Hitachi, Ltd.

Hitachi Service Eng., Co. Ltd.

Masao Ohi

Takashi Watanabe

Ryoichi Shiobara

Koji Tanaka

Yoshio Takikawa

Satoshi Oouchi

Yasuto Kondoh

Masayuki Furuyama

A method of adjusting a thermal balance of a rotor. When obtaining a difference in shaft-vibration component of the rotor between an actual load condition and a no load condition, on the basis of detection results at a simulated load, a difference in shaft-vibration component of the rotating rotor between a no-load condition and a condition in which the rotor is heated from the outside and a difference in shaft-vibration component of the rotating rotor between a no-load condition and a condition in which the rotor is heated from the inside are detected at the simulated load. The detected differences in shaft-vibration component are converted respectively to differences in shaft-vibration component under a temperature condition at the actual load. Both the converted differences in shaft-vibration component are added to each other in a vector manner to obtain a difference in rotor shaft-vibration component at the actual load. Coolant flow rate at each section within the rotor is adjusted to eliminate the difference in rotor shaft-vibration component, thereby adjusting the thermal balance of the rotor.

Method of adjusting thermal balance of rotor

A fault diagnosis system for a rotor winding of rotary electric machines is disclosed, in which the rotor winding of rotary field type is excited in DC fashion by an excitation circuit, on which an AC voltage is superposed, the impedance of the rotor winding is calculated from the current and voltage of the AC portion flowing in the rotor winding, and the resulting impedance is compared with a reference impedance thereby to decide a fault, if any, of the rotor winding, thus making possible accurate diagnosis of a rotary electric machine even while it is running.

Fault diagnosis system for rotor winding of rotary electric machine

A current-collecting brush apparatus is disclosed in which brushes are held slidably on a brush holder and pressed against a rotor by a brush-pressing spring. Pigtails connected to supply current to the brushes comprise a plurality of spiral conductors in parallel which are connected by being coiled in mutual opposite directions to offset the magnetic fluxes generated therein.

Current-collecting brush apparatus

Growing community of inventors

Mito, Japan

Masao Ohi