US 9,810,743 B2
Deterioration diagnosis system
Kohji Maki, Tokyo (JP); Shinya Yuda, Tokyo (JP); Hiroaki Kojima, Tokyo (JP); Satoshi Kikuchi, Tokyo (JP); and Hisashi Endo, Tokyo (JP)
Assigned to Hitachi, Ltd., Tokyo (JP)
Filed by Hitachi, Ltd., Chiyoda-ku, Tokyo (JP)
Filed on May 8, 2015, as Appl. No. 14/707,245.
Claims priority of application No. 2014-099214 (JP), filed on May 13, 2014.
Prior Publication US 2015/0331051 A1, Nov. 19, 2015
Int. Cl. G01R 31/14 (2006.01); G01R 31/00 (2006.01); G01R 31/34 (2006.01); G01M 13/04 (2006.01); G01R 31/12 (2006.01); G01R 31/02 (2006.01)
CPC G01R 31/343 (2013.01) [G01M 13/04 (2013.01); G01R 31/34 (2013.01); G01R 31/025 (2013.01); G01R 31/12 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A deterioration diagnosis system configured to diagnose deterioration of an N-phase rotational machine (N denotes a natural number), comprising:
a first current sensor to be attached individually to at least lead wires of (N-1)-phases in the rotational machine, so as to detect a current amplitude arising from a plurality of deterioration causes;
a second current sensor to be attached collectively to the lead wires of all phases in the rotational machine, so as to detect a current amplitude arising from a plurality of deterioration causes; and
a third current sensor attached collectively to ground wires connected individually to the lead wires of each of the phases, wherein
the first current sensor and the second current sensor detect a current amplitude in a frequency band ranging from 0 Hz to 100 MHz, and
the third current sensor detects a current amplitude in a frequency band from 1 MHz and over.