit, the drive circuit being supplied exclusively by the capacitor voltage (UC) during the test step.

Abstract: An apparatus and method for controlling an operation of a compressor are disclosed to enhance a compressor efficiency in each operation mode in operating a compressor in a power mode or power saving mode according to an external load. The apparatus for controlling an operation of a compressor, including: a controller that generates a control signal to select an operation mode of the compressor according to an operation load of the compressor; a compressor motor that includes a main coil and a sub-coil and is driven in one of a plurality of operation modes according to a control signal of the controller; and a power supply unit that applies power via capacitors each having a different capacitance to the sub-coil of the compressor motor according to a control signal of the controller.

Abstract: An input circuit includes an interface structured to output a logic signal from an alternating current signal of a pair of elongated conductors. A load is switchable to the elongated conductors. A processor outputs a control signal to switch the load to the elongated conductors asynchronously with respect to the alternating current signal for a first predetermined time, inputs the logic signal, determines if the input logic signal is active a plurality of times during the first predetermined time and responsively sets a first state of the alternating current signal, and, otherwise, sets an opposite second state of the alternating current signal, and delays for a second predetermined time, which is longer than the first predetermined time, for the opposite second state before repeating the output, and, otherwise, delays for a third predetermined time, which is longer than the second predetermined time, for the first state before repeating the output.

Abstract: A sanitary dispenser, particularly a paper or towel dispenser, contains a housing, in which a sanitary product to be dispensed and a discharge unit for the sanitary product to be dispensed can be arranged. An electric motor is provided for the discharge unit, the electric motor being activatable in a non-contact manner by a capacitive sensor from outside of the housing. The sensor capacitance of the capacitive sensor is formed by a planar electrode disposed inside the housing and by a surface of a body part and/or an object arranged outside of the housing.

Abstract: Entry of a synchronous speed of a rotor can be facilitated by increasing a starting torque by adjusting a magnetization application time for magnetizing the rotor according to whether or not a starting capacitor is used. The present invention includes: a control unit that outputs a control signal for controlling an application time of a magnetizing current according to whether or not a starting capacitor is used; and a switch that supplies power to an exciting coil according to the control signal outputted from the control unit.

Abstract: A motor start circuit for an induction motor includes a start switch device serving the purpose of interrupting the current or voltage flow through the start winding after the start of the motor. The motor includes a main winding and a start winding, which are supplied with alternating current or voltage from a mains power supply.

Abstract: An electric motor (10) drives a compressor (40) of a heat pump system in a laundry machine, e.g., a tumble dryer. The electric motor (10) is an asynchronous motor. The electric motor (10) includes a main coil (12) and an auxiliary coil (14). A control unit (22, 24, 26) is dedicated to the electric motor (10). The control unit includes capacitance circuitry including at least one capacitor (22, 24). The main coil (12) is parallel-connected to a series including the auxiliary coil (14) and the at least one capacitor (22, 24). The main coil (12) is connected or connectable to a power source (34). The capacity of the capacitance circuitry is variable depending directly or indirectly on parameters including, e.g., the actual torque of the electric motor (10). Further, the present invention relates to a method for operating the laundry machine with the heat pump system (10).

Abstract: An air conditioner having two compressors enables, when one compressor is started, the phase advance capacitor for the other compressor to be temporarily separated and used in parallel with the phase advance capacitor for the one compressor. These compressors can have an increased starting torque without using a starting capacitor.

Abstract: A motor start circuit for an AC induction motor employs a DC relay whose NC contacts are placed in series with the start capacitor. A half full-wave rectifier arrangement has an AC input connected to the junction of the relay switch and the start capacitor, and DC outputs applied across the relay actuator coil. In the event of intermittent application of power to the motor, any residual charge on the start capacitor will feed current to the actuator coil to hold the relay switch open until the residual charge has decayed sufficiently, to avoid damage to the motor from capacitive discharge. A high magnetic retentivity core can be used to hold the relay off for sufficient time for stored energy to dissipate.

