An electric motor and a method of making the electric motor is disclosed herein. The motor comprises a stator and a rotor being arranged coaxially, with said rotor provided internally of said stator. The stator having one or more stator teeth extending radially inwardly towards said rotor. The rotor has a plurality of magnets forming an outer rotor surface. A first face of the or each stator tooth faces the outer rotor surface. An electrically-conductive non-magnetic damper bar is partially embedded in the or each stator tooth, the or each damper bar having an outer damper bar surface. A groove is formed in the first face of the or each stator tooth to at least partially expose the outer damper bar surface. The groove can improve flux linkage between the rotor and the damper bars and thus improve the damping of the electric motor.

A rotating electric machine having a fraction slot configuration in which the number of slots per pole per phase is not an integer includes: a stator that includes a stator core provided with a plurality of slots, and a stator winding having a plurality of coil sides accommodated in the plurality of slots and a plurality of coil ends connecting the same side end parts of the plurality of coil sides to each other; and a movable element that is supported to be movable with respect to the stator, and includes a movable element core, and a plurality of movable element magnetic poles provided in the movable element core. The stator winding includes a plurality of basic coils in which the magnitude of magnetomotive force generated by the plurality of coil sides forming the one-phase band is uniform in each of the plurality of movable element magnetic poles.

A rotating electric machine having a fraction slot configuration in which the number of slots per pole per phase is not an integer includes: a stator that includes a stator core provided with a plurality of slots, and a stator winding having a plurality of coil sides accommodated in the plurality of slots and a plurality of coil ends connecting the same side end parts of the plurality of coil sides to each other; and a movable element that is supported to be movable with respect to the stator, and includes a movable element core, and a plurality of movable element magnetic poles provided in the movable element core. The stator winding includes a plurality of basic coils in which the magnitude of magnetomotive force generated by the plurality of coil sides forming the one-phase band is uniform in each of the plurality of movable element magnetic poles.

Provided is a motor system adapted for modern society, which does not use a rare-earth magnet, improves a torque weight ratio by approximately one digit in comparison with the conventional motor, and has transfer efficiency of 90% between electric energy and rotational energy. A stator (1) has a dual-ring tooth-groove iron core, which has magnetic pole surface on both side surfaces and receives coils of basically two-phase structure divided to be multiplexed, with divided coils being interconnected. A rotor (2) is formed to be capable of rotating while holding eight sets of attraction poles having magnetic pole surfaces on both ends, with each set of attraction poles forming four air-gap-facing surfaces by positioning the dual-ring tooth-groove iron core between the attraction poles so that both side surfaces of the dual-ring tooth-groove iron core face the attraction poles via an air gap (6). Magnetic energy accompanying coil switching can be reduced to one part per dozens through the dual effect of reduction owing to coil division and dispersion owing to interconnection. The torque weight ratio can be improved approximately by one digit through synergistic effect of torque increase owing to integration of magnetomotive forces by interconnection, torque increase owing to composite structure of the attraction poles, and weight reduction of the iron core.

Provided is a motor system adapted for modern society, which does not use a rare-earth magnet, improves a torque weight ratio by approximately one digit in comparison with the conventional motor, and has transfer efficiency of 90% between electric energy and rotational energy. A stator (1) has a dual-ring tooth-groove iron core, which has magnetic pole surface on both side surfaces and receives coils of basically two-phase structure divided to be multiplexed, with divided coils being interconnected. A rotor (2) is formed to be capable of rotating while holding eight sets of attraction poles having magnetic pole surfaces on both ends, with each set of attraction poles forming four air-gap-facing surfaces by positioning the dual-ring tooth-groove iron core between the attraction poles so that both side surfaces of the dual-ring tooth-groove iron core face the attraction poles via an air gap (6). Magnetic energy accompanying coil switching can be reduced to one part per dozens through the dual effect of reduction owing to coil division and dispersion owing to interconnection. The torque weight ratio can be improved approximately by one digit through synergistic effect of torque increase owing to integration of magnetomotive forces by interconnection, torque increase owing to composite structure of the attraction poles, and weight reduction of the iron core.

The present invention is an amortisseur upgrade which augments features of the traditional amortisseur. By introducing four features, the aggressive differential thermal growth, due to an excessive power onrush, beyond the intended design duty, during generator startup, is managed. The upgrades include: shallow clearance counter-bores in the generator end cap, flexible shorting plates, hollow damper rod ends, and spacers which are integrated into the shorting plates. These features, when implemented into the traditional amortisseur, manage the aggressive thermal growth response of the amortisseur assembly.

The present invention is an amortisseur upgrade which augments features of the traditional amortisseur. By introducing four features, the aggressive differential thermal growth, due to an excessive power onrush, beyond the intended design duty, during generator startup, is managed. The upgrades include: shallow clearance counter-bores in the generator end cap, flexible shorting plates, hollow damper rod ends, and spacers which are integrated into the shorting plates. These features, when implemented into the traditional amortisseur, manage the aggressive thermal growth response of the amortisseur assembly.

A method of manufacturing a rotor of an electric motor or an electric generator includes positioning a plurality of amortisseur bars and using additive manufacturing to place electrically conductive material. More specifically, positioning the amortisseur bars may include circumferentially positioning the bars around a rotor stack and using additive manufacturing to place electrically conductive material may include forming a non-solid pattern of electrically conductive material, such as a pattern of electrically conductive traces, across opposite axial ends of the rotor stack to electrically interconnect an amortisseur circuit.

A method of manufacturing a rotor of an electric motor or an electric generator includes positioning a plurality of amortisseur bars and using additive manufacturing to place electrically conductive material. More specifically, positioning the amortisseur bars may include circumferentially positioning the bars around a rotor stack and using additive manufacturing to place electrically conductive material may include forming a non-solid pattern of electrically conductive material, such as a pattern of electrically conductive traces, across opposite axial ends of the rotor stack to electrically interconnect an amortisseur circuit.

A stator of a polyphase motor in which in-phase coils are connected in parallel includes an annular core back, teeth extending radially from the core back and arranged circumferentially, a slot between two adjacent teeth, conducting wires respectively wound around the teeth to define the coils, and first and second connectors to which ends of each of the in-phase coils are connected, respectively. The conducting wire includes one or two jumper wires between each coil and the first connector or the second connector, and at least one jumper wire extends in an identical circumferential direction from the first connector toward the second connector with respect to all the in-phase coils.