Meet the Hibot GEEP Robot: an inspection robot that can fit through a small gap of 0.9 inches but can also adapt to wide spaces of up to 6 inches. It has a high resolution camera for visual inspection. It is autonomous and can be used with sensors to do more. It creates a 2D or 3D map of the generator rotor and can be used to pinpoint the location of defects inside the generator.
The above video shows GEEP by Hibot in action. More info is available here.