Patents by Inventor Douglas R. Houst

Douglas R. Houst has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4935678
    Abstract: A speed control circuit in combination with an electrical motor for use in a hand-held food mixer operated on AC household electrical current. The motor is a universal type having a series connected armature winding and field winding wherein the field winding includes a plurality of taps each selectably connectable to the current source by a multipoint switch. A Quadrac.TM. semiconductor switch containing a triac and triggering diac in one package conducts electrical current from the current source through the armature winding and the selected portion of said field winding over a portion of each cycle of the current source. A trigger signal causes switching of the semiconductor switch at a predetermined phase angle relative to the voltage waveform of the current source. An error signal of a magnitude proportional to motor speed and based on counter EMF of the motor is generated by the entirety of the field winding.
    Type: Grant
    Filed: November 9, 1989
    Date of Patent: June 19, 1990
    Assignee: Whirlpool Corporation
    Inventor: Douglas R. Houst