Abstract: Problems associated with delta motors and motor controllers being subjected to swapped lead conditions as well as with time consuming troubleshooting are eliminated in a motor controller that automatically changes firing circuit timing for proper operation of the delta motor when it detects swapped lead condition that occurs during the installation process.

Abstract: A method of operating an electric three-phase machine with a polyphase winding arrangement in a vehicle. The phases of the winding arrangement are connected to a vehicle network with the aid of power converters and the winding arrangements are interconnected in a first method of connection for motor operation and interconnected in a second method of connection for generator operation. Switching over from one method of connection to the other is performed at an instant at which the three-phase machine changes from the state of picking up torque to outputting torque, or from the state of outputting torque to picking up torque.

Abstract: A chopping energization control device is made up of a first switching element interposed between one end of a load and one terminal of a power supply, a second switching element interposed between the other end of the load and the other terminal of the power supply, a signal generation device for generating an energization indication signal which makes the first switching element and the second switching element conductive in order to establish a chopping energization control of the load, and a control device for giving a delay, in response to the energization indication signal, between when the first switching element is made to be conductive and when the second switching element is made to be conductive.

Abstract: A reactor (32) and a switch (35) are interposed in parallel between U-phase, V-phase and W-phase on a power source side (31) and U, V and W terminals on a motor side (33). A changeover switch )37) is interposed between Z, X and Y terminals on the motor side (33) and the U, V and W terminals on the motor side (33). When the switch (35) is set to OFF, the changeover switch (37) is set to ON, and the switch (35) is set up so as to interconnect Z, X and Y terminals, windings of the motor are set up in the form of Y-connection, so that the motor and a power source are connected directly to each other. On the other hand, when the changeover switch (37) is switched over to OFF, and the switch (35) is set up so as to interconnect Z, X and Y terminals to the U, V and W terminals, the windings of the motor are set up in the form of &Dgr;-connection, so that the motor and the power source are connected together through the reactor (32).

Abstract: Problems associated with maintaining a large inventory of multiple types of motor controllers designed to accommodate a single motor type are eliminated in a motor controller that automatically senses if it connected to a delta motor or a wye motor and configures itself for operation in a compatible mode.

Abstract: An induction motor as driving apparatus includes two stators in which two rotor cores each formed in a squirrel cage type are rotatably mounted on a common rotary axis; two stators which respectively surround the two rotors and on which stator windings are respectively wound; and a switching device which supplies power by sequentially switching between one side of either the one stator winding or the other stator winding and both the sides of the two stator windings. Starting characteristics and operation characteristics of an induction motor are improved thereby enlarging applications of the induction motor, enhancing operation efficiency, and reducing power consumption.

Abstract: An air compressor includes a stator, which includes an inlet and an outlet and defines a substantially cylindrical bore, and a rotor eccentrically rotatably mounted in the bore. The rotor is connected to be rotated by a three-phase asynchronous electric motor of pole amplitude modulated type which is switchable between low speed six pole operation and high speed four pole operation under the control of a controller. A pressure sensor communicates with the compressor outlet and is connected to the controller which is arranged to produce a first signal when the compressor discharge pressure falls below a first threshold value and a second signal when this pressure rises above a second threshold value.

Abstract: A BEMF detector and method detect the BEMF of a three-phase motor using a fully differential detection system. The motor has a first coil coupled between a first coil tap and a center tap, a second coil coupled between a second coil tap and the center tap, and a third coil coupled between a third coil tap and the center tap. The BEMF detector includes a differential amplifier having first and second inputs and first and second outputs, with the first input being coupled to one of the coil taps and the second input being coupled to the center tap. The BEMF detector also includes a comparator having first and second inputs coupled respectively to the first and second outputs of the differential amplifier and an output at which a BEMF signal is produced that is related to the BEMF of the motor. The differential amplifier may be part of an anti-alias filter structured to fix to a known stable value a common mode at the outputs of the differential amplifier.