Abstract: Entry of a synchronous speed of a rotor can be facilitated by increasing a starting torque by adjusting a magnetization application time for magnetizing the rotor according to whether or not a starting capacitor is used. The present invention includes: a control unit that outputs a control signal for controlling an application time of a magnetizing current according to whether or not a starting capacitor is used; and a switch that supplies power to an exciting coil according to the control signal outputted from the control unit.

Abstract: Current consumption during the starting process of a single-phase a.c. asynchronous motor is reduced by an apparatus including a thermistor which can be mounted in series with the main winding of the motor. A starting capacitor can be mounted in series with an auxiliary winding, and current and voltage peaks of the starting capacitor can be reduced by a posistor. The thermistor is mounted in series with the main winding at the beginning of the starting process, and can be bridged by a switch once the starting process is completed.

Abstract: The inventive method makes it possible to feed an alternating current electric motor used for operating a rolling shutter in a building by means of a gear whose performance substantially varies when a movable element drives or is driven by the rolling shutter. The electric motor is supplied, in certain phases, at a reduced tension, wherein the motor slipping measuring a relative speed deviation with respect to a zero running torque speed remains less the motor slipping when the rotor thereof ruts at a nominal speed at least if the rolling shutter does not meet obstacles. The drive for the rolling shutter for carrying out said method is also disclosed.

Abstract: A device for detecting disconnection for use in a stepping motor driver is provided having a driver circuit 3 which comprises a pair of windings 21, 22 wound in a bifilar turn arrangement; a pair of MOSFETs 1, 2 connected to the other end of each winding 21, 22; a common current detecting resistor 4 connected between MOSFETs 1, 2 and ground; a first reference voltage generator 34 for producing a first reference voltage Vt1; a second reference voltage generator 40 for producing a second reference voltage Vt2 lower than first reference voltage Vt1; a decision circuit 8, 8b for comparing the detection voltage on current detecting resistor 4 with second reference voltage Vt2 to produce an alarm signal when detection voltage is higher than second reference voltage Vt2; and a disconnection detector 11 for receiving an alarm signal from decision circuit 8, 8b after comparator 8 produces a chopper signal 17 to produce a disconnection signal upon occurrence of line-disconnection in winding 21 or 22.

Abstract: Apparatus for driving a three-phase compressor assembly from a single-phase electrical power supply having first and second power lines, said three-phase compressor assembly comprising a compressor having a rotatable shaft, an electrical motor having a rotatable shaft coupled to the rotatable shaft of the compressor, the electrical motor having at least first, second and third motor windings and having at least first, second and third terminals connected to the first, second and third windings, means adapted to connect the first and second power lines of the single-phase power supply to the first and second terminals and a torque augmentation circuit for injecting current into the third terminal and including a capacitor and an electrical component in series with the capacitor, said electrical component having resistive characteristics and having means for essentially interrupting the current being injected into the third terminal.

Abstract: In a resonant motor system, an electrical motor having a stator with one or more windings, a rotor which may or may not be wound, and an air gap between the stator and the rotor for storing magnetic energy such that the motor exhibits a definite electrical inductance may be deployed with a drive combination including a capacitance connected in series with the inductance of the motor to form an LCR circuit therewith. Phased provision of DC power to the LCR circuit causes the circuit to oscillate, which excites the motor. The DC power is provided in synchronism with the rotation of the rotor in order to maximize torque produced by the motor.

Abstract: An induction generator having one or more energy windings and one or more auxiliary windings where the auxiliary windings have fixed and switched capacitors which are used to control the induction generator output under variable load conditions. The auxiliary windings are electrically and magnetically isolated from the energy windings. The fixed capacitors are used under minimum load condition and the switched capacitors added in response to controls signals. The control signals are determined by analyzing the load voltage and current and the voltage across the particular capacitor being added. The induction generator is included in systems where the generator is rotationally driven by an engine and which couples the energy windings to a power grid and/or to a variable load. The engine may also employ a controller that receives the load current and voltage signals to determine engine speed.

