Abstract: An electric motor assembly is disclosed. The electric motor assembly can include a plurality of electric motors coupled to a common gear assembly. Individual motors within the electric motor assembly can be dynamically controlled to increase motor efficiency at a given torque and RPM output.

Abstract: An electric motor assembly is disclosed. The electric motor assembly can include a plurality of electric motors coupled to a common gear assembly. Individual motors within the electric motor assembly can be dynamically controlled to increase motor efficiency at a given torque and RPM output.

Abstract: An environmental control unit for use with a transport container is disclosed. The environmental control unit includes a thermoelectric device, a fan configured to blow air across the thermoelectric device, a cooling module, a controller in electronic communication with the thermoelectric device and the fan, and a communication module in electronic communication with the controller. The communication module is configured to transmit parameters of the environmental control unit to a computing device through wireless communication. The controller is also configured to determine a present location of the transport container, determine a destination of the transport container, evaluate an internal temperature of the transport container, and control an on or off condition of the thermoelectric device based on the present location, the destination, and the internal temperature of the transport container.

Abstract: A multi-port storage system includes a dynamo-electric machine with integral rotor inertia forming a primary energy storage system. The dynamo-electric machine has a primary stator winding configured to accept multiple AC input power sources, and has at least two secondary stator windings configured to deliver electric power to multiple loads at different power, frequency and voltage levels. A secondary energy storage system is coupled to the primary energy storage system, and is configured to convert its stored energy to electric power. The dynamo-electric machine is configured to enhance and buffer the secondary energy storage system, and is configured to improve the conversion of the stored energy to electric power. The system may include a step-up transformer responsively coupled to one of the secondary stator windings.

Abstract: Embodiments of the invention may transfer energy from a flywheel motor-generator to a capacitor bank in response to detecting an input to increase the speed of a vehicle, and transfer energy from a drive wheel motor-generator to a capacitor bank in response to detecting an input to decrease the speed of the vehicle. The flywheel motor-generator may function to transfer energy to and from a flywheel included in a gyroscope-stabilizer of the vehicle, while the capacitor bank, which includes a battery, may function to transfer energy to and from a drive wheel of the vehicle.

Abstract: A motor for a plate of a labelling machine comprises a housing with a connecting portion for connecting the motor to a carousel of the labelling machine, a motor shaft pivotally supported within the housing, a coupling flange having a first end connected to the motor shaft and a second end that can be connected to the plate. The motor shaft and coupling flange are joined as one piece such as to form a one-body shaft-flange unit.

Abstract: A motor drive apparatus includes an AC/DC converter which converts AC power supplied from a power supply to DC power, a DC/AC converter which converts DC power to AC power and vice versa, a DC link unit which connects the DC side of the AC/DC converter to the DC side of the DC/AC converter and delivers the DC power from one to the other and vice versa, an energy storage unit which includes at least one capacitor storage unit and at least one flywheel storage unit each of which is connected to the DC link unit and stores or supplies the DC power, and an energy control unit which performs control so that the energy storage unit stores or supplies the DC power.

Abstract: A drive signal for a motor-driven mechanical system has zero (or near zero) energy at an expected resonant frequency of the mechanical system. These techniques not only generate a drive signal with substantially no energy at the expected resonant frequency, they provide a zero-energy “notch” of sufficient width to tolerate systems in which the actual resonant frequency differs from the expected resonant frequencies.

Abstract: A mechanical energy accumulator, suitable for being mounted in a vehicle has a spherical housing with three pairs of flywheel assemblies mounted therein. Each of the pair of flywheel assemblies is rotatable in opposite directions about a respective axis. Each of the axes are perpendicular to one another. At least one permanent magnet motor is mounted within the flywheel assemblies. Each of the flywheels of the flywheel assemblies has a double conical flywheel base, a motor-generator suitable for driving the double conical flywheel base, and a flywheel lid covering the motor-generator. The mechanical energy accumulator may be mounted in a shell having an expansion member. The mechanical energy accumulator has a strong side and a weak side due to varying retention strength of windings therearound so as to create a controlled burst.

