A system and method for testing an electrical generator of the type having a rotor (14) and a stator (12) includes or utilizes a movable carriage (22) having testing equipment which is sized to fit between the rotor (14) and stator (12) and is positionable over a selected stator (12) slot so as to be able to axially traverse the selected stator (12) slot, at least one sensor for sensing whether the movable carriage (22) is centered in an optimum position with respect to the selected stator (12) slot; and structure for centering the movable carriage (22) with respect to the optimum position if the sensor indicates the movable carriage (22) is not so centered, whereby accuracy of any testing by the testing equipment is optimized.