22-07-2014, 12:13 PM
MARATHWADA INSTITUTE OF TECHNOLOGY
INSTITUTE OF TECHNOLOGY.pptx (Size: 97.53 KB / Downloads: 9)
INTODUCTION
An electric motor is an electromechanical device that converts electrical energy intomechanical energy.
Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force.
OPERATION PRINCIPLE
When current carrying conductor is place in a magnetic field it experience a force causing torque.
DC MOTOR
A DC motor is designed to run on DC electric power. Two examples of pure DC designs are Michael Faraday's homopolar motor (which is uncommon), and the ball bearing motor, which is (so far) a novelty.
AC MOTOR
Ac motors are designed for ac electric current. An AC motor has two parts: a stationary stator having coils supplied with alternating current to produce a rotating magnetic field, and a rotor attached to the output shaft that is given a torque by the rotating field.
BACK EMF
During operation the conductors that make up the coils of a motor will see external varying magnetic fields, either due to their own motion, or the movement or varying of other magnets, and these generate electrical potentials across the coils called 'back EMF' that are in the opposite direction to the power supply, and are proportional to the running speed of the motor
APPLICATION OF MOTOR
Electrical motors are use in industries and homes like single phase induction motor ,servomotor etc.
Motor can be used as a generator by using the reverse principle of motor