Abstract: The output voltage generated by permanent magnet generator (PMG) is regulated by controlling a buck/boost voltage applied to selected sub-coils within the PMG. The PMG includes a number of stator coils that are each divided into a number of sub-coils. A buck/boost voltage source generates a buck/boost voltage, and a controller connected to monitor the output voltage generated by the PMG selectively applies the buck/boost voltage to selected sub-coils based on the monitored output voltage. In this way, the controller is able to regulate the output voltage by selectively controlling the buck/boost voltage applied to the selected sub-coils.

Abstract: An electromechanical power transfer system that transfers power between a prime mover and a direct current (DC) electrical system, comprises: a permanent magnet machine (PMM) that has a permanent magnet (PM) rotor coupled to the prime mover, a stator with a multiphase alternating current (AC) winding coupled to an AC bus and a control coil with a winding that has a configuration to generate a magnetic field with flux that varies the reactance of the stator winding with the application of control coil current; a control coil current sensor for generating a control coil current signal that is representative of the level of electrical current in the control coil; an electrical current sensor for generating a DC bus current signal that is representative of the level of DC current through the DC bus; an electrical potential sensor for generating a DC bus potential signal that is representative of the level of DC potential on the DC bus; a fixed pattern active rectifier and inverter system coupled between the AC bu

Abstract: Disclosed is an SR (switched reluctance) generator with improved generation capability in a low-speed range. The SR generator is configured such that an inductance of a phase winding wound around a stator is increased in a low-speed range and is reduced in a high-speed range. Accordingly, a variation rate of the inductance relative to a phase angle is increased in a low-speed range, resulting in an increased output energy in a low-speed range and an improved generation efficiency. The phase winding of the stator may be configured to have a single phase. Accordingly, since the generator is configured with the reduced number of switches, it can be manufactured inexpensively and simply.

Abstract: A starter-generator system is configured to be operable at multiple variable frequencies. The starter-generator includes a rotor and a stator. The rotor is configured to rotate and has a single main field winding wound thereon. The stator has at least a first stator winding set and second stator winding set independently wound thereon. Upon electrical excitation and rotation of the rotor the starter-generator supplies electrical power from each of the stator winding sets at different frequencies. Also, upon electrically exciting one or both of the stator winding sets with appropriate AC power, the rotor will rotate and generate a starting torque.

Abstract: A permanent magnet starter/generator subsystem configured in a fault tolerant architecture is described herein for small engine applications. The system allows for lighter system weight, improved system reliability, higher performance capability and reduced maintenance.

Abstract: A hand-held power tool has a drive motor driving a tool and a generator. One or more heating devices having one or more heating elements are provided. The generator supplies the one or more heating devices with energy. A control device controls a power supplied to the one or more heating elements as a function of at least one operating parameter of the drive motor.

Abstract: In a control system, a control unit is connected to a generator and is configured to, when a steep change in a load current flowing through at least one specific electrical load is sensed, control the output of the generator based on the sensed steep change in the load current. This allows variations in a voltage of a power supply system to decrease while converging the voltage of the power supply system to a predetermined target voltage.

Abstract: A control system that can accommodate the wide variations in the output of a generator, such as a permanent magnet alternator, while providing an output with relatively uniform phase ripple. The control system includes a zero crossing detector and variable ramp generator for generating control signals to a switching rectifier to generate a regulated DC signal.

Abstract: A permanent magnet generator voltage regulation system controls the output voltage of a permanent magnet generator. The output voltage of the permanent magnet generator is controlled by configuring the electrical connection of the stator coils. A monitoring device monitors the output voltage generated by the PMG, and a controller selectively configures the stator coil configuration based on the monitored output voltage. A switch array having a number of switches is connected to the stator coils, the switches being controlled by the controller to configure the electrical connection of the stator coils. For instance, to maximize output voltage generated by the PMG, the controller causes the switch array to connect the stator coils in series with one another. To reduce the output voltage, the controller causes the switch array to connect at least some of the stator coils in parallel with one another. In this way, the output voltage of the permanent magnet generator can be coarsely controlled.

Abstract: A generator controller for controlling a permanent magnet generator where each phase of the generator is connectable to a DC link via electrically controllable switches, the controller characterised by a data processor adapted to receive a measurement of generator current output and a demand current, and to form a current error between the demanded value and the measured generator current; derive a target voltage as a function of the current error; and form control signals for the electrically controllable switches as a function of the target voltage.