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: The invention provides a method for controlling a brushless motor, with windings connected in star (`wye`) formation, including the steps of periodically applying a supply voltage between first and second windings, detecting the presence of a current in a third winding, and an instant of cessation of that current, monitoring the value of a back emf induced in the third winding and detecting a zero crossing point of the back emf, timing a predetermined delay from the zero crossing point, and after the end of the delay, applying the supply voltage to other windings. The invention also provides a method for use with motors having windings connected in delta formation.

Abstract: An induction motor as driving apparatus includes two stators in which two rotor cores each formed in a squirrel cage type are rotatably mounted on a common rotary axis; two stators which respectively surround the two rotors and on which stator windings are respectively wound; and a switching device which supplies power by sequentially switching between one side of either the one stator winding or the other stator winding and both the sides of the two stator windings. Starting characteristics and operation characteristics of an induction motor are improved thereby enlarging applications of the induction motor, enhancing operation efficiency, and reducing power consumption.

Abstract: A controller is provided for use with electric motors which will achieve a two mode motor operation. In this operation, a first mode is utilized having a torque configuration thus more efficiently providing high torque outputs from the motor. However, a second configuration is also used which more efficiently accommodates high speed operations albeit at the expense of some output torque. The system accomplishes this two mode operation in a low cost manner so as to minimize the overall cost of products or devices utilizing this power control system.

Abstract: A method and apparatus for controlling an induction motor having at least high speed windings and reduced speed windings divides the reduced speed windings into first and second portions. The first and second portions of the reduced speed windings are electrically connected in series and a voltage is applied to the first and second portions of the reduced speed windings when it is desired to operate the induction motor at a reduced speed. The first and second portions of the reduced speed windings are electrically disconnected and a voltage is applied to the high speed windings when it is desired to operate the induction motor at a high speed. The induction motor has three sets of windings extending from a middle region, each set of windings having an inner winding toward the middle region and an outer winding away from the middle region.

Abstract: Dynamic operation of a brushless N-phase DC motor results in a high torque constant (Kt) line-to-line phase configuration during spindle motor power-up, and in a lower effective Kt configuration once normal run speed operation is attained. When the spindle motor is rotating below a predetermined run speed, drive transistors coupled to the motor phases cause at least two phases to be series-coupled between the source of operating voltage and ground. This ensures a large initial torque because the Kt contribution of each series-coupled phase is combined vectorially. Once run speed is achieved, effective Kt is lowered by causing the drive transistors to energize but a single phase, reconfiguring the spindle motor for line-to-neutral operation. So doing reduces the effective back electromagnetic force, permitting sufficient run current from a given magnitude operating voltage source.

Abstract: A motor drive system, and method for operating the same, which includes current mirror load current sensing, is disclosed. Sensed current is used in the well known manner to control the low side drive of the motor. The disclosed motor system operates in a bipolar mode on startup, and in a unipolar mode during full speed operation. In unipolar mode, a current mirror transistor is provided to sense the load current through the center tap drive transistor in a continuous manner. Ripple in the sensed current is avoided, as the center tap drive transistor is not commutated during motor operation in unipolar mode. In bipolar mode, current mirrors are provided for both of the high side and low side drive transistors in each leg, with the currents summed for each coil at a sum node, and with the summed current applied to a cumulative sum node; the summed current never drops to zero, as only one drive transistor changes in each phase change in the commutation sequence.

Abstract: A brushless direct current motor includes a permanent magnet mounted to a rotor and a set of commutated stator windings. The motor further includes a circuit for changeably connecting the set of stator windings to operate in a first electrical configuration or a second electrical configuration and a circuit for commutating the set of stator windings when connected in the first electrical configuration or the second electrical configuration.

Abstract: The present invention is applicable to any a.c. electromagnetic reduction device which is used to change voltage or current levels or to transfer energy between mechanical and electrical systems and includes, for each phase, a combined pair of windings which are conductively and inductively dependent. The dominant winding of each combined pair is electrically connected to an input/output phase, while the reflux winding of each pair is electrically connected in additive or subtractive series with the dominant winding by means of a variable capacitive reactance. The capacitive reactance is then adjusted to minimize the net reactive factor of the coupled windings and the net reflected impedance of the input/output circuitry.

