Found this article...

"Single-phase induction motors drive many arbor-mounted cutting tools in the
home workshop. Stationary grinders, table and radial arm circular saws
frequently turn abrasive or cutting disks that are directly mounted on the
motor's spindle. These disks have large inertial moments that allow them to
free wheel for a long time after the power is turned off. A lengthy coast to
complete stop often amounts to a major inconvenience."

http://www.homemetalshopclub.org/new...html#reversing