Abstract: A controller drives a fan's motor to proportionally control fan speed based on changes in heat output from electrical components in a local environment. The controller is connected to a temperature sensor and the fan motor. The temperature sensor senses local environment temperature, while exhibiting a lag time. The controller provides closed loop control and implements a system pole which cancels out the temperature sensor lag time during steady state operations. The controller implements an integration of a difference between sensed temperature and a reference temperature to generate the system pole.

Abstract: A controller drives a fan's motor to proportionally control fan speed based on changes in heat output from electrical components in a local environment. The controller is connected to a temperature sensor and the fan motor. The temperature sensor senses local environment temperature, while exhibiting a lag time. The controller provides closed loop control and implements a system pole which cancels out the temperature sensor lag time during steady state operations. The controller implements an integration of a difference between sensed temperature and a reference temperature to generate the system pole.

Abstract: An elongate vibratory conveyor for moving products is reciprocated by driving a motor with a cyclical nonuniform motion by supplying power nonuniformly to the motor. The conveyor is reciprocated in opposite lengthwise directions, without any substantial movement of the conveyor normal to the lengthwise direction. Motor control circuitry variably drives the motor automatically in response to feedback from a sensor which senses a motion related to the conveyor motion. The feedback signal is compared to a selected one of a set of predetermined different motion patterns, and the motor is driven by supplying power nonuniformly thereto in accordance with the selected motion pattern.

Abstract: A low noise, high bandwidth, sensorless vector control for a brushless DC motor includes a phase locked loop control having a digital counter and ROM look-up table which is responsive to a VCO to generate digital signals representing the sine and cosine of the instantaneous phase angle of the VCO. These signals are modulated by a current command and applied to a two-phase to three-phase converter. A flux sensor senses the air gap flux in the three motor coils and converts this signal to quadrature components which are compared with the output of the look-up table to derive a phase error signal that drives the VCO. Another feature of the invention is a timed self-starting network that cause the VCO frequency to ramp upwards then automatically switch to loop control without any abrupt change in the frequency of the VCO.

Abstract: A transformer bobbin assembly having a first bobbin piece dimensioned to accommodate at least one additional bobbin piece within its central cavity. Each bobbin piece having a pair of flanges, one at each end and perpendicular to its central cavity, defining a channel around the outer surface of the bobbin piece to accommodate a single coil winding. The surface distance over the flange of the larger bobbin piece from the end of its cavity to the top of the flange plus the thickness of this flange is selected to provide at least the minimum creepage and clearance distances required by a selected industrial safety standard.If two bobbin pieces, each being fully insertable within the interior cavity of the larger bobbin piece, are utilized, the necessary creepage and clearance distances between the coil wound on each of these nesting bobbin pieces is provided by a web within the cavity of the larger bobbin piece. This web is centrally located within and parallel to the flanges of the larger bobbin piece.