Abstract: A system and method for controlling a variable capacity compressor driven by a motor. Preferably, said system and method are used with a reversible, two-stage compressor motor. In one embodiment, the method includes, for example, operating the variable capacity compressor at a first capacity to satisfy a demand for heating or cooling; detecting a change in the demand for heating or cooling; operating the variable capacity compressor at a second, different capacity based on the detected change in demand; detecting an operating parameter that can indicate an opportunity to increase compressor efficiency when the compressor is operating at a given capacity; and varying the torque applied by the motor when the detected operating parameter indicates an opportunity to increase efficiency of the compressor by varying the torque.

Abstract: A motor start capacitor assembly for providing an enclosure for a motor start capacitor and a thermistor electrically connected in series. The enclosure is constructed of a low temperature plastic case and cap with a high temperature plastic core for supporting the thermistor within the low temperature plastic case. The core holds the thermistor in a longitudinal orientation. The core and thermistor and related contacts are assembled without rivets or other fasteners.

Abstract: An energy efficient low-power integral electronically commutated fan motor and control circuit assembly mounted on a circuit board for use in refrigerators utilizing a Hall sensor to provide positional control signals for sequential energization of the windings with the Hall sensor energization being pulsed, and the motor stator windings energized only during a portion of the period, when rotational torque produced by the energization is greatest in order to reduce the power input to the assembly. Integrally molded multi-function components including the coil bobbin, ground pin, Hall sensor holder, motor bearing oil well covers, and assembly housing provide positioning, support, and securing assistance along with electrical and magnetic operative connections and positioning.

Abstract: An improved induction motor having at least one capacitive element electrically connected in parallel with and tapped to each phase of a delta- or wye-wound stator winding such that the capacitive elements are alternately charged or discharged during operation, thereby storing energy from and releasing energy to the windings. This alternate energy storage and release assists in controlling the level of magnetic core saturation and increasing motor efficiency under all operating conditions due to reduced hysteresis and eddy current losses. Motor starting or inrush current is also substantially reduced using this arrangement. In one embodiment, variable capacitors and switch elements are used to provide the ability to dynamically “tune” the motor winding for optimal efficiency.

Abstract: A three phase AC motor which rotates at the synchronous speed determined by the number of poles of its main stator winding and the frequency of the AC input to it, which does not need any exciter machine or brushes to provide its DC field current, but has an internal, but independently adjustable excitation system to supply its field current. The internal excitation system consists of an auxiliary winding on the stator which is additional to the main power winding, another auxiliary winding on the rotor besides the main DC field winding, a diode rectifier circuit on the rotor from which the DC field current is supplied by rectification of the induced currents in the rotor auxiliary field. The field current adjustment can be made by adjustment of the input to the stator auxiliary winding. This can be done independently by eliminating any magnetic coupling between the main and auxiliary circuits.

Abstract: For a three-winding motor, a starting capacitor bank provides balanced currents in the windings, a high starting torque, and unity power-factor current in the single-phase supply line. A run-capacitor bank provides full-load balanced currents and a leading power-factor in the single-phase supply line. The method is applicable to a star or wye winding connection, to a delta winding connection, and to a Semihex.TM. winding connection.

Abstract: An improved method of starting three-phase and three-winding induction motors from a single phase supply reconfigures the 6 accessible windings of a standard induction motor into first an optimal starting configuration which, for example, may reduce starting torque or starting current and then an optimal run configuration. One example of a run configuration is a normal delta along with an inverted delta; another example is a (voltage phasor half-hexagon) run configuration where the windings are all series connected with 120.degree. phase differences.

