Generator stator frame construction isolates normal core generateddouble frequency vibration from the foundation and distributesairflow to provide uniform temperatures in the core.

Flexible Stator Core Mounting(Model series 2800 and larger)

For each complete revolution of the rotor,every portion of the stator is twicesubjected to the strong magnetic attractionof a rotor field pole. At 3,600 rpm thiscauses 120 vibrations per second,producing a characteristic low frequencyhum. To absorb this vibration, and tominimize audible low frequency hum, thestator core is flexibly mounted. The flexiblecore mounting design is based on the thincylinder principle, which recognizes thatcylinders can provide flexibility in the radialdirection and still support heavy loads ina tangential direction. The cylindricalmountings are sectioned to provide supportat each end of the stator and in the centerof the core. The core supports are fastenedto the ends of the cylinders with steelplates. Fame plates connect the oppositeend of each cylinder to the foot plate. Thepulsation of the core is absorbed by thecylinders rather than being transmitted tothe foundation.

Circular StudsLarge diameter circular studs are weldedto the machined stator bore to give addedsupport and act as keys for core laminationstacking. Steel wrapper plates enclose theframe and provide additional support.

2-Pole Turbine GeneratorsStator Construction

WARRANTY

Frame-TEWAC or Room AirCooledThe stator frame is designed to provideeither a totally enclosed water-air-cooled(TEWAC) or a room air cooled (RAC)housing for the generator. Air is recirculatedin the TEWAC machine through air towater heat exchangers. Air is circulated inthe RAC machine with intake air drawingin the ends and air discharged out the topcenter. The frame is fabricated from thicksteel plates with all weldments speciallycontrolled to assure integrity of structure.The cross section plates are cut on anumerically controlled machine to assureuniformity from section to section.

2-Pole Turbine GeneratorsStator Construction

Flexible Stator Core Mounting(Model series 2800 and larger)

For each complete revolution of the rotor, every portion of the stator is twice subjected to the strong magnetic attraction of a rotor field pole. At 3,600 rpm this causes 120 vibrations per second, producing a characteristic low frequency hum. To absorb this vibration, and to minimize audible low frequency hum, the stator core is flexibly mounted. The flexible core mounting design is based on the thin cylinder principle, which recognizes that cylinders can provide flexibility in the radial direction and still support heavy loads in a tangential direction. The cylindrical mountings are sectioned to provide support at each end of the stator and in the center of the core. The core supports are fastened to the ends of the cylinders with steel plates. Fame plates connect the opposite end of each cylinder to the foot plate. The pulsation of the core is absorbed by the cylinders rather than being transmitted to the foundation.

Circular StudsLarge diameter circular studs are welded to the machined stator bore to give added support and act as keys for core lamination stacking. Steel wrapper plates enclose the frame and provide additional support.

Frame-TEWAC or Room Air CooledThe stator frame is designed to provide either a totally enclosed water-air-cooled (TEWAC) or a room air cooled (RAC) housing for the generator. Air is recirculated in the TEWAC machine through air to water heat exchangers. Air is circulated in the RAC machine with intake air drawing in the ends and air discharged out the top center. The frame is fabricated from thick steel plates with all weldments specially controlled to assure integrity of structure. The cross section plates are cut on a numerically controlled machine to assure uniformity from section to section.

Generator stator frame construction isolates normal core generated double frequency vibration from the foundation and distributes airflow to provide uniform temperatures in the core.

Stator frame center fabrication.

Stator CoreThe stator core consists of high siliconelectrical steel laminations that are blankedand notched simultaneously for specialhigh quality core plated sheet steel. Afterthe punching operation, each lamination isprecision edge ground to remove burrs.The burr grinding process is controlled soaccurately that the burr is removed withoutdestroying the core plated insulation film.The lamination segments are stacked oncircular studs, which extend lengthwisewithin the stator frame. As the stator corelaminations are stacked, vent duct spacersare inserted at specific intervals to providecooling passages in the stator core foruniform cooling. Special care is taken toassure accurate slot alignment over thelength of the core.

Electric Machinery800 Central Avenue NEMinneapolis, Minnesota 55413United StatesTel: +1 612 378 8000Fax: +1 612 378 8051www.electricmachinery.com

© Electric Machinery 2011. Publication NA.10004.gb.11-09.01. Electric Machinery, the Electric Machinery logo and any version thereof are trademarks and service marks of Electric Machinery.The other names mentioned, registered or not, are the property of their respective companies.

WARRANTY

www.converteam.com

Converteam Electric Machinery800 Central Avenue NEMinneapolis, Minnesota 55413United StatesTel: +1 612 378 8000Fax: +1 612 378 8051

North America Headquarters:Converteam Inc.Pittsburgh, PennsylvaniaTel: +1 412 967 0765

France Tel: +33 1 77 31 20 00Germany Tel: +49 30 76 22 0UK Tel: +44 1788 563563Brazil Tel: +55 31 3330 5800China Tel: +86 21 6442 1666India Tel: +91 44 2440 0900Russia Tel: +7 495 225 1916

Stator CoreThe stator core consists of high silicon electrical steel laminations that are blanked and notched simultaneously for special high quality core plated sheet steel. After the punching operation, each lamination is precision edge ground to remove burrs. The burr grinding process is controlled so accurately that the burr is removed without destroying the core plated insulation film. The lamination segments are stacked on circular studs, which extend lengthwise within the stator frame. As the stator core laminations are stacked, vent duct spacers are inserted at specific intervals to provide cooling passages in the stator core for uniform cooling. Special care is taken to assure accurate slot alignment over the length of the core.

Accurate clamping pressure is applied to both ends of the stator core through non-magnetic pressure plates. These plates and the tooth support fingers have a special concave design. When properly pressurized, they will exert a uniform pressure on the face of the stator core teeth as well as the back of the stator core.

End StacksThe end sections of the stator core are stepped back from the air gap to minimize fringing flux and to reduce end iron heating when the machine is operated outside of the normal power factor range.

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Installation of stator core clamping plates on lamination stack.

Stacked stator frame ready for winding of stator coils.

Accurate clamping pressure is applied toboth ends of the stator core throughnon-magnetic pressure plates. These platesand the tooth support fingers have aspecial concave design. When properlypressurized, they will exert a uniformpressure on the face of the stator coreteeth as well as the back of the stator core.

End StacksThe end sections of the stator core arestepped back from the air gap to minimizefringing flux and to reduce end ironheating when the machine is operatedoutside of the normal power factor range.