Abstract: A fan assembly includes a shroud attached to a motor housing to prevent negative pressure from developing within the motor housing and prevent moisture from being drawn into drain openings. The assembly includes a fan, a motor, a motor housing, and a fan control. The motor and fan control are disposed within the motor housing. The motor housing includes drain openings to permit the motor housing to be assembled and to permit moisture to drain to the environment from the motor housing. The shroud is attached downstream from the fan such that the drain openings remain open to the environment.

Abstract: A motor drive system includes an electric motor including a rotor shaft, a first main winding and a second main winding. The first and second main windings are selectively energizable to operate the motor at first and second speeds, and at least one of the windings is a permanent split capacitor winding. A transmission is coupled to the rotor shaft, and the rotor shaft engages the transmission without employing a clutch mechanism.

Abstract: A circuit is provided for use in a synchronous generator excitation system. The circuit comprises a three-phase bridge having six legs. The bridge is connected with an AC power supply. A thyristor is provided in each of the six legs, wherein the thyristors provide a path for a device current. A free wheeling diode functions as a de-excitation means connected in parallel with the three-phase bridge. The free wheeling diode provides a discharge path for a field current.

Abstract: An electric power line communication system operates with an electric power distribution system to provide through premises power distribution lines highly reliable communication links among receiving devices electrically coupled or located in proximity to the premises power distribution lines. A power line transceiver is designed to transmit and receive through the premises power distribution lines modulated carrier signals conveying information over the communication links. The power line transceiver operates in a transmitter mode as an intentional radiator to emit modulated carrier signals by transmitting them at a frequency band and a power level sufficient to form by electrical conduction a communication link with a modulated carrier signal receiving device.

Abstract: A differential protective relay and method for a microprocessor-based bus differential protective relay that ensures fast and sensitive operation under internal fault conditions and offers improved stability during external fault and other non-internal fault conditions. The method uses a two-slope differential characteristic to cope with small CT transformation errors without reducing relay sensitivity. The method can also use a saturation detector to switch dynamically between the 1-out-of-2 and 2-out-of-2 operating mode depending whether or not the CTs saturate. In a 2-out-of-2 operating mode, both the differential and directional elements must confirm a fault for the relay to trip. In a 1-out-of-2 mode, if saturation is not detected, the relay can trip without checking the fault direction.

Abstract: A fan assembly includes a vibration damping system to reduce induced vibrational energy generated as a result of fan motor operation. The vibration damping system includes a plurality of arms and damping material. The vibration damping system arms extend between a fan motor housing and a shroud assembly disposed circumferentially outward from the fan motor housing. The damping material is attached to an end of each of the vibration damping system arms and connects each arm to the shroud assembly. The damping material absorbs induced vibrational energy generated by fan motor operation.

Abstract: An active snubber circuit having a controllable dV/dt. The circuit includes a power device and surface mount components including a resistor having a value selectable to control the dV/dt. The use of surface mount components achieves a low profile, small size circuit that can advantageously be used to eliminate noise generated by contact arcing, to dissipate arc energy while clamping to a predetermined voltage value, and in power conversion applications to provide a desirable dV/dt, among other applications.

Abstract: Systems, methods and apparatus for winding conductive wires for a stator of an electric motor. In one embodiment, a hysteretic tensioning apparatus is utilizing to substantially stabilize tension in a conductive wire supplied to a winding machine. The hysteretic tensioning apparatus includes a support member, a brake member, and four idler arms. The brake member is rotatably mounted to the brake member and configured to engage the conductive wire. The idler arms each are spring mounted to the support member and also are configured to engage the conductive wire. The conductive wire is extended across the support member so that it extends between adjacent idler arms and the brake and is inserted into the winding machine.

Abstract: The flux producing current limit of the motor control is adjusted to control the vibration of a motor. The flux producing current may be profiled in relation to the speed of the motor to compensate for excessive motor vibration.