Abstract: A capacitively powered motor having a power switching circuit adapted to be connected between a power source and its winding for selectively energizing the winding to generate a magnetic field which causes a rotating assembly to rotate. A position sensing circuit provides a position signal representative of the position of the rotating assembly and a commutating circuit controls the power switching circuit to commutate the power switching circuit at a commutating angle and at a substantially constant duty cycle to achieve a desired rotating speed of the rotating assembly. The commutating circuit varies the commutating angle in response to the position signal to maintain the substantially constant rotating speed of the rotating assembly. As result, the efficiency of the motor is varied to maintain the substantially constant rotating speed.

Abstract: Noise suppression system for a relay-switched windshield wiper, wherein reversal of current to a motor driving the wiper causes the motor to reverse. Filters contained within the motor, together with filters and shielding located external to the motor, suppress rf emissions.

Abstract: The invention relates to a single-phase induction motor comprising a main winding, an auxiliary winding which is arranged so that an electrical angle of the auxiliary winding is different from that of the main winding, a plurality of driving capacitors which are connected to the auxiliary winding, a relay for controlling on/off of the driving capacitor in response to the driving load, and a rotor having apertures on the gap side of the slots. The invention further relates to a rotor assembling apparatus comprising a bush to which a rotor core assembly is inserted for die-casting, wherein a clearance between said bush and said rotor core assembly is narrower to the extent that said rotor core assembly can be taken out after die casting; and a core band having a clearance between the core band and the bush in the circumferential direction of said bush, said core band is engaged into said bush so that movement in the axis direction is restricted.

Abstract: The single-phase induction motor has a starting device which is activated during the start-up phase of the motor and exposes at least a part of the motor coil to a voltage which changes temporarily, the average value of the voltage formed during one period of oscillation not being equal to zero.

Abstract: An auxiliary capacitance starting device is connected by only two wires to a capacitor start-induction run (CSIR) or permanent split capacitor (PSC) motor. The device includes an auxiliary start capacitor and an electro-mechanical switching relay that has a current sensing coil wound over a voltage sensing coil and a set of normally closed contacts. The relay is energized first by a current level (amperage) and then latches into an energized mode by voltage, necessarily in that order. The auxiliary start capacitor is electrically connected to the motor circuit in parallel to the start and run winding by two non-polarized leads and in series with the current sensing coil. The voltage sensing coil is connected across the normally closed contacts and senses no voltage as long as the contacts are closed.

Abstract: A starting device for single phase induction motors having a start capacitor is effective to disconnect the start capacitor at a desired motor speed in response to a specific phase relationship between the voltage across the main winding and the voltage across the start winding. The specific phase relationship is a condition wherein a phase angle defined by the phase relationship reverses from a decreasing value to an increasing value.

Abstract: A motor control system for a multi-speed electric motor electrically excited by a power source having at least two terminals. The motor controller system includes a switching device electrically connected to the terminals of the power source for alternating current flow from the power source, a first speed circuit, and a second speed circuit. The first speed circuit includes a first speed primary winding electrically connected to the switching device, a first speed secondary winding electrically connected to the first speed primary winding, a start capacitor electrically connected to the first speed secondary winding, and start relay electrically connected to the start capacitor. The second speed circuit includes a second speed primary winding which is connected to the switching device.

Abstract: Disclosed is a circuit for controlling the load of an asynchronous motor (11), the circuit comprising two capacitors (19, 20), one of which (20) can be connected, by means of a switch (70), in parallel with the other (19). Control is provided by a current sensor (30) and a voltage sensor (40), whose signals (S.sub.1, S.sub.2) are compared by a comparator (25). Depending on the relative size of the signals (S.sub.1, S.sub.2) a switch control unit (60) with relaxation hysteresis characteristics switches the switch (70) on or off. The circuit is simple, operates independently of the mains voltage (U) being used and its switch point can be adjusted by means of the current sensor (30).

Abstract: The centrifugal pump unit has a split tube motor in the form of a single phase induction motor with at least one power winding and a starting winding accommodated in a split tube casing. For the purpose of unblocking the rotor, a rectifier element is provided, which is able to be connected in parallel or in series with at least a part of a starter or power winding. The average torque produced by the motor when in its unjamming phase is always in the same direction, so that the pump will commence rotating in the correct direction when unjammed. The rectifier element may be connected in every time the pump unit is started, possibly for a predetermined time, or may alternatively be connected in only when jamming occurs.