Abstract: A multiphase load control system has switches in electrical series within each of several split sources of phase voltage. In each phase of one implementation, two contactor poles are in series between split sections of a secondary winding of a transformer. The contactor poles are part of one or more contactor units, each of which can have a voltage rating significantly less than the phase voltage provided by the system.

Abstract: An apparatus and method are provided for controlling a reduced voltage motor starter, which transitions from a reduced voltage configuration to a full voltage configuration, to start a large horsepower electric motor for driving a machine.

Abstract: A method and apparatus for operating a polyphase dc motor selectively in dual-coil or uni-coil commutation modes. The motor has a plurality of "Y" connected driving coils connected together at a center tap. Each driving coil has an input node at an end opposite the center tap, and is driven by a switch pair. Each switch pair is arranged for connection in series across a power supply voltage, and has a node between each switch connected to a respective one of the coil input nodes. An additional pair of switches are provided for connection in series across the power supply with a connection node between each switch connected to the center tap. A circuit is provided to operate the switches to cause a driving current to be passed between sequentially selected pairs of the driving coils for an initial start-up time.

Abstract: An alternating current generator having a first Y-form three-phase connecting circuit including three first windings connected with each other in a Y-form, a first rectifying circuit for rectifying currents output from output terminals of the three first windings, a second Y-form three-phase connecting circuit including three second windings connected with each other in a Y-form, and a second rectifying circuit for rectifying currents outputted from output terminals of the three second windings. The three first windings are inserted in slots of a stator core so that the three first windings have phase differences of approximately 120 degrees from each other.

Abstract: A stator coil of a rotary electric machine includes a three-phase Y-form connection circuit including first windings Y1, Y2 and Y3, which are connected in Y-form, and a three-phase delta-form connection circuit including second windings .increment.x3, .increment.y3 and .increment.z3 which are connected in delta-form, wherein the second windings .increment.x3, .increment.y3 and .increment.z3 are sequentially inserted in slots of a stator core to have a phase difference of 120.degree. therebetween, and each of the first windings Y1, Y2 and Y3 is divided into two windings, and the divided first windings are separately inserted in the slots, in which the second windings .increment.x3, .increment.y3 and .increment.z3 have been inserted, so that the resultant composite voltage vector of each pair of the divided first windings is shifted by 30.degree. in phase from the voltage vector of one of the second windings .increment.x3, .increment.y3 and .increment.z3.

Abstract: An electrical apparatus, comprises a bridge circuit having a plurality of rectifier legs electrically coupled in parallel. Each of the rectifier legs comprises a first and a second rectifier coupled in series and having an input node therebetween. The electrical apparatus further comprises a switch, having a control input, a power input, and a power output, coupled in parallel with the bridge circuit, and a controller having a control output coupled to the control input of the switch for regulating the opening and closing of the switch. When the bridge/switch element is coupled to the disassociated neutral terminals of a wye wound electrical device, the controller modulates the opening and closing of the switch to provide an current controlled soft start of the device, as well as continued motor drive capability, including acceleration and breaking of the device.

Abstract: A low-cost means to drive a three-phase motor from a DC energy source. The low cost is achieved by requiring only two inverter circuits instead of the conventional three inverter circuits. The third input phase to the motor is grounded. Balanced three-phase power is developed across the three stator coils of the motor, resulting in normal three-phase operation, including control of rotational direction. This is accomplished by appropriately selecting the phase angle of the two active phases.

Abstract: A control method and apparatus for actuating an induction motor which is capable of generating a sufficiently large output in a wide speed region. In such an induction motor, each of Y-connection phase windings of the induction motor is divided into two split windings 5t and 3t at a predetermined split ratio (for example, 5:3). When a rotational speed of the induction motor is in a low speed region, only the changeover switch MC2 is turned on to supply exciting current to both of the split windings 5t and 3t. When the rotational speed of the induction motor is in a middle speed region, only the changeover switch MC3 is turned on to exclusively supply exciting current to the split windings 5t. Furthermore, when the rotational speed of the induction motor is in a high speed region, only the changeover switch MC1 is turned on to exclusively supply exciting current to the split windings 3t.

Abstract: A switched stepping motor for use in a computer-controlled processing system, the motor being capable AC or DC operation in a continuous or stepwise manner for completing a variety of operations such as lathe cutting, drilling, planning, milling, abrading, and boring.