Abstract: A circuit breaker rotary contact arm is used within a plurality of single pole modules ganged together to form a single multi-pole circuit breaker. To provide for use in quiescent conditions having high ampere ratings, low ampere rated rotary contact arm assemblies are combined in parallel to form a higher rated single pole module, which are then ganged together to form a single multi-pole circuit breaker having a high quiescent ampere rating.

Abstract: Methods and control systems for improving performance in an air filtration system are disclosed. The method includes monitoring performance of a blower motor in the air filtration system and adjusting blower motor torque based upon a measured airflow or a measured static air pressure within the air filtration system.

Abstract: A power supply booster module for a programmable logic controller system replaces the primary power supply for a number of modules within the system. The power supply booster module allows high power consuming or highly complex modules to be used within a programmable logic controller system. The power supply booster module eliminates the problems present in prior programmable logic controller systems where the primary power supply could not output enough current to adequately power all of the system modules or modules that have a high power requirement.

Abstract: Grouped gating control logic allows for one or more inputs in a group to be active at any given time. Once an input signal in a group is active, all other pulse trains received in the same group can be locked out. Thus, by using a finite state machine to control gate pulses, the noise margin of the gating unit can be regulated and an extra level of protection is available should one of the input gating signals be defective.

Abstract: A rotor mount assembly, located between a rotor shaft and a plurality of magnetic elements, resiliently damps vibrations induced from the plurality of magnetic elements. The rotor mount assembly includes a first resilient ring, a second resilient ring, and a laminated spacer. The laminated spacer includes laminates from a stator core center punch. Both resilient rings include an inner metal insert which, in one embodiment, comprises laminates.

Abstract: A refrigeration control system containing a chamber in a fresh food compartment of a refrigerator. In one embodiment, a fan motor is positioned between an evaporator and the chamber. The fan motor speed or torque is adjusted to control the volume of cold evaporator air blown into the chamber. The rate of air flow to the chamber adjusts the temperature of the chamber.

Abstract: A system and method for synchronizing power system data gathered in response to unscheduled power system events such as faults. A plurality of protective devices communicate over a peer-to-peer communication network, and when a first device detects the occurrence of a power system event, the device records cycles of power system data before, after, or surrounding the power system event. The first device informs remote devices via the network of the event and a time tag associated with the event, and the remote devices record synchronized power system data.

Abstract: A computer-implemented method for evaluating tool performance is described which includes maintaining tool history data in an electronic memory, updating the tool history data with tool servicing data, determining from the tool history and servicing data a predicted tool remaining useful life, and displaying the predicted useful life on a computer output device. Average tool data is compared to tool benchmark data to determine tool efficiency. Tool servicing, performance and efficiency data are maintained in a spreadsheet format. Data entered into one spreadsheet is used to update a plurality of spreadsheets. The spreadsheet format allows manufacturers to keep abreast of tool performance over time and in a plurality of locations and to anticipate tool rebuild and replacement requirements.

Abstract: A bearing system includes a housing with first and second relief cuts, and a bearing assembly that includes an inner race and an outer race. An adjust screw contacts a preload spring positioned adjacent the outer race. The preload spring exerts a force on the outer race. The outer race includes a first and second edge, and a connecting portion. The first and second edges are positioned adjacent the first and second relief cuts respectively. The connecting portion contacts a bearing bore surface while the first and second edges of the outer race do not contact the bore surface.

Abstract: A method of adjusting speed and torque of a dynamoelectric machine is disclosed. The machine includes a main winding, and a divided winding each configured to generate a plurality of poles. The method includes the steps of energizing the main winding and controlling the amount of electromagnetic flux at each pole.

Abstract: A bearing load washer that permits assembly of electric motors with the rotor shaft in a vertical position and extending downward is described. The bearing load washer includes a plurality of portions that form a non-planar, wave shaped, substantially circular shaped, washer body. The washer includes a center opening that is sized so that an electric motor rotor shaft can extend through the washer body. The washer includes an outer circumferential surface and at least one raised area extending radially from the outer circumferential surface. The raised areas are configured to increase the outside diameter of the washer so that the outer circumferential surface engages the inner surface of an endshield bearing pocket at each raised area of the outer circumferential surface.