Abstract: A normally closed AC relay with a stator core with primary and shaded poles, a pivotal clapper, an elongated leaf spring fixed to the clapper providing a clapper return spring and a clapper overtravel spring extending radially outwardly from the outer end of the clapper, the overtravel spring being substantially narrower than the rest of the leaf spring to reduce the weight and moment of inertia of the overtravel spring and the complete clapper assembly, the overtravel spring having a spring rate significantly greater than the return spring and both the overtravel spring and clapper assembly having a natural frequency significantly greater than twice the frequency of the AC source so that the clapper is actuated to open the relay without incipient switch chatter.

Abstract: A normally closed AC relay having a stator core with primary and shaded poles, an operating coil mounted on the stator core to magnetically attract a pivotal clapper in one pivotal direction thereof toward the stator pole against the bias of a return spring, the clapper and/or stator core having a reduced transverse section in the magnetic loop of the operating coil with a cross-sectional area equal to or less than that of the primary pole to control the magnetic field across the working air gap by magnetic saturation of the reduced section.

Abstract: In a sensor for sensing current in a conductor, a magnetic laminar arrangement adapted to surround the conductor passes through a coil. Inside the coil the laminar arrangement forms a gap with two projections extending transverse to lamina within the arrangement and facing each other. In one embodiment the coil drives a display to form part of a fault indicator.

Abstract: A sensor in a faulted current indicator includes a coil and a magnetic arrangement passing through the coil and around a current-carrying conductor for coupling the coil to the conductor. The magnetic arrangement has given magnetic reluctance and forms a higher reluctance section, such as a gap, within the coil. Preferably the magnetic arrangement includes a U-shaped laminate and two core laminations joined to the U-shaped laminate by two gaps to allow for installation around the conductor. The ferromagnetic plate outside the coil shields the coil. The sensitivity of the sensor is increased by coating the inner surface of the U-shaped laminate and the core lamination surfaces contacting the U-shaped laminate with a high Ni content ferromagnetic material.

Abstract: In the disclosed device, a pair of magnets supported in the ends of a C-shaped yoke bias an armature into one of the two rotary positions. A short pulse to a coil about the center of the yoke induces a short term magnetic field that supplements the polarity at one end of the yoke so as to either maintain the armature in its biased position or swing the armature to its other biased position. A subsequent pulse, producing a field in the opposite direction, returns the armature to its first position. In each case, the magnets retain the armature in its biased position even after the pulse stops. The armature pivots between portions of the yoke magnetized by the same magnet.

Abstract: A vane-type galvanometer employs a stator having a unibody type structure. Narrow bridge regions of the stator are magnetically saturated to produce regions of high magnetic reluctance and salient magnetic poles in the stator. A pre-wound bobbin is mounted to the stator for generating a control flux to thereby exert a torque on a vane armature.

Abstract: The electric motor includes a mover, which may be a rotor or actuator, and a stator having a number of poles projecting toward the mover. The poles have soft-magnetic teeth projecting toward the mover and extending transverse to the direction of mover movement, and the mover has soft-magnetic teeth projecting toward the stator teeth and extending transverse to the direction of mover movement. Windings energize the stator to move the mover. Dividing each pole transverse to the direction of mover movement to define two pole portions per pole, and locating permanent magnetic material between stator teeth in only one portion of each of the poles, enhances the motor torque while achieving a saving of permanent magnetic material. Preferably the magnetic material exists on alternate pole portions in successive poles.

Abstract: Iron surfaces of stator poles, rotor periphery, or both stator poles and rotor periphery, of stepping motors are manufactured without teeth. The stepping effects of teeth are obtained by bonding, to the toothless surfaces, webs composed of fluted magnetic material having alternate thin and thick sections magnetized in the direction of the thickness of the material and carrying soft magnetic inserts in the flutes. The inserts form virtual teeth. The thick sections are magnetized in the direction opposite to the thin section and the flutes extend in the direction transverse to the direction of relative motion between rotor and stator.

Abstract: An electromagnetic counting mechanism having a rotary counter and an electromagnetic operator with a pivotal clapper adapted to be magnetically actuated for indexing the counter. The clapper has a primary air gap and a tangential projection which cooperates with an edge of a pole of the electromagnet to provide a secondary air gap to reduce the rate of increase of magnetic force as the clapper is pivoted to its closed gap position and so that the magnetic force/clapper displacement curve has a generally flattened slope less than that of the return spring force/clapper displacement curve for stable pivotal operation of the clapper with a shaped drive pulse.

Abstract: A rotary electromagnetic indicator having a stator with an annular arrangement of five equiangularly spaced radially inwardly extending salient poles, a winding on each stator pole and an indicating rotor having a permanent magnet with diametrically opposed north and south salient poles, each having an angular width equal to the included angle of a pair of adjacent salient poles of the stator.

Abstract: A clock with a rotary drive motor having a pair of axially aligned stator subassemblies with identical molded frame parts with interfitting end portions rotatably supporting a permanent magnet rotor and take-off gears. A separate axially extending U-shaped pole piece is mounted on each frame part to provide four stator poles equiangularly spaced about the axis of the rotor, and each frame part forms a coil bobbin for winding a stator coil for the respective pole piece.

Abstract: An electromagnetic counter with a rotary counter and an electromagnetic operator for indexing the counter having a generally U-shaped core plate mounted in opposed pockets in parallel end supports of a plastic support frame, an energizing winding on one of the parallel legs of the core plate, and a pivotal actuator connected for indexing the counter having a ferromagnetic armature member positioned aside and extending transversely of the parallel legs of the core plate. A ferromagnetic insert having a preselected configuration and permeability is inserted through a slot in the support frame and press fit between the parallel legs of the core plate to provide a saturable magnetic shunt for preventing electromagnetic operation of the counter by electrical noise spikes of relatively short duration and to provide an air gap filler for reducing the incipient air gap of the electromagnet.