General Electric Company

Vincent G Terry

Richard J Keck

Edmund E Kazmierczak

Dennis R Ulery

James R Pedersen

Duncan N Walker

Brian E Gott

Robert Gerald Hamilton

John F Lawyer

Disclosed is a rotor body for an electric machine having slots for windings and slot keys with wedges for retaining the windings in the slots. The slot keys contain elongated spring strips underlying an amortisseur, in turn, underlying the wedges in the slot keys. The spring strips bias the amortisseur and wedges radially outwardly. Thus, the wedges lie in sufficient, low-resistance, efficient electrical contact with the rotor body at start-up and during low rotor speeds to prevent arcing and localized heating along the interfaces of the rotor parts otherwise resultant from induced surface currents at start-up and low rotor speeds. At the rotor ends, the spring strips bias the amortisseur ends radially outwardly into efficient electrical contact with retaining rings at opposite ends of the rotor body. A tool is also provided having a main arm, a pair of pivotally mounted dogs for engagement in the slot key and straddling the external surface of the slot key, respectively, whereby the tool may be fixed in axial position along the slot key by pressure on the main arm. A second pivotal arm carries a wedge-engaging head whereby the lever is fixed in the slot and the second arm drives the wedge longitudinally into axial position in the slot key.

Apparatus affording efficient electrical contact between rotor surface

A tool for applying slot wedges having a main arm, a pair of pivotally mounted dogs for engagement in the slot key and straddling the external surface of the slot key, respectively, whereby the tool may be fixed in axial position along the slot key by pressure on the main arm. A second pivotal arm carries a wedge-engaging head whereby the lever is fixed in the slot and the second arm drives the wedge longitudinally into axial position in the slot key.

Tool for applying slot wedges

A brushless exciter for a dynamoelectric machine includes a rectifier assembly disposed in a cylindrical cavity on an axis of the shaft of the dynamoelectric machine. The rectifier assembly is made up of a stack of generally circular heat-sink discs with a cylindrical diode sandwiched on the axis between adjacent pairs of the heat-sink discs. A predetermined value of contact force is applied to the diodes through the stack of heat-sink discs using a plurality of tensioning bolts passing through the stack and tensioned using Belleville springs. All electrical connections to the diodes are made through the heat-sink discs using conductor bars which pass in aligned slots in the edges of the heat-sink discs, each making contact with only a desired single one of the heat-sink discs. A plurality of air flow openings in the heat-sink discs both permit the passage of air therethrough and also flow cooling air onto the body of the diodes. The flow of cooling air is enhanced by providing exit openings for the cooling air which are located at greater diameters than the diameter of the cylindrical cavity containing the rectifier assembly. This permits centrifugal force to add to the air flow.

Brushless exciter with zero-gravity rectifier assembly

Keybars for affixing stator core laminations to annular web plates of a stator frame include a cylindrical portion and a dovetail portion. The cylindrical portion is closely fitted within accurately bored axially aligned circular holes in the annular web plates. During preliminary assembly, the cylindrical portions of the keybars are inserted into the aligned bored cylindrical holes in the annular web plates with the dovetail portions facing radially inward. Due to the accuracy with which the bored cylindrical holes are positioned, chordal positioning of the keybars prior to welding is achieved with a jig positionable between adjacent keybars. During welding, the keybars are pulled radially inward to place all clearances between the circular portions and the bored cylindrical holes radially outward of the cylindrical portion.

Dynamoelectric machine stator using cylindrical keybars

A coupling between a prime mover and a dynamoelectric machine should include electrical insulation between the connected shafts so as to preclude the transmission of eddy currents between the dynamoelectric machine to the prime mover shaft. This insulation may be provided at the radial interface between coupling members. However, it has been found that the torque carrying capability of a coupling may be enhanced by providing a circumferential electrical insulation between radially inner and outer hubs which comprise the coupling member on the dynamoelectric machine side of the coupling.

Insulated coupling

A coupling member is shrink fitted onto the end of a dynamoelectric machine shaft and keyed thereto with a plurality of hollow keys of circular cross section which distort if excessive torque is applied to the coupling, reducing the risk of coupling failure. This coupling exhibits the properties of high strength and low weight which eliminates lateral shaft resonance at operating speeds.

Shaft end coupling for a dynamoelectric machine

A dynamoelectric machine load package has an acoustically isolated enclosure for reducing the amount of structure-borne and air-borne vibration and noise reaching the surrounding environment. Bearing pedestals for supporting a rotating shaft of a rotating field winding of a dynamoelectric machine and a reduction gear for driving the rotating shaft are firmly mounted on a load package base which is firmly attached to a foundation. The enclosure and a stationary armature of the dynamoelectric machine are independently resiliently mounted on the load package base. The enclosure is free to vibrate independently of the load package so that vibrations are not directly transmitted from the load package to the enclosure and are not directly transmitted from the enclosure to the load package base. Acoustic damping material is applied to interior walls of the enclosure.

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Beverly, MA, United States of America

Vincent G Terry