Apparatus for impact testing for electric generator stator wedge tightness
First Claim
1. 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 set up a mechanical vibration therein; and
a vibration detector mounted on said low profile carriage, said vibration detector comprising;
a wedge follower which bears against and follows said selected stator wedge as said wedge vibrates in response to being struck by said impactor, said wedge follower being at least in part electrically conductive; and
an eddy current coil positionable at a stationary point spaced from said wedge follower generating an electrical signal which varies with changes in spacing between the wedge follower and the eddy current coil as said wedge follower vibrates with said selected stator wedge.
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Accused Products
Abstract
A low profile remotely controlled carriage which is inserted between the rotor and stator of an electric generator carries an impactor which can be preloaded to strike the stator wedges in all orientations around the stator with a selected high impact force which causes the stator wedge to vibrate. A detector seismically isolated from the impactor measures the deflections in the vibrating stator wedge. Preferably, the detector includes an eddy current coil positioned to measure the distance to a wedge follower which vibrates with the wedge. In one embodiment, the wedge follower is a vacuum cup secured to the wedge. In another, the eddy current coil measures the distance to a foot spring biased against the vibrating wedge. Preferably, the detector is seismically isolated by mounting it on a separate carriage disposed in an aperture in the low profile carriage.
41 Citations
29 Claims
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1. Apparatus for measuring the tightness of stator wedges in the stator of an electric generator without removing the rotor, said apparatus comprising:
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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 set up a mechanical vibration therein; and a vibration detector mounted on said low profile carriage, said vibration detector comprising; a wedge follower which bears against and follows said selected stator wedge as said wedge vibrates in response to being struck by said impactor, said wedge follower being at least in part electrically conductive; and an eddy current coil positionable at a stationary point spaced from said wedge follower generating an electrical signal which varies with changes in spacing between the wedge follower and the eddy current coil as said wedge follower vibrates with said selected stator wedge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for measuring the tightness of stator wedges in the stator of an electric generator without removing the rotor, said apparatus comprising:
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a low profile remotely controlled 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 set up a mechanical vibration therein; a vibration detector carried by said low profile carriage detecting deflection of the selected stator wedge as said wedge vibrates in response to being struck by said impactor; and means seismically isolating said vibration detector from said impactor. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. Apparatus for measuring the tightness of stator wedges retaining stator coils in stator slots distributed around the interior of a horizontally oriented electric generator stator without removing the generator rotor, said apparatus comprising:
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a low profile carriage insertable in a narrow gap between the rotor and stator and successively positionable adjacent selected stator wedges in selected stator slots; an impactor carried by said low profile carriage and having an impactor head which strikes said selected stator wedge setting up a mechanical vibration therein, and means applying to said impactor head a driving force adjusted for the effect of gravity on the impactor head such that said impactor head strikes the selected stator wedge with a selected force at all stator slots around said horizontally oriented stator; and a vibration detector carried by said low profile carriage detecting deflection of the selected stator wedge as said wedge vibrates in response to being struck by said impactor head with said selected force. - View Dependent Claims (28, 29)
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Specification