Electric motor
First Claim
1. A battery-powered electric motor for generating varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on the battery-powered source comprising:
- a rotor having an axis of rotation;
a stator assembly disposed around said rotor and being inductively coupled to said rotor;
said stator assembly having a plurality of poles;
each of said stator poles having a main winding and at least one fractional-power winding;
said main winding and said associated at least one fractional-power winding on each of said stator poles being wound so that the magnetic flux generated in said associated fractional-power winding will be added to the magnetic flux generated by said main winding to produce an increased magnetic field strength;
power switching means for energizing said main and said fractional-power windings on each of said stator poles;
said power switching means being formed of a plurality of winding drive control circuits each one being associated with one of said main windings and said fractional-power windings for independently energizing said main windings and said fractional-power windings;
said plurality of winding drive control circuits including an input terminal connected to the battery source and output terminals for producing A.C. voltage pulses across said windings;
controller means for controlling selectively said power switching means to vary the rotational speed of said rotor and the amounts of torque supplied to the driven member, andsaid controller means being coupled to each of said plurality of winding drive control circuits for varying the duty cycle of A.C. voltage pulses defining a pulse width modulated waveform; and
each of said plurality of winding drive control circuits being formed of a plurality of transistors connected in a H-bridge network across said battery source, said plurality of transistors being turned on and off for producing said A.C. voltage pulses with alternating polarity and predetermined width.
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Accused Products
Abstract
A fractional-power electric motor is provided to generate varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on a battery-powered source. The electric motor includes a rotor and a stator assembly. The stator assembly is disposed around the rotor and is inductively coupled to the rotor. The stator assembly further includes a plurality of poles, each having a main winding and at least one fractional-power winding. The main winding and associated at least one fractional-power winding on each of the stator poles are wound so that the magnetic fluxes generated therefrom are added. Power switching circuits are provided for independently energizing the main and fractional-power windings on each of the stator poles. A controller is used to control selectively the frequency and duty cycle energization of the power switching circuits to vary the rotational speed of the rotor and the amounts of torque supplied to the driven member.
34 Citations
15 Claims
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1. A battery-powered electric motor for generating varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on the battery-powered source comprising:
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a rotor having an axis of rotation; a stator assembly disposed around said rotor and being inductively coupled to said rotor; said stator assembly having a plurality of poles; each of said stator poles having a main winding and at least one fractional-power winding; said main winding and said associated at least one fractional-power winding on each of said stator poles being wound so that the magnetic flux generated in said associated fractional-power winding will be added to the magnetic flux generated by said main winding to produce an increased magnetic field strength; power switching means for energizing said main and said fractional-power windings on each of said stator poles; said power switching means being formed of a plurality of winding drive control circuits each one being associated with one of said main windings and said fractional-power windings for independently energizing said main windings and said fractional-power windings; said plurality of winding drive control circuits including an input terminal connected to the battery source and output terminals for producing A.C. voltage pulses across said windings; controller means for controlling selectively said power switching means to vary the rotational speed of said rotor and the amounts of torque supplied to the driven member, and said controller means being coupled to each of said plurality of winding drive control circuits for varying the duty cycle of A.C. voltage pulses defining a pulse width modulated waveform; and each of said plurality of winding drive control circuits being formed of a plurality of transistors connected in a H-bridge network across said battery source, said plurality of transistors being turned on and off for producing said A.C. voltage pulses with alternating polarity and predetermined width. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling varying amounts of output torque supplied to a driven member over a wide range of RPM speeds by a battery-powered electric motor so as to reduce power consumption on the battery-power source comprising the steps of:
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providing a plurality of stator poles around a rotor; connecting a main winding and at least one fractional-power winding on each of said stator poles; winding the main winding and the associated at least one fractional-power winding on each of the stator poles so that the magnetic fluxes generated therefrom will be added; switching independently the main and the fractional-power windings on each of the stator poles through a plurality of winding drive control circuits each one being associated with one of the main windings and the fractional-power windings; connecting an input terminal of the plurality of winding drive control circuits to the battery source and generating A.C. voltage pulses across the windings through its output terminals; controlling selectively the energization of the main and the fractional-power windings to vary the rotational speed of the rotor and the amounts of torque supplied to the driven member; varying the duty cycle of the A.C. voltage pulses so as to define a pulse-width modulated waveform; the plurality of winding drive control circuits being formed of a plurality of transistors connected in a H-bridge network across the battery source; and turning on and off a predetermined pair of the transistors to generate the A.C. voltage pulses with alternating polarity and predetermined width. - View Dependent Claims (11, 12, 13, 14)
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15. A battery-powered electric motor for generating varying amounts of output torque supplied to a driven member over a wide range of RPM speeds so as to reduce power consumption on the battery-powered source comprising:
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a rotor having an axis of rotation; a stator assembly disposed around said rotor and being inductively coupled to said rotor; said stator assembly having a plurality of poles; each of said stator poles having a main winding and at least one fractional-power winding, said at least one fractional-power winding having a magnetic field strength between 1/8th and 1/20th of said main winding; said main winding and said associated at least one fractional-power winding on each of said stator poles being wound so that the magnetic flux generated in said associated fractional-power winding will be added to the magnetic flux generated by said main winding to produce an increased magnetic field strength; power switching means for independently energizing said main and said fractional-power windings on each of said stator poles; and means for selectively controlling the energization of said power switching means so that said main and said fractional-power windings on each of said stator poles can vary the rotational speed of said rotor and the amounts of torque supplied to the driven member.
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Specification