The cylindrical grinder is a type of grinding machine used to shape the outside of an object. The cylindrical grinder can work on a variety of shapes, however the object must have a central axis of rotation. This includes but is not limited to such shapes as a cylinder, an ellipse, a cam, or a crankshaft.
Electric motors, generators, alternators and loudspeakers are explained using animations and schematics. This is a resource page from Physclips, a multilevel multimedia introduction to physics (download the animations on this page).