Polyphase coil

Abstract: A system for producing alternating electromagnetic fields for use in theft detection and surveillance systems, including an arrangement of field-generating inductance coils for disposition on opposite sides of a passage to be monitored by the electromagnetic field produced by such coils. In a preferred such arrangement, upper and lower coils are used on each side of the passage and such coils are mutually distinct from one another and separately energizeable so as to generate separate components of a resulting composite electromagnetic field. The upper and lower coils in each such set are preferably disposed in coplanar alignment with one another but have at least portions of one coil overlapping portions of the other, so as to enhance uniformity in the resulting electromagnetic field. The array of separately-energizeable coils provides for resultant flux vector variation in the magnetic field along three mutually orthogonal axes as a function of coil drive excitation phase variation. The specification further discloses preferred coil-drive circuitry for accomplishing such purposes.

Abstract: A controlled switching system for converting the output of several photovoltaic solar arrays into a polyphase alternating electric current. Each array is utilized 100% of the time, and at any particular instant only one array or no array is feeding a particular phase. The specific line to which an array is connected is altered in a cyclic manner by the switching system to synthesize the polyphase current. Energy is not stored in the switching system, but instead is made available as polyphase electric current as soon as it is generated by the photovoltaic arrays. Each phase approximates a sine wave to an extent that is limited by the number of arrays. For the closest approximation, the arrays must be configured to have prescribed voltages and currents. Alternatively, a single array may be partitioned electrically in such a way that the desired voltages and currents are attained.

Abstract: The invention provides a technique of facilitating a coil winding work by continuously winding coils in the same direction, in a stator in which a plurality of coils constituting a coil group of the same phase are respectively arranged so as to include positions at which phases of induction voltage are different, whereby coil groups of three phases are disposed in a ring shape. A stator ( 102 ) of the invention has a structure in that a pair of coils ( 21 U 1, 21 U 4 ) and coils ( 21 U 2, 21 U 3 ) in which phases of induction voltage are identical in a plurality of coils ( 21 U 1 to 21 U 4 ) constituting a U-phase coil group ( 21 U) are set as different divided groups, the respective coils ( 21 U 1, 21 U 4 ) and coils ( 21 U 2, 21 U 3 ) in the divided group are continuously wound in the same winding direction while arranging crossovers ( 26 U 1, 26 U 3 ) respectively between the coils ( 21 U 1, 21 U 4 ) and between the coils ( 21 U 2, 21 U 3 ), the divided groups are connected in parallel, and a V phase and a W phase are executed in the same manner, whereby lead wires of three-phase coil groups ( 21 U, 21 V, 21 W) are star connected.

Abstract: An excitation system for a brushless generator includes an exciter portion having a set of polyphase exciter field windings and an additional exciter field winding disposed in a stator of the generator, a source of polyphase, constant-frequency AC power and circuitry coupled to the set of polyphase field winding for connecting the source of polyphase, constant-frequency AC power thereto at a beginning of operation in a starting mode whereby AC power is induced in an exciter portion armature winding by transformer action. AC power is further provided to armature windings of a main generator portion to thereby cause a rotor of the generator to accelerate. An autotransformer is provided to reduce the voltage provided by the source of polyphase AC power prior to application of such power to the polyphase field windings so that the need for an auxiliary inverter is obviated. Thereafter, at least one of the windings of the set of polyphase windings is connected in series with the additional field winding when the speed of the rotor reaches a predetermined speed and a DC current of controlled magnitude is delivered to the series-connected exciter field windings to thereafter allow operation in a generating mode.