Abstract: A motor control of a motor has a DC circuit with a back-up capacitor and a switching device that can connect a motor to the back-up capacitor. A spring device applies a restoring force to the rotor of the motor when deflected from an idle position. When the DC Circuit feeds energy into the back-up capacitor from a power supply network, a control device activates switching elements of the switching device to adjust an actual deflection of the rotor to a required deflection. When the rotor is deflected from the idle position and the back-up capacitor receives no energy from the power supply network, the control device, supplied with energy by the back-up capacitor, sets the required deflection to the idle position and activates the switching elements such that the motor, upon being restored by the spring device, feeds energy into the back-up capacitor via the switching elements.

Abstract: A lifting hook device includes a fixed hook for lifting disposed at a head section of a hollow body having an inside maintained airtight, and a rotatable hook for suspending a load, the rotatable hook has a shaft section rotatably supported in the body and vertically suspended from a bottom section, a motor for rotating the shaft section of the rotatable book about the axis of the shaft section through a rotating mechanism, an azimuth sensor mounted to the rotatable hook and detecting the rotational azimuth of the rotatable hook, and a control section for controlling rotation of the motor to restrict the orientation of the rotatable hook to a predetermined direction.

Abstract: A method of initiating sequential pulse firing of a motor to reduce energy consumption in machines that have both rotational and linear kinetic energy stored in them by pulsing the motor at variable frequency without reducing total kinetic energy in the machine below a predetermined level.

Abstract: An energy storage device having a variable momentum of inertia uses centrifugal forces acting on movable masses to self adjust its moment of inertia. The adjustment of the moment of inertia occurs without any additional energy input. Energy is stored as rotational kinetic energy and potential elastic and/or gravitational energy.

Abstract: The present invention provides a flywheel apparatus for use as an energy storage system, the apparatus comprising: a housing unit having a base; a flywheel assembly mounted within the housing unit, the assembly comprising a flywheel supported by a rotatable axle arranged to enable rotation of the assembly within the housing, the axle defining an axis of rotation; stabilising means located within the housing unit arranged to stabilise rotation of the flywheel assembly about the rotation axis; and levitation means arranged to levitate the flywheel assembly above the base of the housing unit, in order to create a clearance between the flywheel assembly and the base of the housing unit.

Abstract: A device includes a rotor and a stator with coils arranged to form a phase element. The phase element includes a first coil group including a first coil and a second coil and a second coil group including a third coil and a fourth coil, where the rotor is positioned between the first coil group and the second coil group. The device also includes one or more switches that enable reconfiguration of the phase element by switching an electrical configuration of the coils. In a first mode, the coils are arranged with the first coil in a first coil path and the second coil in a second coil path that is coupled in parallel with the first coil path. The coils are arranged such that a voltage generated across the first coil path is substantially equal to a voltage generated across the second coil path.

Abstract: Embodiments of the present invention provide a drive signal for a motor-driven mechanical system whose frequency distribution has zero (or near zero) energy at the expected resonant frequency of the mechanical system. The drive signal may be provided as a pair of steps sufficient to activate movement of the mechanical system and then park the mechanical system at a destination position. The steps are spaced in time so as to have substantially zero energy at an expected resonant frequency fR of the mechanical system. The drive signal may be filtered to broaden a zero-energy notch at the expected resonant frequency fR.

Abstract: An arrangement for supplying power to a system includes a first electric drive unit constructed to supply mechanical power to or receive mechanical power from a first coupled system of machines and a second electric drive unit constructed to supply mechanical power to or receive mechanical power from a second coupled system of machines. The first and second coupled system of machines are constructed to receive mechanical power or mechanical energy or to supply mechanical power or mechanical energy. The arrangement further includes a first kinetic energy storage device having a first electrical energy exchange machine which is electrically connected to the first electric drive unit, and a second kinetic energy storage device having a second electrical energy exchange machine which is electrically connected to the second electric drive unit. The first kinetic energy storage device is coupled to the second kinetic energy storage device.

Abstract: A drive signal for a motor-driven mechanical system has zero (or near zero) energy at an expected resonant frequency of the mechanical system. The drive signal may be provided in a series of steps according to a selected row of Pascal's triangle, wherein the number of steps equals the number of entries from the selected row of Pascal's triangle, each step has a step size corresponding to a respective entry of the selected row of Pascal's triangle, and the steps are spaced from each other according to a time constant determined by an expected resonant frequency of the mechanical system.

Abstract: An electric drive system comprising an electric machine comprising a rotor and a stator, a power converter electrically coupled to the electric machine and configured to convert a DC link voltage to an AC output voltage to drive the electric machine, and a single cooling loop, wherein the electric machine and the power converter are integrated within the single cooling loop.