Abstract: An alternating current (AC) motor system includes an AC motor having a rotor and a stator with the rotor having a plurality of air passes for passing cooling air and the stator having end windings extending from each end. An air deflector is coupled to one end of the rotor and has a generally curved configuration for directing cooling air exiting the air passages into a generally radial flow direction and onto the stator end windings. The stator end windings comprise turns of a plurality of electrical conductors forming the stator winding circuits which are wound to form a plurality of phase windings. Controllable switches are connected to the winding circuits for coupling the phase windings into either a parallel or series circuit arrangement. The system is responsive to motor speed and operating state for selectively switching the windings between the series and parallel electrical circuit arrangements.

Abstract: A three-phase induction motor is driven efficiently from a single-phase power supply by reconnecting the motor windings and using two or more capacitors to provide balanced currents and voltages in the windings at preselected values of power. A similar method is used to drive a three-terminal conventional motor from a single-phase supply by using a tapped autotransformer with two different voltages and two different capacitors to excite the third motor terminal. Capacitor switching in all embodiments is controlled by feedback from the voltage across the winding with capacitor excitation.

Abstract: A synchronous motor includes a unitary rotor, a first stator, a second stator and phase-changing switches. The unitary rotor has a first rotor portion formed by a first permanent magnet and a second rotor portion formed by a second permanent magnet and an induction type rotor and these first and second rotor portions are mounted on a common rotary axle with a predetermined space provided therebetween. The first stator faces the first rotor portion for producing a first rotating magnetic field. The second stator faces the second rotor portion for producing a second rotating magnetic field and is disposed such that, at the starting operation, the attracting action or the repelling action produced between the first rotating magnetic field and the first permanent magnet is canceled by the repelling action or the attracting action produced between the second rotating magnetic field and the permanent magnetic field.

Abstract: In the alternating current generator for vehicle, an armature coil comprises a Y-connected first three-phase armature coil and a delta-connected second three-phase armature coil whose phase windings are inserted into same slots respectively. Each of the three-phase armature windings is provided with rectifying means for converting respective a.c. output into a direct current. The direct currents are summed to provide an output of the generator. It is effective to use a plurality of rotary magnet poles provided on a shaft of the generator for a compact a.c. generator in which the radial dimension of the rotary magnet poles is reduced.

Abstract: An electric machine system includes a number of improvements that heighten the performance provided by the system. In particular, the electric machine system may include bypass capacitors for filtering and storage. Further, the electric machine system may include bidirectional power switches for coupling different phase current signals to respective windings in the electric machine system. These switches control which phase signals are connected to the respective windings of the electric machine system.

Abstract: An electric machine system includes a resonant switching system for selecting a resonant frequency of at least a portion of the circuit of the system. The electric machine system includes a first pair of windings for generating force to actuate a moving body and a second pair of windings for exciting the first pair of windings. The resonant switching system includes a resonant inductor and a resonant capacitor. The carrier signal used to excite one of the pairs of windings may have a frequency that is substantially equal to the resonant frequency of the circuit. Preferably, the air gap magnetic flux distribution for the pairs of windings are substantially alike. The electric machine system may employ a rotating body or alternatively may employ a linearly actuating body.

Abstract: A wye-delta open transition motor starter provided with a leading phase monitor and a method of using the same such that transient currents during the open transition are limited to acceptable magnitudes.

Abstract: Low rotational speed characteristics of a three-phase induction motor driven by a PWM inverter are improved by rapid .DELTA.-Y connection switching by semiconductor switches (1, 2, 3, 4, 5), for example, TRIAC's.

Abstract: An induction motor, including a single rotor formed in one-piece and first and second stators disposed side by side, has a phase changing device for varying the phase difference between the rotational magnetic field generated by the first stator and that generated by the second stator. The phase changing device comprises at least first and second short-circuiting switches for short-circuiting or disconnecting the series-junction nodes of the stator windings. The first switching produces a configuration intermediate to series delta and parallel Y (Wye), and the second completes the transformation from delta to Y. The motor presents three different torque curves suitable for starting operation, intermediate speed operation and normal or steady-state operation by the switching operation of the first- and second-switches.

