1. A method for detecting faults in a laminated core of an electric machine, comprising: (a)positioning a pair of magnetic flux injection yokes near at least one tooth of the core, the yokes being arranged side-by-side in close proximity to each other, each yoke having a pair of flux injecting arm portions and each yoke being wound with a magnetic flux excitation winding and having a flux sensor on at least one of the arm portions; (b)supplying current to the flux injection winding of at least one yoke to inject magnetic flux into the at least one tooth of the core; (c)measuring a flux difference signal obtained between two adjacent flux sensors, each flux sensor of the two sensors from which the difference signal is obtained being located on a different yoke; and (d)using the measured flux difference signal to detect a core lamination fault.