Abstract: A starter-generator system supplies a controllable torque to a gas turbine engine, to thereby assist in starting the gas turbine engine, by independently controlling excitation frequency and/or voltage magnitude. The starter-generator includes a multi-phase exciter stator, a rotationally mounted multi-phase exciter rotor, a multi-phase main stator, a rotationally mounted multi-phase main rotor, and an exciter controller. The rotationally mounted multi-phase exciter rotor has a plurality of exciter rotor windings wound thereon that, upon excitation thereof with a rotating electromagnetic exciter flux generated by the exciter stator, have non-rectified excitation currents induced therein.

Abstract: A high-power permanent-magnet generator in which a stator winding is divided into a first winding part and second winding parts to keep a number of turns less, and capacitors are installed between any different phases to store a current therein to raise a voltage and thereby yielding a high output. The first and second winding parts of independent from one another are both made in a three-phase arrangement of U-phase, V-phase and W-phase. The first and second winding parts are wound in a way staggered one another by one or two slots separating any two adjacent teeth of the successive stator teeth. Further, output lines of three phases are connected across respective capacitors to the remaining other output lines of different phases. The output lines of the first winding part and the second winding part are all installed with respective switches.

Abstract: A permanent magnet starter/generator subsystem configured in a fault tolerant architecture is described herein for small engine applications. The system allows for lighter system weight, improved system reliability, higher performance capability and reduced maintenance.

Abstract: A voltage regulation system maintains the output voltage of a permanent magnet generator at an essentially constant level. The stator coils located within the permanent magnet generator are divided into a number of sub-coils. A buck/boost voltage can be applied to selected sub-coils such that the output voltage generated by the permanent magnet generator is increased or decreased. A number of switches are connected to the sub-coils to allow the sub-coils to be connected in a number of different configurations. Connecting the sub-coils in a particular configuration and applying a buck/boost voltage to selected sub-coils based on the monitored output voltage allows the voltage regulation system to maintain an essentially constant output voltage.

Abstract: The present invention provides an improved control method and apparatus allowing units arranged at different spaced apart locations to be controlled without the need for a high bandwidth link between the units and the controller. This allows a single controller to control a number of remotely located units.

Abstract: Apparatus and methods are provided for controlling a voltage output of an alternator having a regulated voltage control (RVC). The apparatus includes a processor configured to transmit one of at least two control signals and a switch coupled to the processor and configured to select one of the control signals. One of the control signals is an RVC enable signal, and another control signal is a voltage boost signal. The method includes determining whether RVC requires override, selecting an output voltage mode of the alternator, activating a boosted voltage mode of the alternator by disabling RVC when RVC requires override, and activating an RVC mode by enabling RVC when the RVC does not require override or upon an occurrence of a lapse of a pre-determined amount of time.

Abstract: An automotive generator/motor is driven by a battery via an inverter. Resistance 2Ra0 is expressed by 2Ra0=Vmax/?{square root over (3)} Iamax, where Vmax is a maximum voltage applicable across any two terminals from the inverter and Iamax is a maximum current which must be fed from the inverter into each of the terminals when the maximum voltage Vmax is applied for maximizing torque produced by the automotive generator/motor at a power factor of 1 under voltage saturation conditions, and the armature winding is configured such that resistance 2Ra across any two terminals satisfies a relationship expressed by 0.8Ra0?2Ra?3.8Ra0.

Abstract: A motor-generator system with a current control feedback loop for generating electrical energy in stationary, portable, and automotive applications. The generator includes a housing defining an interior space and including a first portion and a second portion; an electric motor assembly positioned within the first portion of the housing, and operationally coupled to a shaft member for selectively rotating the shaft member; an electric generator assembly positioned within the second portion of the housing and operationally coupled to the shaft member for converting mechanical rotation into electrical energy, the electric generator assembly including a current output for supplying electrical current; and a control assembly operationally coupled between the electric generator assembly and the electric motor assembly the control assembly providing a control current to the electric motor assembly for controlling a speed of rotation induced into the shaft member by the electric motor assembly.

Abstract: A permanent magnet starter/generator subsystem configured in a fault tolerant architecture is described herein for small engine applications. The system allows for lighter system weight, improved system reliability, higher performance capability and reduced maintenance.

