Abstract: A stator includes a stator core having a plurality of slots in a circumferential direction about an axis and having an end surface in a direction of the axis, and a first coil and a second coil of different phases which are wound on the stator core in distributed winding. A winding factor is 1. Each of the first coil and the second coil has winding portions, the number of which corresponds to the number of poles. The winding portions include first and second winding portions adjacent to each other in the circumferential direction. The first and second winding portions are inserted into one slot of the plurality of slots and extend from the one slot to both sides in the circumferential direction on the end surface. The first and second coils are annularly disposed in different positions in a radial direction about the axis on the end surface.

Abstract: A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.

Abstract: A stator includes a stator core and a coil wound around the stator core. The coil includes at least one first winding and at least one second winding connected to the first winding in series. The stator satisfies (C1/S1)>(C2/S2), where S1 is a total cross-sectional area on a first side of a coil-end part of the coil, S2 is a total cross-sectional area on a second side of the coil-end part, C1 is a total cross-sectional area of the first winding on the first side, and C2 is a total cross-sectional area of the first winding on the second side.

Abstract: An electric motor includes a rotor and a stator. The stator includes a first stator core located on a first side in the axial direction, and a second stator core located on a second side. The minimum distance from a rotor core of the rotor to the first stator core in the radial direction is smaller than the minimum distance from the rotor core to the second stator core in the radial direction. Each tooth of the first stator core includes a tooth end portion. The tooth end portion includes a main body extending in the radial direction, and a first portion extending in the circumferential direction, and a second portion projecting from the first portion in the radial direction.

Abstract: A first coil including a first metal, and a second coil including a second metal having a lower electrical resistivity than the first metal are disposed in a slot of a stator core. The slot includes a slot opening, a curved slot bottom portion connecting to a yoke, and first and second side portions disposed between the slot opening and the slot bottom portion. A first straight line connects borders between the slot bottom portion and either of the side portions. A first region is surrounded by the first straight line and the slot bottom portion. A second region is located between the slot opening and the first straight line in the radial direction. Areas S1 and S2 of the first and second regions, and total cross-sectional areas A1 and A2 of the first coil in the first and second regions satisfy (A1/S1)>(A2/S2).

Abstract: An electric motor includes: a rotor including a first rotor core and a second rotor core; and a stator. A minimum distance from the first rotor core to the stator is shorter than a minimum distance from the second rotor core to the stator. A maximum radius of the first rotor core is longer than a maximum radius of the second rotor core. A shape of a first thin-wall part of the first rotor core and a shape of a second thin-wall part of the second rotor core are the same.

Abstract: A slot includes a coil housing portion having first and second side portions and a bottom portion. A first straight line connects first and second points which are boundaries between the bottom portion and the side portions. A slot opening has third and fourth points closest to the first and second side portions. A second straight line connects the first and third points. A third straight line connects the second and fourth points. A first region is surrounded by the first straight line and the bottom portion. A second region is surrounded by the second straight line and the first side portion, and is surrounded by the third straight line and the second side portion. A third region is surrounded by the three straight lines. Areas A1, A2 and A3 of the three regions and total cross-sectional areas S1, S2, S3 of coils therein satisfy (S1/A1)>(S2/A2)>(S3/A3).

Abstract: A rotor includes a rotor core, a permanent magnet, a first part, a second part, and a third part. The third part is formed integrally with the first part and the second part. The rotor core is longer than the permanent magnet in an axial direction.

Abstract: An electric motor includes a rotor including a first rotor end and a second rotor end, and a stator including a first stator end and a second stator end. The first rotor end is located apart from the first stator end toward the first side. The second rotor end is located apart from the second stator end toward the first side. The relationship between the distances D1 and D2 satisfies D1>D2?0, where D1 is a distance from a permanent magnet to a first end plate, and D2 is a distance from the permanent magnet to a second end plate. The thickness of each of a plurality of electrical steel sheets is not less than 0.1 mm and not more than 0.25 mm.

Abstract: A hot-water supply system heats up water by power generated by power generation means. The hot water supply system includes a compressor and a water heat-up unit. In the hot-water supply system, the compressor compresses refrigerant and circulates the refrigerant through a refrigerant circuit. The water heat-up unit heats up water by changing, in accordance with the generated power, a rotation rate of an electric motor for driving the compressor.

