The losses related to an inductor can be categorized into two types. One type is entirely dependent on the properties of the core material, while the other type relies solely on the characteristics of the conductor and current flowing through it.
- Copper loss
- Core loss
- Copper losses purely depends on winding wire properties
- Core loss purely depends on magnetic core material properties
Copper losses
When a magnetic bar is inserted into an current carries conductor and the switch is closed, current begins to flow through the winding. It is well-known that every wire possesses some inherent resistance. Due to this internal resistance of the wire, heat is released into the surrounding air. This phenomenon of heat dissipation is referred to as copper loss.
When current flowing through winding, some heat produces due to internal resistance of the wire.
The current flowing through the circuit is influenced by the amount of load connected to it. This means that if the load changes, the current flowing in the circuit will also change accordingly. As a result, copper losses fluctuate with varying loads. Therefore, these losses can be classified as variable losses.
Hysteresis Losses
This loss depends on purely core material properties.
When a magnetic core is positioned around a current-carrying conductor, the dipoles within the magnetic core are oriented randomly before the switch is closed. At this point, no electromotive force (EMF) is generated, and as a result, the bar remains unmagnetized. As shown in below figure.
Once the switch is closed, current starts flowing through conductor around the magnetic core. The dipoles in magnetic core starts coming in one direction and align with current direction. Once all dipoles are in one direction, magnetic core is fully magnetized material as shown middle figure.
When the switch in the circuit is opened, current flow through the conductor stops. As a result, most dipoles in the magnetic core start to revert to their original positions. However, some dipoles remain in their altered states within the core. This means that the core has retained some magnetization, which is why it is referred to as a ferro-magnetized core.
To demagnetise this ferro-magnetic core, extra energy needs to be spent. This needs to happen in every cycle. The extra energy spending in every cycle appears in the form of heat. This heat loss is called as hysteresis loss
The total loss of an inductor can be calculated using below equation,
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