Patents by Inventor Elmer W. Madsen

Elmer W. Madsen 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: 5309076
    Abstract: The present invention provides a drive and control circuit for a single phase, brushless DC motor. The drive and control circuit includes an integrated circuit having a maximum rated voltage lower than the maximum net voltage of the overall circuit. Internal transistors in the integrated circuit are used to drive the emitters of two external power transistors which are connected to the windings of the DC motor. In this manner, a relatively inexpensive integrated circuit can be used to drive and control a DC motor having a much higher operating voltage.
    Type: Grant
    Filed: June 2, 1992
    Date of Patent: May 3, 1994
    Assignee: Nidec Corporation
    Inventors: Elmer W. Madsen, Phep X. Nguyen
  • Patent number: 4791519
    Abstract: An immersion detection current interrupter circuit with an electric latch for use in small electrical appliances. A sensor wire is positioned within an appliance to sense current leakage when in contact with a conductive fluid. A relay or solenoid connected to the sensor is positioned between the load leads in a latch circuit. When the sensor detects a leakage current, it causes a two-pole double-throw relay to latch, breaking the load lines beyond the relay. The relay will remain latched until the power cord is unplugged or reset by a switch which opens and closes the power lines. Once the component has latched, the maximum leakage current will be limited by the voltage drop across a diode.
    Type: Grant
    Filed: September 11, 1987
    Date of Patent: December 13, 1988
    Assignee: North American Philips Corp.
    Inventor: Elmer W. Madsen
  • Patent number: 4712154
    Abstract: A shock protection circuit utilizing an immersion detection current interrupter for use in small electrical appliances wherein the combination of a solenoid or a relay plus a sensor will cause an interruption of the power leads of a small appliance and the mechanical latching of the relay or solenoid contacts in an open position when the presence of an electrically conductive fluid is detected. In one embodiment, the sensor remains conductive at a safe level, while in a second embodiment power to the sensor is also interrupted. Both embodiments are immune to electrical noise.
    Type: Grant
    Filed: June 27, 1986
    Date of Patent: December 8, 1987
    Assignee: North American Philips Corporation
    Inventor: Elmer W. Madsen
  • Patent number: 4672247
    Abstract: A hybrid stepper motor having two alternately excited magnetic systems, one providing positions of 0.degree. and 180.degree., and the other positions of 90.degree. and 270.degree.. To minimize position offset due to unequal flux through the two air gaps of the unexcited system, a nonmagnetic space is provided to reduce the relative difference in reluctance between the magnetic paths which include the two air gaps of the unexcited magnetic system.
    Type: Grant
    Filed: December 31, 1985
    Date of Patent: June 9, 1987
    Assignee: North American Philips Corporation
    Inventors: Elmer W. Madsen, Ping-Shih Wang
  • Patent number: 4128825
    Abstract: A magnetically actuated indicator includes a housing carrying an elongated permanent magnet for pivotal motion about a geometric axis which extends transversely to the geometric axis of the magnet. First and second poles are carried by the housing and are disposed in spaced relationship to each other and each is proximate to one end of the elongated permanent magnet in one angular position thereof. A coil is magnetically linked to the poles to change the polarity thereof and a stop prevents positioning of either end of the permanent magnet intermediate the two poles to insure consistant indications.
    Type: Grant
    Filed: December 13, 1976
    Date of Patent: December 5, 1978
    Assignee: North American Philips Corporation
    Inventor: Elmer W. Madsen
  • Patent number: 4081703
    Abstract: An electric motor having a stator with a plurality of pole pieces which are disposed in angularly spaced intervals about the axis of rotation of a cooperating rotor. Each stator pole piece has one or more teeth thereon. Each tooth has an inner peripheral surface which lies on the circumference of a circle having its center on the axis of rotation of the rotor. The teeth on each stator pole piece (which has a plurality of teeth) are spaced with a uniform pitch therebetween and the pitch on one stator pole piece is the same as the pitch on any other stator pole piece. One of the stator pole pieces and an adjacent stator pole piece about the axis of the rotor comprise a pole pair. Each two successive stator pole pieces disposed about the axis of the rotor comprise additional pole pairs.
    Type: Grant
    Filed: May 26, 1976
    Date of Patent: March 28, 1978
    Assignee: North American Philips Corporation
    Inventors: Elmer W. Madsen, Charles W. Hansen
  • Patent number: 4059024
    Abstract: A gear train includes a plurality of gears mounted for cooperation. Two of the gears are provided with at least one projection from the side of the gear in a direction generally parallel to the axis thereof. In operation the projections on the gears interfere at a predetermined angular position to limit movement of the gear train.
    Type: Grant
    Filed: November 12, 1976
    Date of Patent: November 22, 1977
    Assignee: North American Philips Corporation
    Inventors: Elmer W. Madsen, George B. Soden