Kabushiki Kaisha Toshiba

Ryoji Nagano

Kazuhiro Saito

Koji Matsuyama

Yomei Yoshioka

Hiromichi Ito

Hiroaki Koinuma

Yasuo Kabata

Toshio Kitajima

Hideki Chiba

Kaname Hirai

A method for removing a crack in an electromechanical rotor, including: forming a plurality of slots on a periphery of a core portion of an electromechanical rotor along an axial direction thereof; inserting coils into the slots, respectively; forming a plurality of wedges for maintaining the coils in the slots, respectively; and forming a cut hole at at least a part of the core portion from an outer surface of the core portion toward the side of a center axis thereof so as to contain a crack along a circumferential direction thereof.

Method for removing a crack in an electromechanical rotor

A method for repairing a crack in an electromechanical rotor (), including forming a plurality of slots () on a periphery of a core portion () of an electromechanical rotor () along an axial direction thereof; inserting coils into the slots (), respectively; forming a plurality of wedges for maintaining the coils in the slots (), respectively; and forming a cut hole () at the core portion () from an outer surface of the core portion () so as to remove at least a deeper area of a crack created at the core portion () at a contacting surface between the corresponding wedge and the corresponding slot ().

Method for repairing a crack in an electromechanical rotor, method for preventing crack growth in the same, electromechanical rotor and rotary electrical machine

An object of the present invention is to control crack propagation, either by predicting shaft dovetail crack propagation with high accuracy, or by determining operation conditions under which the crack does not extend. The crack propagation prediction system includes an operation processing unit, an interface unit, and a memory unit. The operation processing unit includes a stress calculation unit that calculates the mean stress generated in the shaft dovetail, a factor range calculation unit that calculates the stress intensity factor range for the crack in the shaft dovetail, and a crack propagation amount calculation unit that calculates an amount of the shaft dovetail crack propagation for an arbitrary time period, from the obtained mean stress and the stress intensity factor range, an operation pattern, an operation time, and data on the crack. The stress calculation unit includes as individual calculation units that calculate separately different types of mean stress, a contact surface pressure stress calculation unit, a thermal stress calculation unit, and a residual stress calculation unit, as well as a mean stress calculation unit that sums these mean stresses.

Predicting crack propagation in the shaft dovetail of a generator rotor

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Yokohama, Japan

Ryoji Nagano