Abstract: A machine has a basic body and a machine element. The machine element can be moved relative to the basic body by an electric working drive which is connected to an electric supply system via a working converter. An electric buffer drive is connected to the electric supply system via a buffer converter. The working converter and the buffer converter are controlled by a control device in line with a predetermined travel movement of the machine element in a coordinated manner. The coordination is such that a total load on the supply system by both converters together during the total travel movement of the machine element remains below a maximum load prompted by the working converter alone. The buffer drive has a drive shaft which has no flywheel connected to it.

Abstract: A flywheel is described having a rotor constructed of wire wound onto a central form. The wire is prestressed, thus mitigating stresses that occur during operation. In another aspect, the flywheel incorporates a low-loss motor using electrically non-conducting permanent magnets.

Abstract: A drive apparatus with at least one synchronous motor, a converter and a mechanical energy buffer able to be fed from an energy supply network, which, for converting mechanical energy into electrical current, includes a first asynchronous machine, and a method of operation for such a drive apparatus are specified, with which or in which the energy buffer, especially its first asynchronous machine is directly electrically connected via a switchover device to the at least one synchronous motor, so that the converter included in the drive apparatus is bypassed for such a switch position of the switchover device and the converter accordingly does not have to be designed for currents which flow in such a switch position of the switchover device.

Abstract: An arrangement for supplying power to a system includes a first electric drive unit constructed to supply mechanical power to or receive mechanical power from a first coupled system of machines and a second electric drive unit constructed to supply mechanical power to or receive mechanical power from a second coupled system of machines. The first and second coupled system of machines are constructed to receive mechanical power or mechanical energy or to supply mechanical power or mechanical energy. The arrangement further includes a first kinetic energy storage device having a first electrical energy exchange machine which is electrically connected to the first electric drive unit, and a second kinetic energy storage device having a second electrical energy exchange machine which is electrically connected to the second electric drive unit. The first kinetic energy storage device is coupled to the second kinetic energy storage device.

Abstract: The Portable Multi-stack Flywheel Energy Storage Assembly stores energy from any electrical grid or other energy source such as wind turbines and photovoltaic solar power to a flywheel assembly. The invention is comprised of a motor/generator with a combination of multi-stacked flywheels, positive locking roller stops and speed activated clutches. The preferred embodiment would utilize variable inertia flywheels that has a liquid chamber which can be filled after assembly allowing greater portability than conventional flywheels. The rotating liquid provides the mass that spins up with less initial energy, requires lower operating speed for greater safety and reduced cost, and can be drained to move to another location if desired. When the power source is removed from the motor, the spinning flywheels cause the motor/generator to function in its generator mode, thereby supplying needed electrical energy back into the system.

Abstract: Techniques for flywheel energy storage devices including magnetic bearings and/or magnetic drives are generally disclosed. Some example magnetic bearings may include a flywheel magnet and a support magnet arranged to magnetically suspend a rotating flywheel. Some example magnetic drives may include at least one drive magnet arranged to magnetically engage a diamagnetic material associated with the flywheel to exert torque on the flywheel.

Abstract: A system for managing energy consumption in a heave-compensating drawworks includes a power supply, a winch drum connected to the power supply so as to receive power from the power supply, a flywheel connected to the winch drum and to the power supply, and a controller connected to the power supply and to the winch drum for passing energy to and from the flywheel during an operation of the winch drum. The flywheel includes a disk rotatably coupled to an AC motor. The power supply includes a first pair of AC motors operatively connected on one side of the winch drum and a second pair of AC motors operatively connected on an opposite side of the winch drum.

Abstract: The dual drive electric regenerator (DDER), an electric power regenerative device in which a heavy driven-backend flywheel combination being coupled directly to the drive shafts of a specially designed electric generator with dual drives. The driven flywheel with magnetic Pole pieces attached to its circumference area being rotated by the magnetic forces imparted from a driver flywheel with magnetic Pole pieces attached to its circumference surface and rotated by an electric driver motor with its speed being controlled electronically. The DDER expends less input power than the output power generated by the flywheel combination and converted to electrical power by the said generator. The initial power to start the motor being derived from an internal battery. A part of the output power generated being used as the input power through recharging the battery continually and the rotational process being sustained by completing a power regenerative cycle.

