Abstract: A fan comprises a hub, fan blades, and inserts. The hub comprises outwardly extending mounting tabs that lie along a common horizontal plane. The fan blades are hollow, such that each mounting tab is inserted in the hollow interior of a corresponding fan blade. Each insert is positioned in the hollow interior of each fan blade, between each mounting tab of the hub and the interior surface of the corresponding fan blade. Each insert is configured to position and maintain the chord line of each corresponding fan blade at an oblique angle relative to the horizontal plane of the hub. A kit may include several insert sets to choose from to provide adjustable angle of attack. A fan control system includes a dimmer switch and a control module, which allows the dimmer switch to be used to infinitely adjust the speed of a fan motor within a range.

Abstract: A fan comprises a hub, fan blades, and inserts. The hub comprises outwardly extending mounting tabs that lie along a common horizontal plane. The fan blades are hollow, such that each mounting tab is inserted in the hollow interior of a corresponding fan blade. Each insert is positioned in the hollow interior of each fan blade, between each mounting tab of the hub and the interior surface of the corresponding fan blade. Each insert is configured to position and maintain the chord line of each corresponding fan blade at an oblique angle relative to the horizontal plane of the hub. A kit may include several insert sets to choose from to provide adjustable angle of attack. A fan control system includes a dimmer switch and a control module, which allows the dimmer switch to be used to infinitely adjust the speed of a fan motor within a range.

Abstract: A fan comprises a hub, fan blades, and inserts. The hub comprises outwardly extending mounting tabs that lie along a common horizontal plane. The fan blades are hollow, such that each mounting tab is inserted in the hollow interior of a corresponding fan blade. Each insert is positioned in the hollow interior of each fan blade, between each mounting tab of the hub and the interior surface of the corresponding fan blade. Each insert is configured to position and maintain the chord line of each corresponding fan blade at an oblique angle relative to the horizontal plane of the hub. A kit may include several insert sets to choose from to provide adjustable angle of attack. A fan control system includes a dimmer switch and a control module, which allows the dimmer switch to be used to infinitely adjust the speed of a fan motor within a range.

Abstract: An electromechanical energy conversion system comprising a brushless motor and a stored program controller for controlling motor operation in a plurality of modes in accordance with internally generated and/or external commands.

Abstract: A brushless D.C. motor control system wherein a read-only memory is used to control the commutated winding energization via drive switching circuits. Position sensors detect the position of the rotor relative to the motor stator and principle digital signals which are used as address inputs for the read-only memory.

Abstract: A four quadrant control system for a brushless D.C. motor wherein the windings are energized via a drive switching circuit in a bridge configuration and the switching circuit is in turn controlled by a read-only memory. Pulse-width modulation control signals and position signals are supplied to the read-only memory as addresses together with other control signals. The system operates in a regenerative mode when changing direction and automatically makes a smooth transition into a motoring mode when the back EMF of the motor is no longer large enough to satisfy the requirements of the current loop.

Abstract: A closed loop control system for variable reluctance stepper motors which senses a voltage indicative of motion on the driven windings, uses this voltage to confirm that motion has occurred, compares this voltage with one modeled after a waveform indicative of no motion and effects successive changes in the winding drive states at optimum times.