Area of hysteresis loop represents: Hysteresis losses

Hysteresis is a phenomenon that occurs in ferromagnetic materials, such as iron, when they are subjected to alternating magnetic fields. It refers to the lagging of the magnetization of a material behind the applied magnetic field. This lagging results in energy losses in the form of heat, known as hysteresis losses.

The hysteresis loop is a graphical representation of the relationship between the magnetic field strength (H) and the magnetic flux density (B) of a ferromagnetic material. It shows how the magnetic flux density changes as the magnetic field strength is varied.

Understanding the hysteresis loop:

The hysteresis loop is a closed loop that starts at the origin and returns to the same point. It consists of two branches: the magnetization curve during magnetization and the demagnetization curve during demagnetization. The area enclosed by the loop represents the energy dissipated as heat during each cycle of magnetization and demagnetization.

Interpreting the area of the hysteresis loop:

The area of the hysteresis loop is directly proportional to the energy loss per cycle, which is known as hysteresis loss. This loss occurs because the magnetic domains in the ferromagnetic material undergo rearrangement as the magnetic field is applied and removed. The energy required for this rearrangement is dissipated as heat.

Significance of hysteresis losses:

Hysteresis losses are undesirable in electrical devices, especially in transformers and motors, as they result in energy wastage and heating of the core material. To minimize hysteresis losses, materials with low hysteresis coefficients, such as electrical steel, are used in the construction of transformer cores.

Other losses in electrical devices:

- Copper losses: These losses occur due to the resistance of the copper windings in electrical devices. They are proportional to the square of the current flowing through the windings and can be minimized by using thicker wires or materials with lower resistivity.

- Iron losses: Also known as core losses, iron losses occur due to two main factors: hysteresis losses and eddy current losses. They represent the energy dissipated in the core material of transformers and other electrical devices.

- Eddy current losses: Eddy currents are circulating currents induced in conducting materials when they are exposed to changing magnetic fields. These currents result in energy losses due to the resistance of the material. Eddy current losses can be minimized by using laminated cores or materials with high electrical resistivity.

In summary, the area of the hysteresis loop represents hysteresis losses, which are energy losses that occur in ferromagnetic materials when they are subjected to alternating magnetic fields.