North American Philips Corporation

Nidec Corporation

Elmer W Madsen

Phep Xuan Nguyen

Charles W Hansen

Ping-Shih Wang

George B Soden

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.

Drive and control circuit for a brushless DC motor

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.

Shock protective circuit with electrical latch for small appliances

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.

Shock protective circuit with mechanical latch for small appliances

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.

Synchronous or stepping motor with equal-torque stepping

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.

Magnetically actuated indicator

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. The plurality of teeth on one of the stator pole pieces in each of the pole pairs is shifted with respect to the plurality of teeth on the other stator pole piece in the same pair one half of the tooth pitch and the plurality of teeth on the adjacent pole pieces of adjacent pairs of stator pole pieces are shifted 1/2N of a tooth pitch where N is the number of phases of the motor.

Electric motor having toothed pole pieces

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.

Growing community of inventors

Bristol, CT, United States of America

Elmer W Madsen