How does a DC servo motor work?

Hello Goel

This is a link to an article describing what is a servo (system) (http://www.seattlerobotics.org/guide/servos.html)

Another link with more details on the electronics involved in servo motors (http://www.electricmotors.machinedesign.com/guiEdits/Content/bdeee4a/bdeee4a_1.aspx)

This is a permanent magnet dc motor which hence could be rotated in cw or ccw directions. Used for governors of high power engines to control their speed from control panel.