Electrical Engineering ⇒ Topic : Energy Stored in an Inductor

ENERGY STORED IN AN INDUCTOR:-

In general, if current increases non-uniformly, we suppose that the current increases by di ampere in dt seconds. (Assuming inductance to be constant

Energy stored in the magnetic field of the inductor during time dt

                                                                      = Energy supplied in dt seconds = Voltage x Current x Time

Now, as the current increases from 0 to I ampere so

                                                      ..............()

Energy Stored in a Magnetic Field

In order to establish a magnetic field around a coil, energy is *required, though no energy is needed to **maintain it. This energy is stored in the magnetic field and is not used up. When the current is decreased, the flux surrounding the coil is decreased, causing the stored energy to be returned to the circuit. Consider an inductor connected to a d.c. source as shown in Fig.(a) (i). The inductor is equivalent to inductance L in series with a small resistance R as shown in Fig. (a) (ii).

The energy supplied to the circuit is spent in two ways

• A part of supplied energy is spent to meet I²R losses and cannot be recovered.
• The remaining part is spent to create flux around the coil (or inductor) and is stored in the magnetic field. When the field collapses, the stored energy is returned to the circuit

                                                                       figure (a)