Abstract: A testing system includes an AC signal generator configured to selectively generate a sinusoidal signal including a plurality of cycles. A dielectric strength and partial discharge tester sequentially performs dielectric strength and partial discharge testing of a stator of an electric machine using the sinusoidal signal. Another testing system includes an impulse signal generator configured to selectively generate an impulse signal including a plurality of cycles. A surge and partial discharge tester for sequentially performing surge and partial discharge testing of a stator of an electric machine using the impulse signal.

Abstract: A method of installing a stator and a motor housing includes inserting a stator into a motor housing, the motor housing having a shaft bore and a plurality first bolt holes end of the state are having a bore opening and a plurality of second bolt holes. A centering fixture is inserted into the shaft bore of the housing and into the bore opening, the centering fixture includes a first centering device received into the shaft bore and a second centering device received into the bore opening of the stator. A locating plate is secured to the motor housing and engaged with the centering fixture. The first centering devices actuated for centering the centering fixture relative to the shaft and the second centering device is actuated for centering the state are relative to the shaft board. The plurality of bolts are tightened to secure the stator to the motor housing.

Abstract: An axial flux electric motor includes a housing including an inner surface and a stator fixedly mounted in the housing. The stator includes a plurality of stator segments each supporting a winding, an inner support member defining a central passage, and an outer annular member constraining the plurality of stator segments. The outer annular member includes an outer surface portion abutting the inner surface of the housing. A thermal connection system is disposed between the outer surface portion of the outer annular member and the inner surface. The thermal connection system transfers heat from the stator into the housing.

Abstract: A system for inspecting a stator stack includes a rotary table, an imaging device configured to take a plurality of images of a portion of the stator stack including a stator slot, an illuminator configured to apply illumination through the stator slot, and an alignment and monitoring system configured to monitor and orient the stator slot relative to the imaging axis. The alignment and monitoring system includes a tilting system configured to move the stator slot between a plurality of orientations relative to an imaging axis, the imaging device configured to take a respective image at each of the plurality of orientations, a controller configured to control the tilting system based on one or more measurements of each image, and a processor configured to analyze each image and select an orientation of the stator slot as an optimal orientation for inspection of the stator slot.

Abstract: A method of inspecting a stator stack includes disposing the stator stack on a support surface of an inspection system, and performing a depth measurement of a stator slot. The depth measurement includes rotating the stator slot along a first direction to a plurality of first orientations, taking a first image at each of the first orientations, and measuring a depth based on at least one of the first images. The method includes performing a width measurement of the stator slot, which includes rotating the stator slot along a second direction to a plurality of second orientations, taking a second image at each of the second orientations, and measuring a width based on at least one of the second images. The method further includes inspecting edges of the stator slot in the at least one of the first images to detect a potential deviation.

Abstract: An interlocking tool for a for forming stator end turns includes a first member including a first base having a first surface. A first ring extends from the first surface and a second ring extends from the first surface radially outwardly of the first ring. The second ring is spaced from the first ring by a first gap. A second member includes a second base having a first surface portion. A first ring element extends from the first surface portion and a second ring element extends from the first surface portion radially inwardly of the first ring element. The second ring element is spaced from the first ring element by a second gap. The second ring is positioned in the second gap, and the second ring element is positioned in the first gap. The first member is rotatable relative to the second member.

Abstract: Methods and systems for detecting partial discharge in a stator for an electric motor are provided. An exemplary method includes applying a high voltage AC sinewave input signal to the stator and energizing at least one winding therein. The method includes sensing a first resulting load signal occurring in the stator with a first device and filtering the first resulting load signal to form a first high frequency signal indicating any partial discharge (PD) voltage occurring in the stator. The method also includes sensing a second resulting load signal occurring in the stator with a second device and filtering the second resulting load signal to form a second high frequency signal indicating any partial discharge voltage occurring in the stator. Further, the method includes processing the first and second high frequency signals to form a processed signal indicating whether partial discharge occurred.

Abstract: Methods and systems for detecting partial discharge in a stator for an electric motor are provided. An exemplary method includes applying a high voltage AC sinewave input signal to the stator and energizing at least one winding therein. The method includes sensing a first resulting load signal occurring in the stator with a first device and filtering the first resulting load signal to form a first high frequency signal indicating any partial discharge (PD) voltage occurring in the stator. The method also includes sensing a second resulting load signal occurring in the stator with a second device and filtering the second resulting load signal to form a second high frequency signal indicating any partial discharge voltage occurring in the stator. Further, the method includes processing the first and second high frequency signals to form a processed signal indicating whether partial discharge occurred.