Abstract: A rotor includes a rotor core and a permanent magnet. The rotor core includes an outside slit provided between a permanent magnet insertion hole and an outer peripheral surface of the rotor core, and inside slits provided between a magnetic pole center part and the outside slit. A minimum distance from a first inside slit to the outer peripheral surface of the rotor core is longer than a minimum distance from any other inside slit except the first inside slit to the outer peripheral surface of the rotor core.

Abstract: A rotor core has first and second magnet insertion holes along an outer circumference, and first and second slits along an inner circumference. The first and second slits have first and second facing portions facing each other. The first facing portion has a first inner end and a first outer end. The second facing portion has a second inner end and a second outer end. An inter-slit portion is provided between the first and second facing portions and is defined by a first straight line connecting the first and second inner ends and a second straight line connecting the first and second outer ends. In a radial direction of the rotor core, a minimum distance D1 from the inner circumference to the slits, a minimum width W1 of the slits, and a length W2 of the inter-slit portion satisfy at least one of D1<W1 and D1<W2.

Abstract: A stator includes a stator core having a plurality of slots in a circumferential direction about an axis and having an end surface in a direction of the axis, and a first coil and a second coil of different phases which are wound on the stator core in distributed winding. A winding factor is 1. Each of the first coil and the second coil has winding portions, the number of which corresponds to the number of poles. The winding portions include first and second winding portions adjacent to each other in the circumferential direction. The first and second winding portions are inserted into one slot of the plurality of slots and extend from the one slot to both sides in the circumferential direction on the end surface. The first and second coils are annularly disposed in different positions in a radial direction about the axis on the end surface.

Abstract: A stator includes a stator core and a winding wound around the stator core in wave winding. The winding includes an assembly of a plurality of covered wires, and an outer cover film that surrounds and covers the assembly and contains thermosetting resin. Each of the covered wires includes a conductor and an insulating film surrounding and covering the conductor. Each of the covered wires has a wire width of 1.5 mm or less.

Abstract: An electric motor includes a rotor and a stator. The rotor includes a rotor core and a plurality of permanent magnets fixed to an outer surface of the rotor core. The stator includes a stator core including a tooth part and a winding wound around the stator core. The electric motor satisfies an expression of 1<t2/t1?8 where t1 is a minimum distance from a center of a front end surface of the tooth part to one permanent magnet of the plurality of permanent magnets and t2 is a distance from an end of the tooth part to the one permanent magnet.

Abstract: A sensor magnet includes: a first magnetic-pole part including a magnetic pole of first polarity; a second magnetic-pole part including a magnetic pole of second polarity; and an inter-pole part formed between the first magnetic-pole part and the second magnetic-pole part. A width of the inter-pole part is larger than both of a width of the first magnetic-pole part and a width of the second magnetic-pole part.

Abstract: An electric motor includes a rotor and a stator. The stator includes a first stator core located on a first side in the axial direction, and a second stator core located on a second side. The minimum distance from a rotor core of the rotor to the first stator core in the radial direction is smaller than the minimum distance from the rotor core to the second stator core in the radial direction. Each tooth of the first stator core includes a tooth end portion. The tooth end portion includes a main body extending in the radial direction, and a first portion extending in the circumferential direction, and a second portion projecting from the first portion in the radial direction.

Abstract: A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.

Abstract: A permanent-magnet synchronous motor includes: an annular stator core; a cylindrical rotor disposed inside the stator core, and having a first end face in an axial direction of the stator core and a second end face in the axial direction; a disk-shaped sensor magnet having a plurality of magnetic poles disposed circumferentially, and having a third end face and a fourth end face; and a magnetic sensor disposed so as to be opposed to the fourth end face in the axial direction, and detecting a rotating position of the sensor magnet. When a first thickness means the axial thickness at the center of each of the magnetic poles and a second thickness means the axial thickness of an inter-magnetic-pole portion between adjacent magnetic poles of the magnetic poles, the second thickness is greater than the first thickness.

Abstract: A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.