Abstract: A modification of the squirrel cage of an alternating current motor reduces the starting current amperage. A conventional motor squirrel cage, which includes rotor bars and shorting rings, is modified so that the cage may have two or more controllable resistance values by segmenting the shorting rings. A high resistance cage is obtained for initial motor starting when the open segmented shorting rings provide a high resistance path within the squirrel cage circuit. Subsequent to the motor's attaining full rotation speed, a low resistance value of the squirrel cage is achieved by shunting the segmented shorting rings, which gives the motor its optimum running efficiency. In one embodiment, a mechanical means is used to accomplish the shunting of the shorting rings. In a second embodiment, a solid state control device is used to accomplish the shunting of the shorting rings.

Abstract: A motion conversion device has actuator sets attached to a housing, the housing surrounding a rotary actuator. Each actuator set includes an actuator and an elastic mechanism to contact the rotary member so that it may be driven. The device changes micro amplitude oscillatory motion into continuous rotary or straight line motion. The rotary actuator can have a wavy shape.

Abstract: An induction motor, including a single rotor formed in one-piece and first and second stators disposed side by side, has a phase changing device for varying the phase difference between the rotational magnetic field generated by the first stator and that generated by the second stator. The phase changing device comprises at least first and second short-circuiting switches for short-circuiting or disconnecting the series-junction nodes of the stator windings. The first switching produces a configuration intermediate to series delta and parallel Y (Wye), and the second completes the transformation from delta to Y. The motor presents three different torque curves suitable for starting operation, intermediate speed operation and normal or steady-state operation by the switching operation of the first- and second-switches.

Abstract: A homopolar rotary dynamoelectrical machine used as motor or generator has a dense magnetic flux area and sparse magnetic flux area in the air gap between the confonting pole of the main field yoke, the sparse area being in a by-pass yoke which is positioned closely adjacent the side face of the confronting pole. Thus magnetic flux affecting the conductive member becomes diluted in the area of the by-pass yoke, and in the area where the by-pass yoke is not positioned, the magnetic flux affecting the conductive member is kept as it was. Accordingly, generation due to the difference in the amount of magnetic flux is possible.

Abstract: A magnetic bearing device that incorporates a magnetic movable member, a first supporting member having a first coil and a permanent magnet, a second supporting member having a second coil and a permanent magnet, state detecting means for detecting the displacement of the movable member, a first and second wirings for applying current, and switches connected to the first and second wirings for switching the direction of current applied to the first and second coils. The first and second supporting members are located so as to position the movable member between them. During operation, the movable member is magnetically supported so as not to be in contact with either of the supporting members. The first wiring has a first switch circuit connected to a first drive circuit, wherein the bottom end of the first coil is connected between the first switch circuit and the first drive circuit. The first and second wirings are connected in parallel between a dc power source and ground.

Abstract: An automatic door protective device for returning an overhead door to the open position when it encounters an obstacle as it is closing. The protective device of this invention includes a motor having an output shaft and a driving gear mounted on the shaft. A driven gear is in mesh with the driving gear mounted on a gear shaft which also mounts a worm. A worm wheel is in mesh with the worm which is mounted on a worm wheel shaft, which also mounts a pulley that raises and lowers the door in response to rotation of the output shaft to the motor. The end of the gear shaft is spaced away from a copper leaf spring, and an electrical contact is also provided spaced away from the leaf spring. The spring and the contact are part of an electrical circuit with a signal controller coupled to the motor. When the door encounters an obstacle and the pulley ceases rotation, the torque of the motor causes the gear shaft to displace axially as the worm moves along the worm wheel teeth.

Abstract: An electromagnetic clutch includes a clutch rotor having a first friction surface and an annular armature plate having a second friction surface. The first friction surface and the second friction surface face each other. A friction member made of nonmagnetic material is fixedly disposed within a second groove formed at the second friction surface of the annular armature plate. A first end surface of the friction member projects with respect to the second friction surface of the annular armature plate. The first friction surface of the clutch rotor is provided with a first annular groove to receive the projecting portion of the friction member. Therefore, the depth of the second groove becomes smaller. Consequently, the number of magnetic lines of flux which radially penetrate through an annular portion of the annular armature plate at the location of the second groove is enhanced.

Abstract: A variable braking force electric brake for materials handling vehicles, such as fork lift trucks, utilizes two sets of springs to urge brake pads against a rotor of a disc brake. The first set of springs provide a first level of braking force, typically one-third of the total braking force. The second set of springs provide a second level of braking force, typically two-thirds of the total. A pair of electromagnetic elements act on armatures placed between the springs and a non-magnetic brake pad support plate to selectively permit either the first set of springs alone to provide braking, the second set of springs alone, or both sets together. Initially, the current to the electromagnetic elements is strong, to insure that the associated armature is pulled toward the electromagnet, and afterwards, the current is reduced to minimize heating and power requirements.

Abstract: An electromagnetic actuator varies the cross-sectional area of a passage of damping oil in a variable damping force shock absorber. The wires leading from coils of the actuator are led through a groove formed between the edge of an opening formed in a housing and an outer peripheral portion of the cover, the groove being charged with a binding resin, whereby the watertightness of the actuator is maintained for a longer time and the assembly of the actuator is facilitated.