Abstract: This disclosure relates to transient energy systems for supplying power to a load substantially instantaneously on demand. Transient energy systems may include a flywheel coupled the rotor of an induction motor generator. One embodiment of the disclosure refers to systems and methods for reducing loads on a bearing in a transient energy system. In another embodiment, the disclosure refers to an induction motor generator that is optimized for high power transient power generation, yet low power motor operation. Yet another embodiment of the disclosure refers to using a flywheel as a drag pump to cool components of a transient energy system. In yet another embodiment, a slip control scheme is discussed for regulating a DC bus. In yet a further embodiment of the disclosure a method is provided for reducing unnecessary turbine starts by making turbine start a function of the rotational velocity of a flywheel.

Abstract: An energy storage device including at least one shaft member, at least a pair of flywheels including a first flywheel and a second flywheel larger than the first flywheel, each flywheel associated with the at least one shaft member, a clutch assembly associated with each of the flywheels, at least one low power input device, and a power take off means associated with the second flywheel, wherein the first flywheel is rotated using a low power input device and is accelerated to a predetermined rotational velocity whereupon the clutch assembly engages to connect the first and second flywheels allowing inertial and kinetic energy to transfer between the flywheels to accelerate the second flywheel.

Abstract: A power source for a vehicle includes at least one toroidal ring positioned in a housing. The toroidal ring includes magnetic material such as permanent magnets. The toroidal ring is magnetically levitated in the housing. A propulsion winding is coupled with the housing and energizable via a power signal to move the toroidal ring. Once moving, the magnetic material and the propulsion winding cooperate to produce electrical power and/or provide a stabilizing effect for the vehicle. In some applications, such as in an aircraft application, two or more toroidal rings may be used and rotated at counter directions so as to produce a predetermined net angular momentum.

Abstract: A method for controlling a driving tool having a power source, a driver, an actuator, a follower, and a control unit. The power source includes a motor and a flywheel that is driven by the motor. The actuator is configured to selectively move the follower to push the driver into frictional engagement with a surface of the flywheel. The control unit is configured to selectively activate the electric motor and the actuator. The control unit includes a speed sensor that is configured to sense a rotational speed of an element of the power source and produce a speed signal in response thereto. The method includes: directly determining a rotational speed of an element in the power source; controlling electrical power provided to the motor based on the rotational speed of the element in the power source to cause the flywheel to rotate at a predetermined speed; and actuating the actuator when a set of actuating criteria has been met, the set of actuating criteria not including a rotational speed of the element.

Abstract: A system for managing energy consumption in a heave-compensating drawworks includes a power supply, a winch drum connected to the power supply so as to receive power from the power supply, a flywheel connected to the winch drum and to the power supply, and a controller connected to the power supply and to the winch drum for passing energy to and from the flywheel during an operation of the winch drum. The flywheel includes a disk rotatably coupled to an AC motor. The power supply includes a first pair of AC motors operatively connected on one side of the winch drum and a second pair of AC motors operatively connected on an opposite side of the winch drum.

Abstract: A drive apparatus with at least one synchronous motor, a converter and a mechanical energy buffer able to be fed from an energy supply network, which, for converting mechanical energy into electrical current, includes a first asynchronous machine, and a method of operation for such a drive apparatus are specified, with which or in which the energy buffer, especially its first asynchronous machine is directly electrically connected via a switchover device to the at least one synchronous motor, so that the converter included in the drive apparatus is bypassed for such a switch position of the switchover device and the converter accordingly does not have to be designed for currents which flow in such a switch position of the switchover device.

Abstract: A mobile electronic apparatus includes a storage device for storing electrical energy and a rotating mechanism configured to energize the apparatus. The rotating mechanism includes a motor, a shaft connected to the motor, and a mass eccentrically attached to the shaft, where the motor is configured to rotate the shaft and the mass to cause the mobile electronic apparatus to vibrate when activated, where motion of the mobile electronic apparatus is configured to cause the mass and the shaft to rotate with respect to the motor, and where rotation of the shaft with respect to the motor is converted into electrical energy. The apparatus also includes circuitry for harvesting the electrical energy and for recharging the storage device with the harvested electrical energy.

