Abstract: A slotless motor has a sufficiently small gap between a stator and a rotor, and improves characteristics of the torque and the power factor. Accordingly, the slotless motor comprises stator cores having no slots, coils forming revolving magnetic fields in the stator cores, and rotors having a permanent magnet. The coils are disposed along the stator cores cylindrically and constructed in one layer. Each of the coils forms a part which decreases the distribution of the number of turns in the direction of a diameter of the stator cores, and adjoining coils pile on each other at the part in the direction of the diameter of the stator cores. The distribution changes in response to a predetermined range.

Abstract: A magnetic slot wedge inserted in each slot of a stator core of a dynamo-electric machine so as to close an opening of each slot for preventing coils embedded in each slot from getting out of each slot is disclosed. The slot wedge includes a first thin non-magnetic sheet such as a polyester film having the thickness of several ten microns or an aromatic aramid paper, an amorphous sheet bonded to one of two faces of the first non-magnetic sheet opposite the other face facing a coil side in the condition that the wedge is inserted in each slot, and a second thin non-magnetic sheet bonded to the amorphous sheet so as to cover it. Each non-magnetic sheet has such dimensions that each non-magnetic sheet is projected from both ends and both side edges of the amorphous sheet.

Abstract: A slot insulating magnetic wedge inserted into the vicinity of the center of an opening portion of a stator slot, the slot insulating magnetic wedge being contacted with an inner surface of the stator slot of a motor. The slot insulating magnetic wedge comprises a non-magnetic insulating thin leaf shaped material and a magnetic material layer laminated on at least one surface of the non-magnetic insulating thin leaf shaped material, the electric resistance of the magnetic material layer being in the range from 10 .mu..OMEGA..cm to 200 .mu..OMEGA..cm. The magnetic material layer comprises an amorphous magnetic alloy thin film, a Fe-based magnetic alloy thin ribbon having ultra fine crystalline particles, a crystalline magnetic alloy thin ribbon, a crystalline or amorphous magnetic alloy thin film produced by thin film forming technologies, or the like. The magnetic material layer with the electric resistance in the range from 10 .mu..OMEGA..cm to 200 .mu..OMEGA..

Abstract: A squirrel-cage rotor includes a rotor core composed of steel sheets. Each steel sheet has in the outer circumference a number of slot-forming punched portions along the outer circumference thereof, each punched portion including a main portion and an additional portion inclined toward one of two sides along the outer circumference of the rotor relative to the position of the main portion, such that each punched portion has an unsymmetrical shape. The units include those formed by laminating the steel sheets having the respective additional portions inclined in the direrction of one side, and those formed by laminating the steel sheets having the respective additional portions inclined toward the other side. Slots are formed so as to be parallel with the rotor axis.

Abstract: A magnetic core employed in AC motors, transformers and the like includes a first core portion formed by laminating silicon steel sheets each containing 3.5% silicon, the first core portion having two ends in the direction that the sheets are laminated, and second core portions disposed at the respective ends of the first core portion and formed by laminating silicon steel sheets each containing 6.5% silicon. In distorted wave alternating field, low frequency fluxes pass through the first core portion and harmonic fluxes pass through the second core portions. Since each second core portion has a low level of magnetostriction, the magnetic noise due to the harmonics is reduced.

Abstract: A pole change type motor has armature windings wound around an iron core in a coaxial fashion with a P (for example 2) number of poles for a high speed operation, which armature windings provide a Q (for example 20) number of poles for a low speed operation by changing the external connections of the windings. Each phase coil of the armature windings is segmented into N (for example P, the same number as the poles) portions, a one-pole portion of each phase coil being comprised of a plurality (for example 2) of coils. The plurality of coils include one or more coils of which polarity is changed by changing the external connections of the armature coils and one or more second coils alternately disposed with respect to the first coils, of which the polarity is left unchanged by changing the external connections.

Abstract: An armature winding for a three-phase induction motor is provided with slots in each of which are placed windings having a double-layer structure. The number of slots, q per pole per phase is: q=z/(3.times.P), and q is less than 1/2, where z denotes the number of slots of the stator, and P the number of poles. The number of coils, Q, per phase is: Q=z/3. The coils constitute real poles of the same polarity, the number of which is also Q, and further provide one or more imaginary poles between the real poles. The coils are connected in such a way that the voltage vector of each phase is completely balanced.

Abstract: First to fourth windings are fitted in the slots of each phase of a three-phase AC motor. Those windings are connected in series to silicon controlled rectifiers (SCRs), respectively. The first and second windings having the SCRs form a first antiparallel circuit and the third and fourth windings having the SCRs form a second antiparallel circuit. Three first antiparallel circuits are connected in a delta connection. Three second antiparallel circuits are connected in a star connection with a neutral input terminal. The output terminal of the first three phase AC power supply is coupled with the input terminal of the delta circuit of the first antiparallel circuits and has a voltage lagged by .pi./2 behind the first power supply voltage. The output terminal of the second power supply of a star connection with the neutral point output terminal is coupled with the input terminal of the star circuit of the second antiparallel circuit.