Abstract: An induction motor speed control apparatus and method wherein various capacitors are switched in series with the auxiliary winding of an induction motor and, during such switching, the power source is disconnected from the main and auxiliary windings and the in-use capacitors are momentarily connected to the main winding to form a closed-loop discharge path through the main and auxiliary windings.

Abstract: An auxiliary capacitance starting device is connected by only two wires to a permanent split capacitor motor. The device includes an auxiliary start capacitor and a control relay which has a set of normally closed contacts, a coil, and a resistor. The auxiliary start capacitor and the normally closed contacts are connected in series and the coil and resistor are connected in series and in parallel with the auxiliary start capacitor and contacts. The free ends of two non-polarized wire leads are interchangeably electrically connected to the start and run windings or the run capacitor of the motor to place the circuit in parallel with the start and run windings or the run capacitor such that the relay coil means becomes energized upon detection of voltage representing full motor speed to open the contacts and break the electrical connection between the auxiliary start capacitor and the start and run windings.

Abstract: A multiple speed alternating current motor is disclosed for operation from a source of single phase alternating current power. For high speed operation, first and second windings are supplied with operating power through a multiple position switch. These windings are electrically angularly displaced from one another by 90.degree. on the stator core and are inductively coupled to the rotor of the motor. Maximum starting torque and maximum speed operation of the motor is provided in this condition of operation. When the switch is operated to a low speed position, the impedence of the second winding is increased.

Abstract: An auxiliary capacitance starting device is connected by only two wires to a permanent split capacitor motor. The device includes an auxiliary capacitor and a potential relay which has a set of normally closed contacts and a relay coil. The auxiliary capacitor and the normally closed contacts are connected in series and the relay coil is connected in parallel therewith. The free ends of the two non-polarized wire leads are interchangeably electrically connected to the start and run windings or the run capacitor of the motor to place the circuit in parallel with the start and run windings or the run capacitor such that the relay coil means becomes energized upon detection of voltage representing full motor speed to open the contacts and break the electrical connection between the auxiliary capacitor and the start and run windings.

Abstract: A sationary rotatable anode (42) of an x-ray tube (10) is electrically connected to a high speed starter (24). The starter (24) includes an inductive rotor (44) connected to the anode (42), a main stator winding (50) and an auxiliary stator winding (52). The rotor (44) is driven by a power drive circuit (26) which is part of the starter (24). A main capacitor (64) is placed in series with the main winding for reducing its inductance. An auxiliary capacitor (66) is placed in series with the auxiliary winding for maintaining a selective impedence. A control circuit (90) is included in the starter (24) to control the main current and auxiliary current so that as the rotation of the rotor (44) increases, the control circuit (90) lowers the frequency of the main current and the auxiliary current passing to the main and auxiliary windings.

Abstract: A capacitor-start capacitor-run single phase AC induction motor control starting circuit is provided which minimizes first cycle current spiking magnitude, and also minimizes cycle to cycle current spiking magnitude, without a choke or inductor in the loop containing the run capacitor, start capacitor and start switch. The first cycle current spiking problem is solved by controlling when the start switch may be turned on at initiation of the starting mode in relation to the AC cycle, to permit turn-on of the start switch only within a known or predictable range of voltage differential between the run and start capacitors. The cycle to cycle current spiking problem is solved by proper phasing of gate current, and supplying gate current to the start switch in phase with the voltage across the run capacitor and out of phase with the current through the series connected start switch and start capacitor.

Abstract: An electromagnetic induction machine having inductively coupled primary, secondary and tertiary branch windings. The exciting current of the primary branch is transformed or reflected, via the inductive coupling, to an electrically separate secondary or tertiary branch. This reflected current in the isolated branch is sustained by connecting a capacitive load impedance to it. Thus, a floating parallel resonant circuit is formed which supplies the needed reactive component in lieu of the primary branch. Different winding techniques are then incorporated in the separate branches to maximize the available winding space and provide improved operating or performance characteristics.

