System and method for evaluating the condition of an electric machine

A method of detecting a short circuit between a first lamination and a second lamination in a plurality of laminations arranged along a longitudinal axis to define a stator core, the method comprising:

• surrounding a portion of the plurality of laminations with a first coil of a sensor coil disposed in a plane that is parallel to the longitudinal axis;
• measuring a first signal from the sensor coil;
• comparing the first signal to a second signal to identify a difference;
• and
• indicating the existence of the short circuit in response to the difference.

An electric machine comprising:

• a plurality of laminations stacked along a longitudinal axis;
• a plurality of insulation layers arranged such that one insulation layer is disposed between adjacent laminations of the plurality of laminations;
• a first coil positioned to surround the plurality of laminations and the plurality of insulation layers and arranged on a first side of the longitudinal axis in a plane that includes the longitudinal axis;
• a second coil positioned to surround the plurality of laminations and the plurality of insulation layers and arranged on a second side of the longitudinal axis in the plane, the second side on the opposite side of the longitudinal axis as the first side, the first coil and the second coil connected in series;
• a detector electrically connected to the first coil and the second coil to measure a first signal and to compare the first signal to a reference signal, a difference between the first signal and the reference signal being indicative of a damaged insulation layer.