When maximum values of the design factors are considered, what is the relation between flux and the magnetizing current?

When considering the maximum values of the design factors for electrical machines or transformers, the flux ((Phi)) and the magnetizing current ((I_m)) are related by the core material’s magnetization curve or B-H curve. As you increase the magnetizing current, the flux in the core also increases, but this relationship is not linear due to the magnetic saturation of the core material.

Initially, at lower levels of magnetizing current, the flux increases almost linearly with an increase in current, indicating a relatively constant relationship. This is because the core material is in the linear portion of its B-H curve, where permeability ((mu)) is nearly constant.

However, as the magnetizing current increases further and approaches its maximum value that the design can handle, the core material begins to saturate. During saturation, even small increases in the magnetizing current can lead to very small increases in flux. This means the relationship changes such that further increases in the magnetizing current result in diminishing increases in flux. The core’s permeability decreases significantly in this region, making it harder to increase flux with the same ease as before saturation.

In summary, the relation between flux ((Phi)) and magnetizing current ((I_m)) demonstrates a nearly linear increase at low levels of current, followed by a nonlinear relationship as the magnetizing current approaches its maximum value and the core material enters saturation. In the saturation region, significantly higher increments of magnetizing current are needed to