Abstract: An induction motor includes a stator and a rotor. The stator is configured to generate a rotating magnetic field. The rotor is disposed inside the stator, separated from the stator by an air gap, and is configured to rotate around an axis in response to the rotating magnetic field. The rotor includes a rotor core, multiple end rings, and multiple collars. The end rings are attached at opposite ends of the rotor core. Each end ring has one of multiple regions disposed outside the air gap. Each region has an outer surface. The collars are attached in a prestressed condition around the outer surface of each region. The prestressed condition is configured to maintain a compressive stress in the end rings at a maximum-designed rotational speed of the rotor.

Abstract: Stator cores and methods for fabricating stator cores are provided. An exemplary stator core includes a stack of laminations. Each lamination in the stack of laminations comprises a yoke and a plurality of tooth segments fixed to the yoke.

Abstract: An electric machine may include a substantially annular stator stack having a plurality of laminations which include mounting ears. A fraction of the laminations may be oriented such that the mounting ears are angularly offset from the others. The stator may be secured to a housing at both mounting ear locations thus improving structural rigidity and enhancing performance.

Abstract: An induction motor includes a stator and a rotor. The stator is configured to generate a rotating magnetic field. The rotor is disposed inside the stator, separated from the stator by an air gap, and is configured to rotate around an axis in response to the rotating magnetic field. The rotor includes a rotor core, multiple end rings, and multiple collars. The end rings are attached at opposite ends of the rotor core. Each end ring has one of multiple regions disposed outside the air gap. Each region has an outer surface. The collars are attached in a prestressed condition around the outer surface of each region. The prestressed condition is configured to maintain a compressive stress in the end rings at a maximum-designed rotational speed of the rotor.

Abstract: Systems and methods are provided for fixturing hairpins for joining by welding. A fixture system includes an outer structural ring fixed relative to an inner structural ring and mates with the component around its hairpin type conductor ends. Dielectric rings are disposed between conductor pairs. Clamp rings are disposed on opposite sides of the dielectric rings. One clamp ring and one dielectric ring define an opening receiving one conductor pair. Another clamp ring and another dielectric ring define another receiving another conductor pair. The clamp rings are movable toward one another to align and crowd the conductor pairs between the clamp rings and the dielectric rings prior to welding.

Abstract: Stator cores and methods for fabricating stator cores are provided. An exemplary stator core includes a stack of laminations. Each lamination in the stack of laminations comprises a yoke and a plurality of tooth segments fixed to the yoke.

Abstract: An electric machine may include a substantially annular stator stack having a plurality of laminations which include mounting ears. A fraction of the laminations may be oriented such that the mounting ears are angularly offset from the others. The stator may be secured to a housing at both mounting ear locations thus improving structural rigidity and enhancing performance.

Abstract: A partial discharge calibration standard apparatus may include a first and second rigid members defining respective first and second facing surfaces. An electrically insulating material may be disposed between the facing surfaces. The apparatus may further include a pressure member maintaining the rigid members together, thereby fixing the first and second facing surfaces in a substantially parallel spaced relation across the insulating material such that a partial discharge threshold magnitude for an electrical potential difference between the first and second facing surfaces is determined.

Abstract: A modular stator includes a first stator module and a second stator module. The first stator module includes a plurality of first coil end regions and a plurality of first junctions. The second stator module includes a plurality of second coil end regions and a plurality of second junctions. The first stator module and the second stator module are joined at the plurality of first junctions and the plurality of second junctions.

Abstract: Apparatus and methods are provided for manufacturing a rotor. The rotor has a core with an open center, conductive bars extending across the core and conductive end rings at ends of the core. A mandrel has a body that extends through the open center and a head that extends over and engage the first end of the core around the open center. A central cap couples with the body, extends over and engages the second end of the core around the open center. An end cap covers the central cap and engages the core around the open center. The end cap defines at least part of a cavity around the conductive bars for receiving molten metal.

Abstract: A method for manufacturing a stator includes the steps of: (1) providing a stator core module having a first stator fixture disposed on a first side of the stator core module, the first stator fixture is configured to support a first set of stator core junction portions in a fixed position; (2) providing a first crown module having a set of first crown junction portions and a first crown fixture to support the first set of first crown junction portions; (3) aligning the first stator fixture with the first crown fixture so that the first set of stator core junction portions are aligned with the first crown junction portions; and (4) joining the first set of stator core junction portions with the first crown junction portions.

Abstract: A method for manufacturing an induction rotor includes placing a lamination stack into a fixture in which the first end of the lamination stack is rotated in an opposite rotational direction from the second end of the lamination stack to skew the conduction bars to an angle ?. Vertical members are fixed to an outer perimeter of each of the plurality of laminates of the lamination stack. Hoop members are fixed to each of the plurality of vertical members and an outer edge of each of the plurality of conduction bars. A conduction ring is fixed on each of the ends of the lamination stack. An outer perimeter of the lamination stack is machined to remove the plurality of vertical members and the plurality of hoop members from the lamination stack.