Abstract: A ballast circuit for a discharge tube such as a fluorescent tube, mercury vapor, sodium vapor or metal halide lamp is disclosed. D.C. power is provided alternately between two output driver stages and an a.c. neutral return line. In output transformerless (OTL) embodiments of the invention, a series connection of a reactance circuit and the tube is connected between the push pull point and the a.c. neutral return line. In transformer embodiments of the invention, a primary winding of a transformer is connected in series with the reactance circuit. The tube or load is connected across an output winding of the transformer with the electrical effect that the load is in series with the reactance circuit. Alternative arrangements of transformer input windings are provided. The first includes two input primary windings wound in opposite directions with the circuit arranged such that current flows in one or the other of the input transformer windings on alternating half cycles of the control signal.

Abstract: A constant power supply unit of an electric heating apparatus is disclosed. A voltage sensing circuit generates a DC reference signal corresponding to the nominal value of an AC supply voltage. A timing pulse generator generates a rectangular waveform signal during one of every four cycles. A trigger generator generates a trigger signal at zero-cross points determined by the combination of outputs of a voltage sensing circuit and the timing pulse generator. A power control circuit controls the input power to the electric heating apparatus by the trigger signal, thereby allowing a constant power supply to the electric heating apparatus regardless of the nominal value of the AC supply voltage which may be either 220 volts or 100 volts.

Abstract: The problem of effectively and quickly detecting fault conditions in an electromotive machine (10) is solved using a current transformer assembly (28) having a neutral lead (44). The neutral lead (44) comprises a single piece copper strap (80) having laterally extending strips or posts (81-83) provided for connection to the neutral end conductors (31-33) of armature windings (22 and 24). The strap (80) is punched and bent into shape to include the three neutral posts (81-83). Each neutral post (81-83) carries a current transformer (46-48).

Abstract: A superconductive ring or coil is irradiated with a light ray so that its superconducting state is destroyed for a short period of time. Under the destruction of the superconducting state, removal of energy from the superconductive ring or coil or storage of energy therein is stably controlled.

Abstract: An integrated drive generator (40) for generating constant frequency alternating current which is driven by a drive shaft (12) at variable rotational speeds includes an alternating current generator (23) having a rotor (37) mounted on a first shaft (42), which is driven by an output of a constant speed drive (14) at a fixed rotational velocity, the constant speed drive also driving a second shaft (44) at a fixed rotational velocity; an exciter (20) having a rotor (32) mounted on the first shaft, electrically coupled to a field winding of the generator, for supplying electrical power to the field winding of hte alternating current generator; and a permanent magnet generator (18) having a rotor (24) mounted on the second shaft, electrically coupled to the exciter, for supplying electrical power to a field winding of the exciter. Using the second shaft reduces weight, as well as length.

Abstract: A circuit arrangement for feeding a load (3) from a low voltage energy source (1) via a direct-voltage conversion circuit (2). The direct-voltage conversion circuit periodically takes energy from the energy source by means of a main switching element (10) and supplies this energy as an increased supply voltage (at 12) to the load via an inductive element (9) and a rectifier (11). A starting switching element (15) takes energy for generating the supply voltage (at 12) from the energy source during a starting phase. The circuit arrangement is simple and compact and the energy losses produced are so low that it is economic to use it for energizing a small appliance particularly a small domestic appliance, from a battery or a rechargeable accumulator. A main control circuit (13) is supplied with energy directly from the supply voltage (at 12) and periodically controls the main switching element.

Abstract: An element that moves resonantly has its resonant frequency dynamically tuned to a desired frequency by two components that cooperate via magnetic fields, one component being mounted for motion with the moving element.

Abstract: A dynamoelectric machine having a large magnetic gap between the rotor and the stator includes a slotless stator windings located within the large magnetic gap, and a mgnetic assembly consisting of radially aligned permanent magnets separated by non-magnetic material. The magnetic pole circumferential length and the radial gap length are proportioned such that the permanent magnets are operated at or near their maximum energy product.

Abstract: The electric motor contemplated by this invention includes an armature having two opposed faces mounted on a shaft. The armature is mounted on the shaft intermediate of the ends of the shaft. A pair of commutators are mounted on the shaft adjacent to each of the opposed armature faces. Each of the commutators includes a plurality of commutator bars, each of which has its circumferential width offset relative to the circumferential width of the commutator bars on the other commutator. Alternately or in combinatrion, with the commutator bar offset the brushes in operative engagement with each of the commutators are arranged with their circumferential width offset, relative to the circumferential width of the brushes in operative engagement with the opposite commutator. The electric motor can also be provided with a redundancy capability by a circuit arrangement in which one of the commutators is held as a backup in the event of a failure of the windings of the other commutator.

Abstract: Control apparatus of the kind disclosed in UK patent specification Nos. 2,073,887 and 2,114,717, i.e. in which a movable operating member, arranged to control associated apparatus such as an aircraft engine, is coupled to an electric stepper motor, the motor being energizable to move the operating member and/or to generate a `feel` resistance to, or detents in, the manual movement of the operating member, the apparatus including a ball-screw assembly comprising a lead-screw and ball-nut, one of which is connected to the operating member and, with the operating member, is linearly movable with respect to the other, the stepper motor being coupled to the ball-screw assembly so that rotation of the motor rotor produces, or is produced by, relative rotation of the lead-screw and ball-nut.

