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INTRODUCTION TO MACHINERY PRINCIPLES
2.4 CHAPTER TWO
It can easily be seen that the magnetizing intensity is directly proportional to the magneto-
motive force, and the magnetic flux density is directly proportional to the flux. Therefore,
the relationship between B and H has the same shape as the relationship between the flux
and the magnetomotive force. The slope of flux-density versus the magnetizing intensity
curve (Fig. 2.2c) is by definition the permeability of the core at that magnetizing intensity.
The curve shows that in the unsaturated region the permeability is high and almost constant.
FIGURE 2.2 (a) Sketch of a dc magnetization curve for a ferromagnetic core. (b) The magnetization curve
expressed in terms of flux density and magnetizing intensity. (c) A detailed magnetization curve for a typical
piece of steel.
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