Abstract: Provided is a spindle drive control apparatus which is provided with a single three-phase spindle motor (60) for rotatingly driving a spindle (50) of a machine tool and a solenoid relay (70) for switching the phase windings (U, V, W) of the motor between a delta (.DELTA.) and star (Y) state and which switches the phase windings to the delta connection when rotating the spindle (50) at high speed for heavy duty cutting work and switches to the star connection for generating the high torque when rotating at a superlow speed (for example, 0.5 rpm) for contouring machining work etc. In this way, it becomes possible to handle the machining work performed in the past with two types of motor by using just a single motor, thus contributing to reduced costs.

Abstract: A starting system for a rotary dynamoelectric converter is disclosed. The converter is of the type having three sets of windings wired in either delta or wye configuration. Each set of windings consists of two coils normally connected in parallel within the respective winding, and the converter has three leads connected to the delta or wye configurations. Two of the leads are to be connected to a source of single-phase, alternating current, and a run capacitor is connected between one of the first two leads and the third lead, such that three-phase current can be drawn from the three leads when the dynamoelectric converter is running at its normal operating speed. The starting system comprises a mechanism for connecting the two coils in each respective winding in series with each other when single-phase current is initially connected to the first two leads to start the converter.

Abstract: An induction motor including a single rotor formed in one-piece and first and second stators disposed side by side has a phase changing device for varying the phase difference between the rotational magnetic field generated by the first stator and that generated by the second stator. The phase changing device comprises a first-connection changing switch for making the interconnection of respective stator windings of the stators the first series delta-connection in which the phase difference is 0.degree. when it is in its closed-state and a second-connection changing switch for making the respective stator windings the second series data-connection in which the phase difference is 120.degree. when it is in its closed-state. When both the first- and second-connection changing switches are closed, the interconnection of the stator windings becomes a parallel Y (or star)-connection in which the phase difference produced is 60.degree..

Abstract: The invention relates to a motor output changeover control apparatus used for the spindle motor of machine tools. Conventionally, since a constant output over a wide range is realized by gears, a spindle motor is constituted by a single winding. The amount of heat produced by the winding is great, and a speed-change mechanism employing the gears is large in size.With the motor output changeover control apparatus of the invention, output characteristics over a wide range from high to low speeds is stabilized by changing over the connection of the power lines of an AC motor.

Abstract: The drive arrangement suitable especially for a hoist mechanism comprises a pole-changing two-speed three-phase motor which is united into one construction unit with a friction brake which can be released by an electromagnet. The two three-phase field windings dimensioned for different pole numbers are connected in star circuit arrangement and have star points conducted out at the motor terminal box of the three-phase motor. The electromagnet of the friction brake is connected through a rectifier circuit arrangement to the star points and when the three-phase motor is switched on is energized by the differential voltage then occurring between the two star points for the release of the friction brake.

Abstract: In the operation of an A.C. motor by switching the number of poles of the motor or the power sources of different frequencies, switching operating circuit is constructed to automatically switch so that the motor does not overheat by the above-described switching. Thus, the energy of the power sources can be saved.

Abstract: A three phase two-pole induction motor includes a three phase winding wound as a two-pole winding with an effective full pitch wound winding connected in a double delta connection. Each pole group includes a plurality of coils wound as a concentric winding or as a short pitch lap wound equivalent winding. A 36 slot stator is illustrated and includes each phase winding wound with 2 coil units each having 2 coil groups. Each coil group has 3 concentric coils and in the illustrated concentric winding the one phase winding has one group with coil sides in slots 1-3 and 16-18 and the second group in slots 19-21 and 34-36. The next phase winding has similar coils in slots 4-6 and 25-27 and in slots 7-9 and 22-24. The third phase winding has similar coils in slots 10-12 and 31-33 and in slots 13-15 and 29-30. The coil sides of each of the two groups are connected to form a full pitch winding.