Abstract: An alternator system includes a permanent magnet alternator, battery and voltage regulator operatively connected to the permanent magnet alternator and battery for regulating the charging of the battery. The voltage regulator includes a rectifying circuit for rectifying the alternating current and a semiconductor switching element operative for turning the regulator on and off based on a predetermined temperature threshold to prevent overheating of any voltage regulator electronic components.

Abstract: A generating set includes an engie driven generator (PGM) having two sets of stator windings (Ga and Gb). A bi-directional AC/DC converter (BCo) has its AC input connected to a junction between the two sets of stator windings (Ga and Gb) and its DC input connected to a number of the generator (PGM) is converted into an intermediate DC link by a convertor (Col) to produce an output for a load Lo. In normal operation of the system, an emf generated in one (Ga) of the sets of stator windings is rectified by the bi-direcitonal converter (BCo) to charge the energy storages (ESI-ESN) whilst the remainder of the generator output is fed through the converter to the load (Lo). In the event of a stepped increase in the load demand, the bi-directional converter (BCo) is operated to feed energy from the storage devices (ESI-ESN) to the stator windings (Ga) of the generator (PGM) to impart a driving torque to the generator rotor to accelerte the rotor to meet the increased load demand.

Abstract: A control system regulates power to a brushless synchronous generator (BSG) (204) having a permanent magnetic generator (PMG)(210), an exciter (208) and a main generator (206) connected to a rotating shaft (212). The generator control unit (GCU) (202) includes a three phase rectifier (214), a PMG voltage regulator (222), a generator control relay (GCR)(220), a GCU power supply (216) with a backup power source (217), a field switch driver (218), a field switch (219), and a free wheeling diode (221). The BSG (204) is connected to the GCU (202) by coupling the PMG (210) of the BSG (204) to the three phase rectifier (214) of the GCU (202) and by coupling the exciter (208) of the BSG (204) to the PMG voltage regulator (222) and the field switch driver (218) of the GCU (202) and the PMG voltage regulator (222) regulates the voltage of the PMG (210).

Abstract: Disclosed is a brushless generator with permanent magnets, which provides high-speed operation, simple maintenance, lightweight, and stable power. The brushless generator with permanent magnets including a main generator with a stator and a rotor; and an auxiliary generator having a stator made of a hollow stator core and a coil wound around the stator core, and a rotor made of a rotor core rotating within the stator core and a coil wound around the rotor core, where wedges and grooves are formed alternatively on the inner portion of the stator core of the auxiliary generator, and permanent magnets are embedded in the body of the grooves and the coil is wound around the body of the grooves. Accordingly, without the use of a brush, a rated load voltage is generated from the permanent magnets of the auxiliary generator, and voltage variations due to load variations are controlled by the windings of the auxiliary generator.

Abstract: An electrical power distribution system includes permanent magnet generator, and an ac regulator. The ac regulator includes an inverter shunt-connected to the permanent magnet generator, and an inverter control for causing the inverter to regulate voltage at output terminals of the generator by providing reactive power (either leading or lagging) that circulates between the inverter and the generator.

Abstract: A permanent magnet fault tolerant generator 32 is driven by a variable speed shaft 34 to create AC power at terminals 36, converted at 40 to DC power before being applied to a load 38. The converter 40 is a bi-directional device which rectifies AC to DC and also acts as an inverter to synthesize AC from the DC. This synthesized AC waveform is imposed on the terminals 36 to maintain a constant magnitude generator output voltage, regardless of the speed of the shaft 34, and thus regardless of the EMF of the generator. This results in reactive currents flowing between the generator 32 and the converter 40, but allows the generator design have a reduced current rating, resulting in improved generator size and weight.

Abstract: The invention relates to an apparatus for regulating the exciter current for a rotary-current generator. It has a voltage source, a rectifier, three phase windings, an evaluation unit, and a voltage regulator. The evaluation unit has three input terminals, and each of these input terminals is connected to one of the phase windings. The evaluation unit is intended for evaluating the phase voltages derived from the three phase windings, in order to detect error functions of the rectifier and/or of the phase windings. If such unauthorized work states are detected, then via the voltage regulator, the exciter current flowing through the exciter winding is reduced.

