Electric drives concepts and applications pdf
Electric Drives and their Applications by Dr. S. Chatterji on 02 September 2013
Electric Drives: Concepts And Applications
A stepper motor , also known as step motor or stepping motor , is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor's position can then be commanded to move and hold at one of these steps without any position sensor for feedback an open-loop controller , as long as the motor is carefully sized to the application in respect to torque and speed. Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated. Brushed DC motors rotate continuously when DC voltage is applied to their terminals. The stepper motor is known by its property of converting a train of input pulses typically square wave pulses into a precisely defined increment in the shaft position. Each pulse moves the shaft through a fixed angle. Stepper motors effectively have multiple "toothed" electromagnets arranged around a central gear-shaped piece of iron.
The classification of electrical drives can be done depending upon the various components of the drive system. Now according to the design, the drives can be classified into three types such as single-motor drive, group motor drive and multi motor drive. The single motor types are the very basic type of drive which are mainly used in simple metal working, house hold appliances etc. Group electric drives are used in modern industries because of various complexities. Multi motor drives are used in heavy industries or where multiple motoring units are required such as railway transport. If we divide from another point of view, these drives are of two types:. This depends mainly on the capability of the drive system to alter the direction of the flux generated.