Abstract: A series resonant capacitor motor is operated from a source of single phase alternating current power, and the start and run windings are wound on the stator electrically angularly displaced from one another by 90.degree.. The run winding is of heavy wire, and it is connected in series with a capacitor having a high capacitance to the source of alternating current power. The start winding is connected in parallel with the series connected run winding and capacitor. During the full load and no load running conditions of operation of the motor, substantially all of the current passes through the run winding and capacitor with little or no current flowing through the start winding. The motor exhibits improved starting torque, and an additional switched starting capacitor can be connected in parallel with the series resonant capacitor to produce high starting torque.

Abstract: A self-excited induction motor variable speed drive using a known self-excitation method in which a capacitor is connected in parallel with the motor. Power is supplied by a supply convertor, a D.C. link and a motor convertor, the latter running at the motor frequency. The motor convertor includes a current bypass switching circuit comprising a capacitor bank connected to the motor terminals and to a neutral point between a pair of thyristors connected across the D.C. link.

Abstract: A motor starting control circuit is provided with an auxiliary switch (100), including a triac (102) and series resistor (114), connected across the start capacitor (5) for quickly discharging the start capacitor (5) upon disconnection of the start capacitor (5) from the AC source (4). This enables a lower rated start switch (6) by eliminating extra voltage thereacross caused by an otherwise charged start capacitor (5).

Abstract: Apparatus and method for reducing the voltage drop in an electrical power distribution system during the starting of a multi-phase induction motor having stator windings supplied therefrom and for decreasing the loss in starting torque of the motor. A capacitor is provided for direct connection across each stator phase winding of the motor. These are electrically connected to the stator windings substantially simultaneously with the motor being supplied with power from the distribution system. These capacitors have a capacitance which exceeds that required to raise the no-load power factor of the motor to unity at running speed but is less than that which will correct the power factor of the motor to unity under locked rotor conditions. Preferably these capacitors are electrolytic-type capacitors and have a capacitance which will reduce the motor starting current by at least approximately 30%.

Abstract: An electric current motor is operated from a single phase of alternating current power source, and functions with low surge operation at motor start. The motor includes first and second windings of substantially the same wire size angularly displaced from one another 90.degree. electrical on a stator core and inductively coupled to a rotor. A capacitor is connected in parallel with one of the windings to form an LC resonant circuit at the operating frequency of the motor. A second starting capacitor is connected in series with a switch in parallel with the first capacitor. The switch is normally closed during starting of the motor and is opened during normal load conditions.

Abstract: A new assembly for a capacitor-run submersible motor-pump. The assembly has a built-in starting capacitor and a built-in switch associated with the starting capacitor. A running capacitor is located external to the assembly. With this arrangement, the assembly has only four terminals including a ground terminal connected to the frame of the motor. Thus, a four-conductor cable, i.e. the most commonly used cable, can be used to connect the assembly to an electric distribution panel. The switch is preferably of a centrifugal type triggered at a predetermined speed of the motor to cut the starting capacitor out of the circuit. The assembly is as compact as a conventional capacitor-start motor assembly.

Abstract: A stall detection method for electric induction motors and apparatus utilized the stator current and voltage phase difference as proportional to percentage synchronous motor speed, and detects a stall condition from this speed as a parameter of motor movement. The invention includes differentiating the phase difference to obtain motor acceleration as a parameter potentially indicative on its own, or in conjunction with phase difference, of a motor stall condition.

Abstract: Single-speed, three-phase motors and two-speed, three-phase motors are started and run by a static phase converter which comprises a timing circuit, adjustable for a starting interval, and a switching device which configures a plurality of capacitors, with respect to motor windings, so that a starting capacitance and a running capacitance are connected during a starting mode for a high-torque condition, and, thereafter, the run capacitance is connected for running the motor.