Abstract: An electrostatic actuator includes a stationary element and a movable element. The stationary element has a surface which faces a surface of the moving element. Both the surface of the stationary element and the surface of the moving element have electrode lines disposed thereon, including a first set of parallel electrode lines and a second set of parallel electrode lines which are perpendicular to the lines in the first set. By facing the stationary surface and the movable surface towards each other such that the electrode lines of such surfaces are aligned, the movable element can be moved along either of two perpendicular axes when a voltage is applied to the electrode lines.

Abstract: Electrical terminal pins (start, main and common) mounted in a glass header to provide electrical connection to a compressor motor are shown with a motor protector disposed on one of the pins in such a fashion that opposite-direction-oriented right angle female flag quick connectors are required for the start and main terminals, thereby avoiding the possibility of miswiring the terminal pins. The opening temperature of the motor protector is adjustable and the protector has a fail safe mechanism to avoid subjecting the motor to overtemperature conditions.

Abstract: A high precision linear actuator includes high fidelity mechanical linkages between the motor drive and the linear displacement output shaft. Rotational motor drive output is conveyed to a rotatable spindle (20) and lead nut assembly by means of belt driven sprockets. Rotation of the lead nut assembly is converted to linear displacement of a non-rotating lead screw and output shaft. Linear actuators of the present invention also incorporate a feedback control feature employing Moire fringe pattern techniques to continuously monitor the position of the output shaft.

Abstract: A thin, metallic sensor ring for rotational sensing systems wherein protrusions formed on the periphery of the ring are constructed so as to interrupt an electromagnetic flux emitted by a sensing device mounted in fixed relation to the ring, whereby rotation of the ring may be detected. The protrusions are formed without removing any metal from the ring, preferably by a stamping or drawing operation. Slits may be provided in the ring to facilitate the formation of the protrusions. The ring may be partially encapsulated in a plastic mounting adapter to facilitate mounting thereof on a rotating shaft or hub.

Abstract: An electric motor includes a heat spike within the stator slots which extends radially inward from the stator back iron into the slot between the stator teeth. The heat spike, placed within the stator slots, reduces the heat path length and increases the heat transfer areas to the iron. Together, these allow the winding heat to dissipate quicker, and thereby, reduce the hotspot temperature and improve the motor's load rating.

Abstract: An induction motor including a single rotor formed in one-piece and first and second stators disposed side by side has a phase changing device for varying the phase difference between the rotational magnetic field generated by the first stator and that generated by the second stator. The phase changing device comprises a first-connection changing switch for making the interconnection of respective stator windings of the stators the first series delta-connection in which the phase difference is 0.degree. when it is in its closed-state and a second-connection changing switch for making the respective stator windings the second series data-connection in which the phase difference is 120.degree. when it is in its closed-state. When both the first- and second-connection changing switches are closed, the interconnection of the stator windings becomes a parallel Y (or star)-connection in which the phase difference produced is 60.degree..

Abstract: A combination air load and magnetic load device applies load to a rotor of an exercise machine. The rotor includes a fan wheel and an eddy current disc. A non-rotating magnet plate faces the eddy current disc and is spaced from it by an air gap. The non-rotating magnet plate includes a circumferential array of permanent magnets, their polarity orientations alternated. The eddy current load is variable by manual or automated control of the air gap between the eddy current disc and the non-rotating magnet plate. The user can reduce the load by increasing the air gap, or increase the load by decreasing the air gap. The rotating fan wheel generates air movement for cooling of operator and equipment, and a corresponding fan load on the rotor. The rotating eddy current disc induces an eddy current load on the rotor.

Abstract: A magnetic bearing has a number of pole pieces disposed about the circumference of the shaft supported by the bearing. To inhibit magnetic flux migration within the bearing, magnetic barriers of non-magnetic material are interposed between pole pieces at selected locations. Magnetic guides prevent magnetic saturation of the bridging portion of the pole pieces prior to the poles' saturating.

Abstract: Noise and vibration in a structure are reduced through application to the structure of an oscillatory torque. An electromechanical energy converter provides the oscillatory torque when the input signal to the electromechanical energy converter has a frequency and harmonics thereof required to counteract the noise and vibration desired to be attenuated.

Abstract: A brushless dc linear actuator includes a guide rail which extends in a longitudinal direction, and at least one moving member such as a slide, each of which is movable along the guide rail in the longitudinal direction. Each moving member includes permanent magnets. Rail supports are provided for each end of the guide rail and for holding the guide rail substantially horizontal. The moving member is propelled electromagnetically forward and backward along the rail by sequential activation of at least one series of electromagnetic coils distributed longitudinally with a predetermined pitch. A Hall-effect arrangement, including one Hall-effect element adjacent to each coil, provides non-impulsive, gradual activation and shut-off of active ones of the coils within a predetermined distance of the permanent magnets of the moving member. The pitch of the coils is determined as a precise function of the width of the permanent magnets, a phase simulation constant, and a coil selection constant.

Abstract: The synchronous motor has a pick-up (C) measuring the position of its rotor and a power-varying circuit (VP) operating as a current generator. A power-varying circuit (VP) is controlled by a programmed microprocessor (MP) receiving information specifying the desired speed for the motor (M), information representative of the difference between the current speed and the desired speed for the motor, information from said pick-up relating to the position of the rotor of the motor, and stored information in order to enable it to force zero phase difference between the current I delivered by the power-varying circuit and the potential difference U across the terminals of the motor windings, thereby minimizing the installed power required of the power-varying circuit in order to run the synchronous motor and power-varying circuit at constant power. A control system operates the motor at constant power.