Generator rotor slot wedges are generally installed between rotor teeth to hold the copper windings in place. During the course of operation one or more wedges may develop flaws, e.g., surface cracks, which may lead to a failure of the generator. Inspection of the rotor wedge surface is therefore recommended for maintaining generator operability. Cracks initiating from the side of the rotor wedges are generally not accessible for a surface inspection, or more particularly a volumetric inspection, without removing the rotor. One of the difficulties in inspecting the rotor wedges without removing the rotor is that there is a small clearance, e.g., as little as between 0.6 inch (1.52 cm) and 1.5 inches (3.81 cm), between the stator bore and the rotor retaining ring through which an apparatus may be inserted to inspect the wedges distributed along the length of the stator. Because of this limited clearance, inspection is typically performed by removing the generator rotor from the stator frame to provide access to the rotor wedges, while the wedges remain installed in the rotor. This method of inspection, i.e., by removing the rotor, requires a significant amount of time during the outage, and increases the risk of damage to the rotor and stator.
Therefore, there remains a need for a more efficient means of inspecting the rotor wedges without having to remove the generator rotor, and risking damage to the rotor and stator.