Abstract: A starter generator for an internal combustion engine including: a rotating electric machine having a magnet rotor mounted to a crankshaft of the internal combustion engine, and a stator with a three-phase first armature coil and a three-phase second armature coil; a first battery and a second battery connected in series or in parallel; a first driver circuit provided between the first armature coil and the first battery, and a second driver circuit provided between the second armature coil and the second battery; and an inverter that converts voltages of the first battery and the second battery into an AC voltage, wherein drive currents are supplied to the first armature coil and the second armature coil from the first battery and the second battery through switch circuits in the first driver and the second driver, when the engine is started, and induced voltages of the first armature coil and the second armature coil are supplied to the batteries through rectifier circuits in the first driver and the second

Abstract: A system and method is provided for overload and fault current protection of a permanent magnet generator. The system comprises a permanent magnet machine, a DC link, an inverter, coupled between the permanent magnet machine and the DC link, and a controller adapted to provide a linear decrease in voltage for the DC link when the permanent magnet machine is in at least one of an overload and fault current condition.

Abstract: An automatic power supply device for a remote control unit is shown. The device has a rotatable multi-layer disc mounted in an open top casing with a tray slidably mounted in it. The remote control unit is mounted on the tray which is movable up and down when a button of the remote control unit is pressed and released. The disc has printed wire provided in the same area of all layers. The area is located in a spaced manner between magnetic plates mounted in the inside surface of the arms of a U-shaped stator member. Current is generated in the printed wire when the disc is rotated. A capacitor is charged by the current to provide the voltage supply to operate the remote control unit.

Abstract: An electrical power system includes an electric power source, for example, an electrical machine, capable of supplying AC power to a load; a power converter connected to the electric power source; a position estimator for receiving a current feedback signal in Park vector format and providing a synchronous reference frame without the need, for example, of a rotor position sensor in the electrical machine; and a controller configured to provide a voltage command for controlling the power converter, the controller receiving the current feedback signal and a current reference in Park vector format and using the synchronous reference frame, the current feedback signal, and the current reference to produce the voltage command.

Abstract: A system and method are disclosed for providing a control signal to control an excitation level of an alternator. The system includes a first calculation element that receives first, second and third indications of first, second and third output voltages of first, second and third phases of the alternator, respectively, and calculates a first feedback signal in dependence upon the received first, second and third indications. The system additionally includes a second calculation element that receives the first indication and calculates a second feedback signal in dependence upon the received first indication. The system further includes an intermediate signal generation element that receives a target input and the first feedback signal, and in response provides an intermediate signal. The system additionally includes a control signal generation element that receives the intermediate signal and the second feedback signal, and in response provides the control signal.

Abstract: An electronic device in which a braking torque can be increased while reduction in power generation is suppressed, and in which a rotor is prevented from stopping or rotating at an excessive speed. Such an electronic device includes a generator which is driven by an mechanical energy source and a rotation controller which controls the rotational period of the generator.

Abstract: Several sets of magnetic sensors are provided in a magneto motor to sense rotary pole variation of the rotor magnet. One set of magnetic sensors lets the stator portion and the rotor portion generate armature reaction of stronger magnetic flux density, and another set of magnetic sensors corresponds to rotary pole variation of the permanent magnet of the rotor portion in advance to let the motor generate weak magnetic control phenomenon so that the stator portion and the rotor portion generate armature reaction of weaker magnetic flux density. The torsion coefficient KT will decrease to increase the rotation speed of the rotor portion. A motor can be designed to have a larger KT. When the motor needs to operate at higher rotation speeds, a magnetic detection selection circuit will output a detection output signal letting the motor generate a lower KT to increase the rotation speed of the magneto motor.

Abstract: An electrical power distribution system includes permanent magnet generator, and an ac regulator. The ac regulator includes an inverter shunt-connected to the permanent magnet generator, and an inverter control for causing the inverter to regulate voltage at output terminals of the generator by providing reactive power (either leading or lagging) that circulates between the inverter and the generator.

Abstract: In a multiple power source system of the present invention that has an inverter connected to a reactance, such as three-phase coils in a motor, a high voltage battery is connected with a low voltage battery via one transistor (Tr2) and one diode (D2) included in the inverter and one phase coil (U-phase coil) of the three-phase motor. The transistor Tr2 is turned on to make the electric current flow from the low voltage battery to the U-phase coil. The transistor Tr2 is subsequently turned off at a preset timing, so that the electric energy accumulated in the reactance, that is, the U-phase coil, flows through the diode D1 into the high voltage battery and thereby charges the high voltage battery. This arrangement enables the charging process from the low voltage battery to the high voltage battery without any complicated circuit structure for the voltage step-up. The three-phase motor may be unipolar driven with transistors connected to one side of the inverter.

