Abstract: In a method for manufacturing a laminated iron core from a thin sheet, the method includes coining the thin sheet from below to form a thinned bridge portion on an outer peripheral portion of an iron core piece, blanking the iron core piece from the thin sheet from above or below after forming the bridge portion, and laminating the iron core piece on another iron core piece to manufacture the laminated iron core.

Abstract: In a method for manufacturing a laminated iron core from a thin sheet, the method includes coining the thin sheet from above to form a thinned bridge portion on an outer peripheral portion of an iron core piece, blanking the iron core piece downwardly from the thin sheet using a set of an outer-shape blanking punch and a die after forming the bridge portion, wherein the outer-shape blanking punch includes a projection portion fitted into the bridge portion when blanking, and laminating the iron core piece on another iron core piece to manufacture the laminated iron core.

Abstract: In a method for manufacturing a laminated iron core from a thin sheet, the method includes coining the thin sheet from above to form a thinned bridge portion on an outer peripheral portion of an iron core piece, blanking the iron core piece downwardly from the thin sheet using a set of an outer-shape blanking punch and a die after forming the bridge portion, wherein the outer-shape blanking punch includes a projection portion fitted into the bridge portion when blanking, and laminating the iron core piece on another iron core piece to manufacture the laminated iron core.

Abstract: In a method for manufacturing a laminated iron core from a thin sheet, the method includes coining the thin sheet from below to form a thinned bridge portion on an outer peripheral portion of an iron core piece, blanking the iron core piece from the thin sheet from above or below after forming the bridge portion, and laminating the iron core piece on another iron core piece to manufacture the laminated iron core.

Abstract: A dual-rotor motor provided with a stator having a stator core including a yoke, a plurality of teeth and a coil wound around the stator core, an inner rotor and an outer rotor, wherein the stator core includes an annular yoke component forming the yoke, and a plurality of tooth components forming the teeth. The stator core is made by fitting the tooth components individually into the annular yoke component in a manner that one ends of the tooth components protrude from the inner peripheral side of the annular yoke component and the other ends protrude from the outer peripheral side of the annular yoke component.

Abstract: A flux-controlled variable transformer can control voltage at a high speed without using any voltage adjusting tap. The transformer has a first and second magnetic circuits. The first magnetic circuit is composed of a first and second U-cut cores (13 and 11) which contact at their cut ends with each other in the state either of the two cores has been turned by 90.degree. in a twisting direction relative to the other. The primary winding (14) is wound in common around the second magnetic circuit and the first U-cut core (13) of the first magnetic circuit, the secondary winding (17) is wound around the second magnetic circuit and a control winding (12) is wound on the second U-cut core (11) of the first magnetic circuit. The magnetic flux linking the primary and secondary windings (14 and 17) can be controlled by change of the magnetic resistance in the first magnetic circuit with the primary winding (14) by changing a value of exciting current flowing in the control winding (12).

Abstract: This invention relates to a PWM power converter for switching a plurality of bridge-connected semiconductor switching elements based on PWM signals. As the semiconductor switching elements, elements with a low ON voltage and small conduction loss, and elements with a small switching loss and capable of high-speed switching are combined to improve power conversion efficiency.

Abstract: The present invention provides an optically controlled power converting apparatus using light trigger/light quench electrostatic induction thyristors, as switching elements, which can execute the switching operations at a high speed being when they are supplied with light trigger pulses and light quench pulses. By supplying the light trigger pulses and light quench pulses at the timings corresponding to the pulse width modulation, the light trigger/light quench electrostatic induction thyristors can perform predetermined power converting operations.