Abstract: An electric motor with a low cogging torque comprises a stator and a rotor. The stator comprises a plurality of stator teeth and a plurality of stator slots, wherein a number of the plurality of stator teeth is equal to a number of the plurality of stator slots, and the number of the plurality of stator slots is S. The rotor is disposed inside the stator, wherein the rotor comprises a plurality of magnetic poles, and a number of the plurality of magnetic poles is P, a ratio S/P of the number of the plurality of stator slots to the number of the plurality of magnetic poles is 7.5N, where the N is a positive integer.

Abstract: A rotor of an electric motor including a rotor core, two conductive end plates, a plurality of conductors and a casting metal is provided. The rotor core has a central hole and a plurality of slots surrounding the central hole at a predetermined interval. The two conductive end plates, disposed at two ends of the rotor core, have a plurality of fixing structures, respectively. A plurality of cavities is disposed between two neighboring fixing structures and the shape and the positions of the cavities correspond to that of the slots. The conductors are shaped as long bars and penetrate the slots. Two ends of the conductors are fixed by the fixing structures. The casting metal is injected into the cavities and the slots, and further covers the peripheral of the conductors and the fixing structures, two ends of the rotor core and outside of the two conductive end plates.

Abstract: A power collection device includes a carrier and a connection portion integrated with or attached to the carrier. The connection portion has a via for a wire to pass therethrough, a first side being in contact and connection with the carrier, a second side opposite to the first side, and a third side connected with the first and second sides. The via is in a shape of a circle, rectangle, square, rhombus, triangle with one side being close to the second side, or triangle with one angle being close to the second side. The via has a maximum length in a direction parallel to the first side being ¼ to ¾ times a length of the first side, and a maximum length in a direction perpendicular to the first side being ¼ to ¾ times a length from the first side to the second side.

Abstract: A rotor of an electric motor including a rotor core, two conductive end plates, a plurality of conductors and a casting metal is provided. The rotor core has a central hole and a plurality of slots surrounding the central hole at a predetermined interval. The two conductive end plates, disposed at two ends of the rotor core, have a plurality of fixing structures, respectively. A plurality of cavities is disposed between two neighboring fixing structures and the shape and the positions of the cavities correspond to that of the slots. The conductors are shaped as long bars and penetrate the slots. Two ends of the conductors are fixed by the fixing structures. The casting metal is injected into the cavities and the slots, and further covers the peripheral of the conductors and the fixing structures, two ends of the rotor core and outside of the two conductive end plates.

Abstract: A power collection device includes a carrier and a connection portion integrated with or attached to the carrier. The connection portion has a via for a wire to pass therethrough, a first side being in contact and connection with the carrier, a second side opposite to the first side, and a third side connected with the first and second sides. The via is in a shape of a circle, rectangle, square, rhombus, triangle with one side being close to the second side, or triangle with one angle being close to the second side. The via has a maximum length in a direction parallel to the first side being ¼ to ¾ times a length of the first side, and a maximum length in a direction perpendicular to the first side being ¼ to ¾ times a length from the first side to the second side.

Abstract: A power collection device for an electric machine is provided, which includes: a carrier having a first surface, and a connecting member protruding outward from the first surface of the carrier and having at least a first groove. The first groove facilitates to reduce stresses experienced by the connecting member and allows applied stresses to change the configuration of the connection portion so as to increase the contact area between the connecting member and an object held in the connecting member. As such, the object is firmly secured in the connecting member and the processing convenience is increased.