Abstract: An ac drive in which the three phase ac current produced by a current controlled inverter is applied to the stator winding of a synchronous or induction motor through an autotransformer equipped with a neutral shorting switch. For starting from zero speed and operation at very low speeds below the speed at which the autotransformer could provide adequate volt-seconds for operation of the motor, the neutral shorting switch is opened so that the current is applied essentially directly to the stator. At normal and high speeds, the neutral shorting switch is closed so that the voltage to the motor stator is increased by the turns ratio of the autotransformer thereby increasing the speed range of the motor. By providing a number of sets of taps on the autotransformer each with a neutral shorting switch, the ac drive mimics the characteristics of a drive with a multi-ratio gear box.

Abstract: A system for converting variable frequency multiple phase current into multiple phase current of constant frequency with a neutral having a multiple phase inverter with a neutral (N) is disclosed. A first input (34) is connected to the multiple phase inverter for receiving pulses of a positive polarity. A second input (36) is connected to the multiple phase inverter for receiving pulses of a negative polarity. A variable frequency multiple phase source (12, 14 and 16) of alternating current applies current to a multiple phase transformer (80, 142 and 180). Current from the transformer is applied to a full-wave rectifier (96) which has a first group of diodes (112) which applies the positive pulses to the input (34). A second group of diodes (116) applies the negative pulses to the input (36). The ripple frequency f.sub.

Abstract: An inverter driving method for has an arrangement polyphase induction motor, for altering a plurality of winding connections of the motor and a storage arrangement for a plurality of motor control constant groups preset corresponding to the respective winding connections so as to perform optimal vector control. When the classification of the winding connection is selected, one set of motor control constant groups corresponding to the winding connection is read out of the storage arrangement and applied to a control unit of the induction motor as control constants.

Abstract: A switchable arrangement for at least three different operating states is made possible with a minimum number of external winding terminals and a switching device as simple as possible, and current heating of the entire winding as uniform as possible. In the starting-up stages with free adaptation of the inrush current reduction and far-reaching avoidance of disturbing field harmonics is provided. The machine impedance is increased over the normal operating stage by the provision that in the normal operating stage the parallel connected winding branches assigned to a leg are separated and are assigned to different branches, remain without current in part in individual stages and/or are operated with partly different direction of excitation.

Abstract: The present invention provides a method for starting motors by harmonics for synchronous motors, wound-rotor and cage-rotor asynchronous motors started thereby. During the starting period, according to the present invention, the connection of the stator winding is changed so as to create some very strong harmonic fields. The harmonic fields are associated with the rotor windings and are used to improve the starting performance of the motor. The three motors all have large starting torque, small starting current and can be started by direct-on-line. The wound-rotor asynchronous motor has no brushes or, slip rings on the rotor and there is no electric contact thereby increasing the reliablity of starting and running. The running efficiency is superior to the cage-rotor asynchronous motor.

Abstract: Method and apparatus for matching the power output of a high slip motor to the demand requirement of a pumpjack unit. The stators of the high slip motor are automatically connected in various different configurations to provide the optimum torque as required by the pumpjack unit due to the downhole pumping conditions. A novel control circuitry is connected between the motor starter and the motor stators. The control measures the power drawn by the stators and selects the most optimum configuration thereof for the load required by the pumpjack. This selection operates the motor in the lowest possible torque mode, which is considered the best electrical and mechanical operation of the pumpjack apparatus.

Abstract: The alternating current motor stator of a polyphase motor has each coil wound of at least two separate conductors. The terminal ends of each conductor is encoded for separate circuit interconnection to other conductors of other coils of the motor stator. The coils are inserted into the stator with a single coil side per slot and appears as a conventional chain winding. The bi-filar wound coils have the encoded ends connected to obtain the benefits of double delta winding connections. The coils are paired and selectively connected to each other by speed responsive switches to define a double delta run winding with the phase windings connected in parallel and a double-delta start winding.

Abstract: A controlling system for a pole change electric motor of the type wherein the polarity of electric currents flowing through some of stator windings is changed to change the number of poles thereby to vary the rotational frequency of the motor. The system comprises a reactor which is connected, during running of the motor at a high speed, in series to a power circuit for supplying power to the motor, whereby the motor is driven by way of the reactor when the motor is changed over from a low to a high speed running.