Electrostatic capacity measuring instrument for stator winding of electric rotating machine

摘要

An electric rotating machine comprises a rotor body (57) of cylindrical structure and a stator body (50) covering an outer peripheral portion of the rotor body (57) in a non-contact fashion. The stator body (50) includes a stator winding (55) formed with an insulation layer and arranged radially outward of the rotor body (57) with a clearance from the rotor body and a stator core which supports the stator winding. The electrostatic capacity of the stator winding is measured by an electrostatic capacity measuring instrument which comprises a housing (2) having a size allowing the housing to be accommodated in the clearance between the rotor body (57) and the stator winding (55), a support body (1) detachably secured to the rotor body (57) and adapted to support the housing (2) within the clearance to be movable, and a measuring element (3) mounted to the housing (2) on the side of the housing facing the stator winding (55) and adapted to measure electrostatic capacity of the stator winding, wherein a degree of water penetration into the insulation of the stator winding is determined based on a measurement data from the measuring element.