Abstract: A method of servicing, or repairing a crack in, a dovetail portion of a dynamoelectric machine's rotor coil slot wall. The coil slot wall includes a radial entry surface connected to an inwardly tapered surface. The inwardly tapered surface is connected to an intermediate radial surface. A machining step machines a first groove in the radial entry surface and inwardly tapered surface. The first groove extends linearly to the intermediate radial surface. The first groove is configured so that a smooth and linear surface is created along a length of the first groove. A second machining step machines a second groove in the intermediate radial surface in an orientation substantially perpendicular to the first groove. A portion of the second groove contacts a portion of the first groove. At least one of the first groove and the second groove are configured to remove damaged material from the coil slot wall.

Abstract: A method of servicing, or repairing a crack in, a dovetail portion of a dynamoelectric machine's rotor coil slot wall. The coil slot wall includes a radial entry surface connected to an inwardly tapered surface. The inwardly tapered surface is connected to an intermediate radial surface. A machining step machines a first groove in the radial entry surface and inwardly tapered surface. The first groove extends linearly to the intermediate radial surface. The first groove is configured so that a smooth and linear surface is created along a length of the first groove. A second machining step machines a second groove in the intermediate radial surface in an orientation substantially perpendicular to the first groove. A portion of the second groove contacts a portion of the first groove. At least one of the first groove and the second groove are configured to remove damaged material from the coil slot wall.

Abstract: A rotor train torsional mode frequency tuning apparatus is provided and includes a rotor train and a coupling element. The rotor train includes first and second shafts and a coupling operably disposed between the first and second shafts and has a torsional mode frequency. The coupling element is disposed at the coupling and is configured to adjust the torsional mode frequency of the rotor train by a change in at least one of inertia and/or torsional stiffness in the rotor train.

Abstract: Systems and devices for thermodynamically regulating portions of a dynamoelectric machine are disclosed. In one embodiment, a fan assembly element includes: an axially inner shroud segment configured to form a portion of an annular assembly about a rotor of a dynamoelectric machine, wherein the axially inner shroud segment includes a rotor hub interface configured to physically connect to a complementary portion of a rotor hub; a set of fan blades physically connected to and extending axially from a face of the axially inner shroud segment; and an axially outer shroud segment physically connected to the set of fan blades.

Abstract: Systems and devices for thermodynamically regulating portions of a dynamoelectric machine are disclosed. In one embodiment, a fan assembly element includes: an axially inner shroud segment configured to form a portion of an annular assembly about a rotor of a dynamoelectric machine, wherein the axially inner shroud segment includes a rotor hub interface configured to physically connect to a complementary portion of a rotor hub; a set of fan blades physically connected to and extending axially from a face of the axially inner shroud segment; and an axially outer shroud segment physically connected to the set of fan blades.

Abstract: A solution is provided for tuning the frequency of a torsional mode of interest of a rotating body (such as a generator rotor torsional mode) by adding a detuner to act as an undamped torsional vibration absorber. The detuner may be coupled to an overhung shaft extending from the rotating body. The detuner may be modular, therefore weight can be added or subtracted easily from the detuner in order to adjust the stiffness and/or inertia of the overhung shaft. This change in stiffness and/or inertia yields a torsional frequency of oscillation in the overhung shaft substantially similar to the natural frequency of the torsional mode of interest of the rotating body, therefore forcing the frequency of the torsional mode of interest of the rotating body above or below its torsional natural frequency.

Abstract: Re-machining a generator rotor tooth dovetail results in a transition zone at an end of the partial re-machined cut, between a newly cut load surface and an original load surface of the rotor tooth. The transition zone is susceptible to stresses that may adversely affect the fatigue strength of the rotor tooth. These stresses can be reduced by the steps of (a) forming at least one axial undercut stress relief groove across the transition zone between the newly cut load surface and the original load surface, (b) cutting and shaping a wedge that will fit in the transition zone, and (c) securing the wedge across the transition zone.

Abstract: A solution is provided for tuning the frequency of a torsional mode of interest of a rotating body (such as a generator rotor torsional mode) by adding a detuner to act as an undamped torsional vibration absorber. The detuner may be coupled to an overhung shaft extending from the rotating body. The detuner may be modular, therefore weight can be added or subtracted easily from the detuner in order to adjust the stiffness and/or inertia of the overhung shaft. This change in stiffness and/or inertia yields a torsional frequency of oscillation in the overhung shaft substantially similar to the natural frequency of the torsional mode of interest of the rotating body, therefore forcing the frequency of the torsional mode of interest of the rotating body above or below its torsional natural frequency.

Abstract: Re-machining a generator rotor tooth dovetail results in a transition zone at an end of the partial re-machined cut, between a newly cut load surface and an original load surface of the rotor tooth. The transition zone is susceptible to stresses that may adversely affect the fatigue strength of the rotor tooth. These stresses can be reduced by the steps of (a) forming at least one axial undercut stress relief groove across the transition zone between the newly cut load surface and the original load surface, (b) cutting and shaping a wedge that will fit in the transition zone, and (c) securing the wedge across the transition zone.