Apparatus and method for inpact testing for electric generator stator wedge tightness

A method of measuring the tightness of stator wedges in the stator of an electric generator without removing the rotor, the method comprising the steps of:

• i. providing a calibration test stand comprising a section of coils, filler material, and wedges substantially similar to that of the electric generator to be measured;
• ii. preloading said section of coils, filler material, and wedges of the calibration test stand with a first range of predetermined forces measured at the load source and generating a plurality of force-displacement curves obtained by impacting said wedges of the calibration test stand with a second range of forces measured at an impact point and measuring the wedge displacement caused thereby;
• iii. calculating a plurality of curve equations from said plurality of force-displacement curves;
• iv. striking one of said stator wedges to cause a displacement thereof;
• v. measuring the force used to strike the one stator wedge to generate force data;
• vi. measuring displacement of the one stator wedge in response to being struck to generate displacement data;
• vii. comparing said generated force and displacement data with said plurality of forcedisplacement curves to determine the tightness of the one wedge in said stator.

Apparatus for measuring the tightness of stator wedges in the stator of an electric generator without removing the rotor, said apparatus comprising:

• a low profile carriage insertable in a narrow gap between the rotor and stator and successively positionable adjacent selected stator wedges;
• an impactor carried by said low profile carriage, said impactor striking the selected stator wedge to cause a displacement thereof;
• and
• sensor means mounted on said low profile carriage for directly measuring the peak-to-peak amplitude displacement of the selected stator wedge in response to being struck by said impactor.