The AC induction motor is often referred to as the workhorse of
the industry because it offers users simple, rugged
construction, easy maintenance, and cost-effective pricing.
These factors have promoted standardization and development of a
manufacturing infrastructure that has led to a vast installed
base of motors; more than 90% of all motors used in worldwide
industry are AC induction motors.  In spite of this popularity,
the AC induction motor has two basic limitations. The standard
motor is neither a true constant-speed machine, nor is it
inherently capable of providing variable-speed operation. Both
limitations require consideration, as the quality and accuracy
requirements of motor/drive applications continue to increase.
This article will explore the reason for slip and discuss ways
to minimize it. In addition, it will detail the best methods now
available for controlling motor speed with power electronics,
including technology to minimize the negative effects of slip.
Motor slip is necessary for to