Abstract: A three phase two-pole induction motor includes a three phase winding wound as a two-pole winding with an effective full pitch wound winding connected in a double delta connection. Each pole group includes a plurality of coils wound as a concentric winding or as a short pitch lap wound equivalent winding. A 36 slot stator is illustrated and includes each phase winding wound with 2 coil units each having 2 coil groups. Each coil group has 3 concentric coils and in the illustrated concentric winding the one phase winding has one group with coil sides in slots 1-3 and 16-18 and the second group in slots 19-21 and 34-36. The next phase winding has similar coils in slots 4-6 and 25-27 and in slots 7-9 and 22-24. The third phase winding has similar coils in slots 10-12 and 31-33 and in slots 13-15 and 29-30. The coil sides of each of the two groups are connected to form a full pitch winding.

Abstract: A variable reluctance motor having untapered stator teeth and more rotor teeth than stator teeth. Two stator teeth are formed on each stator pole. The rotor tooth ratio (of tooth width to gap between teeth width) is equal to the stator tooth ratio for the two teeth on each stator pole. The rotor tooth ratio is in the range of about 0.70 to about 0.90, preferably about 0.78. With this configuration the motor has very low torque ripple. The stator teeth are magnetically saturated, so the motor can be operated at current levels above the saturation point, producing a linear torque to current function and high output torque.

Abstract: A voltage converter (100) converts a high voltage, low frequency input to a low D.C. voltage output. The input is rectified to facilitate the operation of an oscillator (202) which operates alternately a pair of MOSFETS (124 and 126).Upon operation of MOSFET (124), the intermediate D.C. voltage is applied across and directs current in one direction through a primary winding (132) of a high frequency step-down transformer (134) and also charges a series-connected capacitor (152). Upon operation of MOSFET (126), capacitor (152) discharges to provide current through primary winding (132) in the opposite direction. In this manner, an alternating voltage at a high frequency is stepped down to a secondary winding (142) of transformer (134) and is rectified to provide the low D.C. voltage output.Diodes (120 and 122) prevent undesirable oscillations within voltage converter (100) if a short should occur in any load connected to the output of the converter.

Abstract: A current limited DC power controller is provided with an output stage having a controllable solid state switching device for conducting current between a pair of output terminals and a drive circuit for controlling the operation of this switching device in response to a control signal. A programmable current source is used to produce a reference current signal in response to a command signal and this reference current signal passes through a resistor to produce a reference voltage signal having a magnitude proportional to the command signal. When the power controller is off, the reference voltage signal is clamped to a preselected value. A second voltage signal proportional to the load current is combined with the referenced voltage signal and used to produce the control signal to which the drive circuit responds.

Abstract: A power supply control circuit, for control of the power supply, controls a solid state relay in series with the power input to the power supply. The power supply control circuit also generates control signals, indicating pending power failure, for the microcomputer arranged in a card cage.

Abstract: A parallel conducting ring structure for a dynamoelectric machine is configured to be mounted as a subassembly upon a conventional support cone for wholesale installation through an opening formed in an axial end of the casing structure surrounding the stator core of a dynamoelectric machine. Tab connections are attached, at preselected locations about the axis of the stator core, to the parallel conducting ring structure and are insulated with conventional groundwall insulation. Depending upon the particular direction of rotation of the rotor and upon the direction in which the generated electromotive forces are to peak, each direction of which is selected by the utility, the subassembly is installed within the casing structure through the opening, and adapted for such particular directions by stripping the insulation from selected ones of the tab connections, attaching the main leads exiting the casing structure to such tab connections, and leaving the remaining ones of the tab connections insulated.

Abstract: A rotor assembly comprises a high energy product permanent magnet contained within a sheath and metallurgically bonded thereto. The metallurgical bond imparts mechanical strength to the magnet, thereby preventing crack propagation therewithin during operation of the rotor assembly, and minimizes the thermal barrier to the transfer of heat from the magnet to the sheath.

Abstract: A current source is controlled by the output signal from a digital to analog converter. The output signal from the digital to analog converter is applied to an amplifier unit. The output of the amplifier unit controls current through a pass transistor element, the pass transistor element current being the current applied to the load impedance. A feedback signal is generated by a differential amplifier in response to the current applied to the load impedance. The output signal from the difference amplifier is applied to an input terminal of the digital to analog converter with a polarity resulting in a change in the output signal of the amplifier unit which compensates for any change in the current through the load impedance. A voltage level changing element is included in the pass transistor control terminal to interrupt the current to the load impedance in the event of a degradation in the power supply.

Abstract: A disc-type motor characterized by increased efficiency includes first and second parallel spaced stator members made of magnetic material in fixed relation, each of the stator members having a flat circular shape and an even plurality of pie-shaped permanent-magnet poles thereon, illustratively eight in number. The facing poles on the stator members have opposite polarities. The motor further includes a disc-like rotor made of a non-conducting material rotatably mounted between the two stator members. Conducting wires are wound in a non-overlapping (single-layer) flat spiral configuration to form a number of coils equal to twice the number of poles per stator member, half adhered to each face of the rotor disc. Each coil encloses a pie-segmented area about equal to the area of one of the stator poles. On each face of the rotor the coils magnetically oppose one another, and the coils on one face of the disc are angularly offset from the coils on the other face of the disc.

Abstract: Electric motor with a substantially cylindrical air gap between the stator and the rotor, the stator being fitted to a bearing support for the rotor shaft bearing. In order to reduce noise emissions, the stator is connected to the bearing support by means of an elastic damper and the stator and bearing support are separated from one another by an air gap adjacent at least part of their facing faces.