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Why does inductor produce back emf?
The back EMF is produced because the changing current in the inductor causes a changing magnetic field around it and the changing magnetic field causes, in turn, an EMF to be induced back into the inductor. This process is called SELF INDUCTION.
How is emf induced in inductor?
An inductor typically consists of an insulated wire wound into a coil. When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (e.m.f.) (voltage) in the conductor, described by Faraday’s law of induction.
How does an inductor generate back EMF in a circuit?
If external emf and induced emf are same then the energy given to electrons in completing the circuit is equal to the energy taken by the inductor from the electrons then how is their kinetic energy (current) increasing? One way to think of a inductor from the circuit’s point of view is that it gives inertia to current.
What happens when the back EMF equals the applied EMF?
So the rate of current increase rises until the back emf of the inductor equals the applied emf. Additionally, since nothing prevents instantaneous changes in rate of change of current, the circuit can equilibrate to steady state (of constantly increasing current) instantly.
How is induced voltage applied to an inductor?
Suppose we have a circuit with a voltage source, a switch open and an inductor all in series. If we close the switch, the potential difference of the voltage source is instantaneously applied to the inductor. As the current starts to build up, induced voltage from the inductance opposes it.
What is the voltage of a back EMF motor?
Under normal operating conditions for this motor, suppose the back emf is 40.0 V. Then at operating speed, the total voltage across the coils is 8.0 V (48.0 V minus the 40.0 V back emf), and the current drawn is I = V/R = (8.0 V)/ (0.400 Ω) = 20 A.