For many years AC motors have been used strictly in constant speed applications. The flow control was also performed with pumps, fans and compressors through mechanical means such as the throttling of valves and dampers. When variable speed baldor cm3542 was requested on DC motors along with turbines, internal combustion engines were chosen. The beginnings of variable speed drives, reliable and cost effective, quickly changed these procedures. These motor speed control drives, controlling the voltage and frequency of the mains, have broadly extended the range of applications and capacities of AC motors.

The use of adjustable frequency controls impacts the design, performance and reliability of AC motors, but many effects are positive, such as low speeds that mean smaller cycles of bearings, fans and other rotating elements.

Smooth starting of an engine extinguishes the high starting forces on the stator windings and rotor bars which are common when starting occurs directly in the network. Adjustable frequency drives can positively influence the life of the motor when properly applied. There are, however, a few important factors that should be considered when using motors with these drives.