Abstract: A system for deriving electrical power from an engine includes a current inducing module that supplies current to a load such as a chargeable power source. The current inducing module preferably includes a magnet and coil arrangement. The magnet is associated with a rotating element of the engine such that the magnet passes by the coil as the engine element rotates. The current that is induced in the coil is handled using current regulating components to control the amount of power supplied to the chargeable power source. The invention provides a way to electrically power components associated with devices that do not have a battery.

Abstract: A gate terminal plate (1) of a GCT thyristor (90), a connecting substrate (70) of a driving device and a cathode electrode plate (10) are interposed between a set of metal rings (7A) and (7C) fastened to each other with a screw (8). The cathode electrode plate (10) is connected to a cathode post electrode (31) of the GCT thyristor (90). The screw (8) is electrically insulated from the metal ring (7A) and the gate terminal plate (1) through an insulator (9). By this structure, the gate terminal plate (1) and the cathode electrode plate (10) are directly connected to a first metallized layer (5) and a second metallized layer (6) which are provided on two main surfaces of the connecting substrate (70) of the driving device, respectively. Thus, resistance and inductance components in a path for a gate current are reduced and an assembly is simplified.

Abstract: An alternator generates output power at two or more independent voltages. The alternator has two independent output windings configured to generate the power needed for each output. Each output voltage is sensed by a regulator that controls switching rectifiers to supply the current needed to satisfy the electric power demand of the loads connected to each output. After both output load demands are satisfied, the regulator switches off the alternator field. When power demand from either load rises, the alternator field is switched on along with the respective switching rectifier to satisfy the power demand. The output voltage grounds and control signals may be electrically isolated from each other.

Abstract: A control system for a variable frequency generator is disclosed of the type having a main stator winding for providing a generator output, excited by a main rotor winding, and a main exciter rotor winding for energizing the main rotor winding, excited by a main exciter field winding, the control system having:

Abstract: A stator generator for an internal combustion engine comprising a magnet rotor provided on an output shaft of the engine and having main poles of permanent magnet and interpoles of material of high permeability alternately provided thereon whereby it is operated as an electric motor when the engine starts so that a drive current flows through armature coils with each of the main poles and one of the interpoles on the advanced side of the corresponding main pole serving as one rotor pole and it is operated as a magneto generator after the engine starts so that a control current flows through the armature coils so as to generate an output for charging a battery with each of the main poles and one of the interpoles on the delayed side of the corresponding main pole serving as one rotor pole.

Abstract: A device such as an electric motor, an electric generator, or a regenerative electric motor includes a rotor arrangement and a stator arrangement. The stator arrangement has a dielectric electromagnet housing and at least one energizable electromagnet assembly including an overall amorphous metal magnetic core. The overall amorphous metal magnetic core is made up of a plurality of individually formed amorphous metal core pieces. The dielectric electromagnet housing has core piece openings formed into the electromagnet housing for holding the individually formed amorphous metal core pieces in positions adjacent to one another so as to form the overall amorphous metal magnetic core. The device further includes a control arrangement that is able to variably control the activation and deactivation of the electromagnet using any combination of a plurality of activation and deactivation parameters in order to control the speed, efficiency, torque, and power of the device.

Abstract: A regulation system for a permanent magnet generator for generating electrical power and for supplying the electrical power to a load comprises a switching circuit connected between the permanent magnet generator and the load, the switching circuit being capable of regulating the electrical power being supplied to the load and a control circuit connected to the switching circuit, the control circuit for determining the amount of electrical power being supplied by the permanent magnet generator and for controlling operation of the switching circuit to regulate the electrical power being supplied to the load.

Abstract: A hand-held work tool has a housing with a carburetor heater and a grip heater. An internal combustion engine is mounted in the housing and has a crankshaft and an ignition system. The ignition system has a pole wheel with permanent magnets fastened sequentially at a periphery of the pole wheel in the circumferential direction. Charge armatures are mounted in the housing and close the magnetic circuit between neighboring permanent magnets. The charge armatures have legs and excitation coils mounted on the legs. Upon rotation of the pole wheel, the permanent magnets generate an electric current in the excitation coils, wherein a first set of excitation coils is combined to a first partial generator and connected to an electric circuit of the carburetor heater and a second set of the excitation coils is combined to a second partial generator and connected to an electric circuit of the grip heater such that the electric current is supplied respectively to the carburetor heater and the grip heater.

