Abstract: A device for controlling an A.C. motor having an electromagnetic field ining coil wound around a conductive element having at least one inwardly directed opening bound by surface areas thereof and having a gap a between the surface areas defined by the formula a .gtoreq. .delta., wherein .delta. is the wave penetrating depth of an instantaneous operating frequency of the induced electromagnetic energy, the coil being wound so as to surround the open space and the element.

Abstract: A weight measuring apparatus, wherein a weight sensitive element is connected to a metallic moving member of a weight sensitive element displacement-to-electrical inductive transducer. The moving member is made as a plate positioned in the clearance between two inductance coils of said transducer secured on the casing, their windings being arranged on armour cores. The winding of the first inductance coil is connected to a high-frequency oscillator, whereas the winding of the second inductance coil is electrically connected to a metering circuit. The weight measuring apparatus is characterized by high accuracy of measuring, quick action and high resolution.

Abstract: A rotation indication system having an improved sensing device for determining the velocity of a rotating body is disclosed. The improved sensing device is tubular in configuration and includes a source of magnetic flux and two pole pieces that define a split magnetic field. The sensing device is mounted in close proximity to a rotor which is connected to the rotating body. The rotor has apertures which interrupt the split magnetic field producing an output signal with a frequency proportional to the velocity of the rotating body. The sensing device is oriented relative to the rotor apertures so that each pole piece is alternatively in register with an aperture to produce the desired output signal. Since the sensing device is tubular in shape, it can be rotated about its axis to obtain the desired orientation with the rotor apertures, thus permitting the use of the sensing device with a wide range of rotor diameters having various aperture spacings.

Abstract: An electrical transformer comprises a core structure formed from magnetizable material and comprising a first annular element in the peripheral surface of which is formed at least a pair of helical slots. The core structure includes a second element which closes the open ends of the slots and located in each slot is at least two windings forming the primary and secondary windings of the transformer. Each winding extends along one slot and returns along the adjacent slot.

Abstract: A variable inductor wherein two closed magnetic circuits each having a predetermined gap in one place are constructed of a movable magnetic core and a fixed magnetic core. When the movable magnetic core is moved, the opposite area between both the magnetic cores in one of the closed magnetic circuits increases, while the opposite area between both the magnetic cores in the other closed magnetic circuit decreases. Thus, the inductances of coils wound around parts of the respective closed magnetic circuits vary complementarily.

Abstract: A transformer designed to operate with a pair of power switching transistors in a d.c. to a.c. inverter is described. The transformer has an assembled core whose closed magnetic path is branched. A flux steering winding is used to ensure the prior saturation of a first branch associated with a regenerative feedback winding. Prior saturation of this branch reduces the forward drive on the switching transistors prior to full core saturation and avoids the consequent switching stresses on the transistors. The cores of the transformer are made from parts which abut at the branches so that both preformed power and preformed control windings may be used in assembling the transformer. The transformer may be assembled from conventional core configurations, and is thus of relatively low cost. A core arrangement is also disclosed in which the cross-section of the individual branches of the core may be adjusted.

Abstract: A sewing machine is disclosed having electromechanical actuators for controlling the stitch forming instrumentalities in the formation of stitch patterns with a non-contact position sensing device associated with each electromechanical actuator comprising spaced coils and a metallic shunt plate arranged adjacent and shiftable relatively to the coils in response to movement of the actuator to produce a measureable variation in the inductance of the coils which bears an advantageous linear relationship to the electromechanical actuator position.

Abstract: An angular position transducer includes a core of magnetic material of circular shape and having a central hub extending from a central portion of and opposite outer rims extending from the outer periphery of a disk-shaped web. An armature which is of like size and shape to one half of the core so as to be semi-circular in configuration is mounted so as to undergo rotation relative to the core, the single outer rim of the armature being disposed adjacent one or the other or both of the outer rims of the core. A primary winding wrapped around the central hub of the core produces magnetic flux which flows into the armature, then through the single outer rim of the armature and adjacent portions of the outer rims of the core to a pair of secondary windings wound around the web of the core on opposite sides of the hub.