Patent ID: 8564284

Claim:
A method of evaluating the condition of a laminated core of an electric machine, comprising: positioning a magnetic flux injection excitation yoke extending between a pair of teeth of the laminated core, the excitation yoke having a pair of arms in engagement with the pair of teeth, and the excitation yoke being wound with an excitation winding for producing a magnetic flux excitation; supplying power to an electrical circuit defined by the excitation winding to produce a magnetic flux in the excitation yoke and to form a magnetic circuit through the excitation yoke and the laminated core; measuring a characteristic of the electrical circuit of the excitation winding to identify a fault in the magnetic circuit corresponding to an eddy current between individual laminations in the laminated core; and wherein measuring the characteristic of the electrical circuit of the excitation winding includes determining a variation in the characteristic in the excitation winding corresponding to the fault in the magnetic circuit relative to a determination of the same characteristic measured in the excitation winding for a magnetic circuit created through the excitation yoke and a portion of the laminated core without a fault.