Abstract: An improved three-phase bridge inverter DC link converter power circuit for a portable generator, preferably the generator system described in U.S. Pat. No. 5,625,276 to Scott et al. Dual voltage and variable frequency inverter designs and improved converter designs are disclosed. Embodiments of the present invention avoid a capacitor induced center voltage drift problem found in certain prior art inverter designs.

Abstract: Electrical machine cycloconverter devices are provided that produce output signals in which the frequency, amplitude and phase are independent of rotor speed. The cycloconverters produce highly efficient increased output by providing multi-tap armatures that include multiple armature coils arranged such that at least two coils may be connected in series to an electrical load. Such configurations produce output signals that include multiple distinct voltage amplitude steps. In preferred embodiments, either rotating permanent magnets or field coils in conjunction with rotating steel teeth induce a voltage in the armature coils. The level of induced voltage is determined by the switching sequence of one or more armature coils that are switched ON and OFF in series, parallel, or series and parallel by semiconductor switches.

Abstract: A conventional motor controlling circuit is adapted to control an inverter that drives a permanent magnet generator as a motor to spin an engine to a speed sufficient to permit the engine to start. The commutation frequency is adjusted as a function of speed utilizing an automatic commutation frequency adjustment circuit. This circuit has multiple commutation frequency ranges that overcome a large initial bearing drag during low speed operation while still permitting high speed operation. The automatic commutation frequency adjustment circuit preferably generates first and second voltage ramps that overcome the initial bearing drag and accelerate the generator at a rate fast enough for sufficient back EMF to be generated for a closed-loop commutation phase. A speedup circuit operates during the closed-loop commutation phase to achieve the high speeds typically necessary for engine starting. The inventive circuits even permit a turbine type engine to be successfully started.

Abstract: A discharge lamp lighting device driven by an internal combustion engine is disclosed which is capable of lighting a discharge lamp without using a ballast constituted by a leakage transformer. The device includes a generator which is driven by the internal combustion engine and of which output characteristics exhibit drooping characteristics, so that an output voltage of the generator may be applied to a discharge lamp without using any ballast. Output characteristics of the generator are so set that an output voltage of the generator at a non-load state thereof may be higher than a break-down voltage of the discharge lamp, a short-circuit current of the generator may have a level sufficient to restrict a discharge current of the discharge lamp just after starting of discharge thereof to an allowable level or below, and a voltage across the discharge lamp and a discharge current thereof at a steady state thereof each are kept within a rated range.

Abstract: An electric current generation device includes a rotatable rotor including a magnet assembly establishing a magnetic field proximate the rotor. A stator includes at least one set of coils disposed with respect to the rotor so that rotation of the rotor moves the magnetic field with respect to the coils of the coil set to generate electric current flow in the coil set. The coil set includes an impedance component in communication with the electric current flow to limit the rate of increase of electric current flow generated by the coil set as the rotational speed of the rotor increases. The winding direction of at least one coil with respect to the magnetic field may be opposite the winding direction of the other coils with respect to the magnetic field. Two coil sets may be provided wherein the coils of a first coil set are wound so that the output of the first coil set is out of phase with respect of the output of a second coil set.

Abstract: A permanent magnet generator having a winding split into two equal windings with each of the two windings connected to a separate three phase rectifier block of a pulse width modulated inverter The pulse width modulated inverter includes three (3) IGBT channels across the voltage bus with the neutral created between the separate three phase rectifier blocks.

Abstract: A lightweight engine-driven generator set including a stator having at least first and second windings (preferably three-phase) and a rotor having a soft magnetic core and a plurality of high energy product permanent magnets, separated by consequence poles, disposed proximate the stator such that relative motion of the rotor and stator causes magnetic flux from the rotor to interact with and induce current in the stator windings. The first winding includes a predetermined number of turns corresponding to a first predetermined voltage output; and the second winding includes a predetermined number of turns corresponding to a second predetermined voltage output, the respective windings being grouped together as a unit and wound about the core such that the respective winding coils are wound in continuous close thermal contact with each other.