Hysteresis loss is a type of energy loss that occurs in magnetic materials due to the repeated magnetization and demagnetization cycles. This phenomenon is particularly important in applications involving alternating current (AC) electromagnetic devices, such as transformers and inductors.
Hysteresis loss is quantified by the area of the hysteresis loop on the B-H (magnetization curve) graph of a magnetic material. The hysteresis loop represents the relationship between the magnetic flux density (B) and the magnetic field strength (H) applied to the material. The loop is closed, meaning that the material returns to its original state after each cycle, but energy is dissipated in the process.
To calculate hysteresis loss, you need to integrate the area enclosed by the hysteresis loop on the B-H graph. The equation for hysteresis loss (Ph) is given by:
Ph = Bmax * Hmax * V * f * Kh
Where:
Bmax is the maximum flux density (maximum value of B) within the hysteresis loop.
Hmax is the maximum magnetizing field (maximum value of H) within the hysteresis loop.
V is the volume of the magnetic material.
f is the frequency of the alternating magnetic field.
Kh is a material-dependent constant.
Please note that the value of Kh depends on the material properties and can vary for different types of magnetic materials. It is typically determined empirically through experimentation or provided by material manufacturers.
Keep in mind that hysteresis loss is only one component of the total energy losses in magnetic materials. Other factors, such as eddy current losses and dielectric losses, also contribute to the overall energy dissipation in electromagnetic devices.
When designing magnetic circuits or electromagnetic devices, it's essential to consider these energy losses to ensure efficient and reliable operation. Proper material selection, geometry design, and operating conditions can help minimize hysteresis losses and improve the overall performance of the devices.