Working Principle of Inductors
When a voltage differential is applied across an inductor’s leads, the inductor converts electricity into an electromagnetic field. When the voltage differential is removed from the leads, the inductor will attempt to maintain the amount of electrical current flowing through it. It will discharge when the electromagnetic field collapses, or if an electrical pathway is created between the two inductor leads.
We can take an electric motor as common example in which the load is used to convert electricity into physical work. It generally requires more power to start turning the rotor than it requires to keep an already-turning rotor in motion, and when voltage is applied to the leads on an electric motor the motor generates a change in magnetic flux. This change induces an electromotive force that opposes the forward-turning force that would start the motor turning, and this phenomenon is called a back electromotive force. After several seconds, an electric motor will have overcome the some of the impedance, and will function as designed.