There is provided a dynamo-electric machine that can provide excellent insulating properties by downsizing coil ends. A dynamo-electric machine includes a stator and a rotator. The stator has a stator iron core formed with a plurality of slots arranged in a circumferential direction, and a stator coil inserted into the slots of the stator iron core. The rotator is rotatably disposed on the stator iron core with a predetermined gap. The stator coil is provided with an insulating film. The stator coil includes a main coil and a lead wire with an alternating current terminal. The main coil has a plurality of segment coils connected to one another. The segment coil is a conductor in a rectangular cross section formed in advance in a nearly U-shape. The lead wire is led from the slot. The tip end of the segment coil is formed in a trapezoid cross section.

There is provided a dynamo-electric machine that can provide excellent insulating properties by downsizing coil ends. A dynamo-electric machine includes a stator and a rotator. The stator has a stator iron core formed with a plurality of slots arranged in a circumferential direction, and a stator coil inserted into the slots of the stator iron core. The rotator is rotatably disposed on the stator iron core with a predetermined gap. The stator coil is provided with an insulating film. The stator coil includes a main coil and a lead wire with an alternating current terminal. The main coil has a plurality of segment coils connected to one another. The segment coil is a conductor in a rectangular cross section formed in advance in a nearly U-shape. The lead wire is led from the slot. The tip end of the segment coil is formed in a trapezoid cross section.

A coil is wound via an electrically insulating member within a slot of a stator core of an electromagnetic motor which is formed of a stator and a rotor. Groove portions are formed to oppose one another in respective opposing portions of a slot opening portion side of the electrically insulating member. An electrically insulating sheet is disposed by being inserted into the pair of groove portions.

Disclosed herein is a common mode filter that includes a winding core part including a first winding area positioned at one end side in an axial direction, a second winding area positioned at other end side in the axial direction, and a third winding area positioned between the first and second winding areas; and first and second wires wound in a same direction around the winding core part. The first wire is aligned and wound in the first and second winding areas, and the second wire is wound on the first wire in the first and second winding areas. The first and second wires cross each other in the third winding area and are separated at least partially in the third winding area.

Disclosed herein is a common mode filter that includes a winding core part including a first winding area positioned at one end side in an axial direction, a second winding area positioned at other end side in the axial direction, and a third winding area positioned between the first and second winding areas; and first and second wires wound in a same direction around the winding core part. The first wire is aligned and wound in the first and second winding areas, and the second wire is wound on the first wire in the first and second winding areas. The first and second wires cross each other in the third winding area and are separated at least partially in the third winding area.

Disclosed herein is a common mode filter that includes a winding core part including first to third winding areas and first and second wires wound in a same direction around the winding core part and crossing each other in the third winding area. The first wire is aligned and wound in the first and second winding areas, and the second wire is aligned and wound on the first wire in the first and second winding areas, whereby a plurality of winding blocks are formed. The winding blocks include a first winding block positioned in the first winding area and second and third winding blocks positioned in the second winding area. The second wire constituting the second winding block and the second wire constituting the third winding block are separated from each other.

Disclosed herein is a common mode filter that includes a winding core part including first to third winding areas and first and second wires wound in a same direction around the winding core part and crossing each other in the third winding area. The first wire is aligned and wound in the first and second winding areas, and the second wire is aligned and wound on the first wire in the first and second winding areas, whereby a plurality of winding blocks are formed. The winding blocks include a first winding block positioned in the first winding area and second and third winding blocks positioned in the second winding area. The second wire constituting the second winding block and the second wire constituting the third winding block are separated from each other.

A phase-to-phase insulation partial discharge inspection apparatus includes: an impulse power supply (1) configured to apply an impulse voltage having a voltage rise time period tr which satisfies an expression tr>(.sub.coil.Math.V.sub.max)/(PDIV) to a rotary electric machine (2); a measurement section (12) configured to measure partial discharge which occurs when the impulse voltage is applied to the rotary electric machine (2); and a decision section (15) configured to determine that, when partial discharge is not measured by the measurement section (12), a phase-to-phase insulation performance is acceptable. In the expression, .sub.coil is a surge propagation time period of one coil of a rotary electric machine winding, PDIV a partial discharge inception voltage between winding turns, and V.sub.max a peak of a partial discharge testing voltage for the phase-to-phase insulation.

A phase-to-phase insulation partial discharge inspection apparatus includes: an impulse power supply (1) configured to apply an impulse voltage having a voltage rise time period tr which satisfies an expression tr>(.sub.coil.Math.V.sub.max)/(PDIV) to a rotary electric machine (2); a measurement section (12) configured to measure partial discharge which occurs when the impulse voltage is applied to the rotary electric machine (2); and a decision section (15) configured to determine that, when partial discharge is not measured by the measurement section (12), a phase-to-phase insulation performance is acceptable. In the expression, .sub.coil is a surge propagation time period of one coil of a rotary electric machine winding, PDIV a partial discharge inception voltage between winding turns, and V.sub.max a peak of a partial discharge testing voltage for the phase-to-phase insulation.

A spindle motor includes a stationary portion, a rotating portion arranged to rotate about a central axis extending in a vertical direction, and a bearing portion arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion. The stationary portion includes a stator unit including a plurality of coils arranged in an annular shape with the central axis as a center; a base portion arranged below the stator unit; and a housing arranged to define an interior space in which the rotating portion, the bearing portion, and the stator unit are accommodated. The base portion includes a through hole arranged to pass through the base portion in an axial direction to join an outside of the housing and the interior space to each other; a sheet arranged to cover an upper opening of the through hole to close the through hole; a filler arranged to cover a lower opening of the through hole; and a vent passage defined in at least one of the base portion and the sheet to join the through hole and the interior space to each other. Thus, the filler can be easily put into the through hole.