Abstract: This disclosure relates to transient energy systems for supplying power to a load substantially instantaneously on demand. Transient energy systems may include a flywheel coupled the rotor of an induction motor generator. One embodiment of the disclosure refers to systems and methods for reducing loads on a bearing in a transient energy system. In another embodiment, the disclosure refers to an induction motor generator that is optimized for high power transient power generation, yet low power motor operation. Yet another embodiment of the disclosure refers to using a flywheel as a drag pump to cool components of a transient energy system. In yet another embodiment, a slip control scheme is discussed for regulating a DC bus. In yet a further embodiment of the disclosure a method is provided for reducing unnecessary turbine starts by making turbine start a function of the rotational velocity of a flywheel.

Abstract: The present invention provides an electro-mechanical energy exchange system with a variable speed synchronous reluctance motor-generator having an all-metal rotor. A bi-directional AC-to-DC electric power converter interconnects the motor-generator with a DC bus. First and second hybrid controllers provide current regulation for the motor-generator and voltage regulation for the DC bus. Use of both feedback and feedforward control elements provides a controller particularly suited for operating high speed devices.

Abstract: A motor is provided that includes multiple sets of independent stator windings that are not magnetically coupled, which allows the motor to be driven by multiple independent current drivers, and thereby increases the overall torque generated by the motor. In one embodiment, the motor is a brushless DC motor that includes a rotor and a stator. The rotor is configured for rotation, and the stator surrounds at least a portion of the rotor and has multiple sets of independent stator windings wound thereon. Each set of independent stator windings is configured to be independently energized and, when energized, magnetically independent of the other sets of independent stator windings.

Abstract: A system comprising at least one flywheel, a first motor, a dynamo, and a second motor. The first motor may consuming electrical power and urging rotation of the flywheel. The dynamo may use rotational energy received from the flywheel to generate electrical power. The second motor may consuming at least a portion of the electrical power generated by the dynamo. Also, the second motor may have a rating corresponding to a maximum consumption of electrical power that is more than double the maximum consumption of electrical power of the first motor.

Abstract: A motor is provided that includes multiple sets of independent stator windings that are not magnetically coupled, which allows the motor to be driven by multiple independent current drivers, and thereby increases the overall torque generated by the motor. In one embodiment, the motor is a brushless DC motor that includes a rotor and a stator. The rotor is configured for rotation, and the stator surrounds at least a portion of the rotor and has multiple sets of independent stator windings wound thereon. Each set of independent stator windings is configured to be independently energized and, when energized, magnetically independent of the other sets of independent stator windings.

Abstract: Certain exemplary embodiments can comprise a method comprising: receiving electrical energy from a braking system of a vehicle at a working coil, the vehicle comprising a first wheel drive comprising a first electric motor; and via the working coil, transferring the electrical energy to a mass related to the vehicle via Hall Effect, the transferred electrical energy converted to heat energy in the mass.

Abstract: Certain exemplary embodiments can comprise a method comprising: receiving electrical energy from a braking system of a vehicle at a working coil, the vehicle comprising a first wheel drive comprising a first electric motor; and via the working coil, transferring the electrical energy to a mass related to the vehicle via Hall Effect, the transferred electrical energy converted to heat energy in the mass.

Abstract: A flywheel energy storage system for preventing power interruptions to a load from interruptions of primary power includes a flywheel supported for rotation about an axis on a bearing system, and a motor-generator having a rotor coupled with the flywheel, and having a stator with multiple armature windings and a field coil. The field coil generates flux that passes through the armature windings as the rotor rotates to produce torque for accelerating the flywheel during charging, and produces electrical power from the flywheel during discharge. The armature windings are energized by a DC buss that is supplied by a rectifier connected to primary power. The flywheel system provides instantaneous full power capability along with output control for extracting more energy from the flywheel. The field coil is oversized and is powered in standby operation to produce an armature back emf that is at least 75% of the DC buss voltage.

Abstract: A flywheel energy storage system (10) includes a vacuum enclosure (18) having a flywheel (12), motor/generator (14), and a shaft (16) enclosed within. The flywheel and motor/generator combination are designed to minimize bearing loads and thus increase system life, reliability and safety.

