Abstract:
In one aspect, a grounding device for an electric machine having a rotatable shaft is provided. The grounding device includes a wire core having a first end and a second end, and a plurality of conductive fibers coupled to the wire core and extending therefrom. The wire core is configured to couple to the electric machine with at least a portion of the plurality of conductive fibers contacting the shaft such that an electrostatic charge on the shaft is directed through the grounding device to ground.
Abstract:
An axial flux electric machine has a rotatable shaft, a fixed stator core comprising a ferromagnetic material and defining an axis of rotation, and a rotor assembly comprising a plurality of permanent magnets. The rotor assembly is rotatable about the axis of rotation. An axial air gap is defined between the stator core and the rotor assembly. The rotor assembly is axially displaceable towards and away from the stator core. The rotor assembly has a first position wherein the axial gap is a predetermined width greater than zero, and a second position wherein the axial gap is zero, such that the rotor assembly and the stator core contact each other.
Abstract:
In one embodiment, a permanent magnet rotor for use with a stator is provided. The permanent magnet rotor includes at least one permanent magnet and a substantially cylindrical rotor core including an outer edge, a hub having an inner edge defining a central opening, and a plurality of independent pole pieces spaced from the hub radially about the central opening. The rotor core further includes at least one radial aperture extending radially from the outer edge through the rotor core between adjacent independent pole pieces, the at least one aperture configured to receive the at least one permanent magnet.
Abstract:
A furnace assembly comprising a non-condensing furnace with a draft inducer. The draft inducer includes a permanent magnet electrically commutated motor and a draft inducer blower fan. The motor includes a stator, a rotor, a motor cooling fan, and a controller. The rotor being rotatable relative to the stator, the fan being operatively coupled to the rotor such that rotation of the rotor causes rotation of the fan, the controller being configured to selectively operate the motor in first and second different torque ranges of the rotor, with the first and second torque range operating within a fixed percentage and within a fixed percentage of each other. The controller being configured such during normal operation, the motor is not operable at any torques between the first torque range and the second torque range except during transitionary periods.
Abstract:
A drive circuit is provided for reducing conducted electromagnetic interference provided by a power line to a motor controller. The drive circuit includes an EMI filter having first and second EMI filter input terminals, and first and second EMI filter output terminals. The first input terminal is configured to be coupled to a first AC line output and the second input terminal is configured to be coupled to a second AC line output. The drive circuit includes a rectifier portion having first and rectifier input terminals coupled to the first and second EMI output terminals, respectively. The drive circuit includes at least two series-coupled filter capacitors after the rectifier portion and a PFC choke coupled at a first end to one of the EMI filter output terminals and to one of the first and second rectifier input terminals, and at a second end between the series-coupled filter capacitors.
Abstract:
A motor control system includes an inverter and a plurality of current sensors each positioned in-line between the inverter and a phase coil of the motor. Each current sensor measures the current provided to each phase coil of the motor and provides a signal indicative of each phase current to a controller. In some embodiments, the currents sensors are provided as one or more current sense integrated circuits. A protection circuit protects the current sense integrated circuit from ground bounce by coupling a diode and an opposite facing Zener diode in series between the power supply pin and the ground pin of the integrated circuit.
Abstract:
An electric machine includes a motor having a motor chassis having a first and second end, a stator assembly, and a rotor assembly. The electric machine includes a motor control assembly having a circuit board. The motor control assembly is attached to the stator assembly of the motor. A first end shield is attached to the first end of the motor chassis. The first end shield includes a first opening that is configured to enable a cooling air stream to pass therethrough to cool the motor and the motor control assembly.
Abstract:
A control system for a motor includes an inverter coupled to the motor. The control system further includes a microcontroller coupled to the inverter. The microcontroller includes a processor programmed to measure an input voltage and acquire a back EMF voltage of the motor. The processor is also programmed to control the inverter to regulate the motor voltage based on the input voltage and the back EMF voltage to facilitate controlling the motor.
Abstract:
Protection of a motor controller from a transient voltage and/or an over-voltage condition is described. A drive circuit includes a rectifier portion and at least one inductive device coupled to the rectifier portion. The drive circuit further includes at least one voltage clamping device coupled in parallel with the at least one inductive device, and at least one switching device configured to open as a function of a direct current (DC) link voltage value.
Abstract:
Methods and systems are described for providing power factor correction for high-power loads using two interleaved power factor correction stages. Each power factor correction stage includes a controllable switch that is operated to control the phasing of each power factor correction stage. The phasing of output current from the second power factor correction stage is shifted 180 degree relative to the output current from the first power factor correction stage.