Synchronous Speed

the common value of the speed for a group of objects moving in synchronism. When the speed of any object deviates from this value, the object is said to fall out of synchronism or to slip relative to the other objects. The quantity known as slip is the quotient obtained when the difference between the synchronous speed and the speed of a slipping object is divided by the synchronous speed. In electrical engineering, the synchronous speed of a synchronous machine is the rotational speed equal to the quotient of the AC frequency in the winding divided by the number of pole pairs.