Question

CAn anybody please explain the back emf effect in motors...... I am just a bit confused about it
......

Answer 1

Motors spin when you apply voltage to them, but they also produce voltage when you spin them and act as a generator. So when you connect the motor to a battery, it spins it, but then the act of the motor spinning causes a voltage to be formed backwards!

Answer 2

The emf produced due to the rotation of the coil and the emf of the battery oppose each other's effect? and so this induced emf produced by the rotation of the coil is the back emf effect ? RIght ? OR tell me.......

Answer 3

the armature (that is the rotating part of motor) of motor rotates in the presence of magnetic field... now from the basic principle we know that metal crossing the magnetic field lines or in a more general terms whenever a conductor cuts magnetic field lines there is an induced emf in it....similarly when the armature rotates in a magnetic field it develops its own emf that we call as back emf and this produced back emf causes a current to flow in the armature coil ....that further produces its magnetic field... which opposes the external magnetic field or you can say the applied magnetic field or the rotating magnetic field inside a motor or generator

Answer 4

Effects?

Well...
When a motor runs fast! with or without a load, it stops consuming current from the battery or power source.
It basically becomes a generator. If reached to the maximum potential speed it produces almost the same amount of input voltage. And less current is needed to run the motor.

Answer 5

back EMF increases the apparent resistance of the circuit by providing an opposing voltage, an electric motor that is already spinning consumes less power than one that is starting or changing direction.Since without back emf motor was consuming higher energy V*I ...it was but as soon as back emf comes into action it opposes the voltage and motor consumes less power.....also back emf is used in electric witching !!