Abstract: A flywheel energy storage device, for producing electrical power in an allowable range of operating voltages for an output load, includes an energy storage flywheel supported for rotation on a bearing system, and a brushless motor and a brushless permanent magnet generator for accelerating and decelerating the flywheel for storing and retrieving energy. The generator has a multiplicity of windings for producing output power from the generator by a magnetic coupling that provides output power DC voltage. An out regulator circuit provides variable DC voltage that is maintained within the allowable range for connected loads as the flywheel slows during discharging. The output regulator circuit includes electronic switches for switching connections of the windings to change the number of windings connected to the output to maintain output power DC voltage within the allowable range. The switching occurs less than once per every 10 revolutions of the flywheel.

Abstract: A device for preventing power interruptions to a DC bus includes a flywheel supported on bearings for rotation inside a chamber having a drag reducing atmosphere within a container. During charging, the flywheel is driven by an integral brushless permanent magnet excited motor/generator for storing energy, and during retrieval of the stored energy, the flywheel drives and is decelerated by the same motor generator. A closed loop operated synchronous inverter delivers synchronous electrical power to the armature coils of the motor/generator for accelerating the motor/generator. A rectifier connects the armature coils of the motor/generator to the DC bus. Upon an interruption of primary utility power, the motor/generator supplies unregulated voltage power to the DC bus through the rectifier, and the voltage of the unregulated voltage power to the DC bus falls as the flywheel slows during discharge of useable energy from the flywheel through the motor/generator to the DC bus.

Abstract: The invention, intended primarily for use in a steel flywheel power source (30), provides a vacuum system and a method of maintaining a vacuum inside a flywheel chamber (32) for the life of the power source (30). The vacuum system combines the use of cleaning and de-gassing treatments in the chamber (32) and vacuum tempering of the steel flywheel (31) with the use of a chemical type metal alloy nonevaporable getter, such as zirconium-vanadium-iron, that cooperatively matches the outgassing of the flywheel (31) and chamber (32) by sorbing those gases that are released. The getter may be reactivated throughout the life of the flywheel system by reheating it with an integral heater that is triggered by a timer instead of a vacuum gauge to increase the system reliability, using power taken directly from the energy stored in the flywheel.

Abstract: Accordingly, the invention provides a speed control for a flywheel energy storage system that provides accurate and reliable speed control for long-term operation. The speed control uses a current limiting means that safely limits the acceleration current to the motor for accelerating flywheel, and a rate controller that digitally switches the acceleration current on and off to maintain the desired steady state speed. The rate controller turns the acceleration current off when the flywheel speed is above the desired steady state speed and then turns the acceleration current back on when the flywheel speed falls below the desired steady state speeds. The digital type speed control can be made both more accurate and reliable by using straightforward on/off control about the desired steady state operating speed.

Abstract: A flywheel uninterruptible power source has a charging system that uses a high frequency pulse width modulated inverter inside the motor drive with a very low frequency, line commutated converter that regulates by switching the alternating current from the utility power at frequencies under 200 Hz and 60 Hz. The placement of the motor power regulation switching is moved from the motor drive preferably to the input AC line current that provides power to charge the flywheel system. The switching is preferably done using natural commutation so that the devices are turned off when the current passes through zero for very low loss and device stresses. Preferable devices for switching include thyristors or triacs. The turn on switching can be accomplished using phase angle firing or in one embodiment zero cross over switching is employed to reduce harmonic distortion and radio frequency interference to the primary source.

Abstract: An data interface module is provided for allowing a user to remotely modify a predetermined number of operating parameters of a motor driven by a motor control and for displaying the same. The interface module includes a micro-controller interconnected to a communications network and a visual display structure. The visual display structure has a first screen which displays a scrollable list of the operating parameters and a second screen which displays a data value for a user selected one of the operating parameters. A user may modify the user selected operating parameter when the second screen is displayed.

Abstract: A control system for an electric motor having an integral flywheel rotor. The motor includes a stator mounted co-axially with the engine crankshaft and a rotor surrounding the stator. A sensor is positioned near the rotor for sensing its rotational speed. The sensor is coupled to a controller. The controller is operable to deliver an output signal to the stator to start the internal combustion engine. While the engine is starting, the processor steps the starter motor from a low speed to a high speed. Once the engine has started and is rotating at a speed greater than a trigger speed, the processor delivers another output signal such that the motor is commutated at a speed that is less than the speed of the rotor to generate a speed slip. By commutating the motor in this manner, it acts as a generator. The speed slip is regulated when the motor is generating electric power so that the motor produces a constant output voltage.