What is hysteresis loss in motor?

Definition: The work done by the magnetising force against the internal friction of the molecules of the magnet, produces heat. This work, done by the magnetising force produces heat; thereby causing wastage of energy in the form of heat is termed as hysteresis loss. …

What are hysteresis losses?

Hysteresis loss is caused by the magnetization and demagnetization of the core as current flows in the forward and reverse directions. A hysteresis loop shows the relationship between the induced magnetic flux density (B) and the magnetizing force (H). … It is often referred to as the B-H loop.

What is hysteresis loss and eddy current loss?

The most significant difference between the Eddy current and Hysteresis loss is that the eddy current loss occurs because of the relative motion between the conductor and the magnetic field. Whereas the hysteresis loss occurs because of the reversal of the magnetism.

How does hysteresis loss occur?

Hysteresis loss in a transformer occurs due to magnetization saturation in the core of the transformer. Magnetic materials in the core will eventually become magnetically saturated when they are placed in a strong magnetic field, such as the magnetic field generated by an AC current.

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What is the use of hysteresis loss?

The applications of hysteresis loss include the following. The hysteresis loop provides the data of coercivity, retentivity, susceptibility, permeability & loss of energy throughout a single cycle of magnetization for every ferromagnetic material.

How can hysteresis loss be reduced in motors?

To reduce hysteresis losses, most DC armatures are constructed of heat-treated silicon steel, which has an inherently low hysteresis loss. After the heat-treated silicon steel is formed to the desired shape, the laminations are heated to a dull red and then allowed to cool.

What does hysteresis mean?

Hysteresis is the dependence of the state of a system on its history. … Hysteresis occurs in ferromagnetic and ferroelectric materials, as well as in the deformation of rubber bands and shape-memory alloys and many other natural phenomena.

How can eddy current loss be reduced?

Eddy current magnitude can be reduced by designing the core as a set of thin sheets or laminations, in parallel to the magnetic field. … Eddy currents can also be reduced by using a magnetic material such as silicon steel, with a higher resistivity.

What is a eddy current loss?

These circulating currents are called Eddy Currents. … They will occur when the conductor experiences a changing magnetic field. As these currents are not responsible for doing any useful work, and it produces a loss (I2R loss) in the magnetic material known as an Eddy Current Loss.

How can we reduce the hysteresis and eddy current losses?

Conclusion: hysteresis Losses can be reduced by special core material which reached to zero or near zero flux density after removal of current. Eddy current Losses can be reduced by making core by thin sheets by reducing the area of each Eddy current branch.

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What is the effect of hysteresis?

The magnetization of ferromagnetic substances due to a varying magnetic field lags behind the field. This effect is called hysteresis, and the term is used to describe any system in whose response depends not only on its current state, but also upon its past history.

What is hysteresis loop explain with diagram?

A hysteresis loop shows the relationship between the induced magnetic flux density B and the magnetizing force H. It is often referred to as the B-H loop. … This is referred to as the point of retentivity on the graph and indicates the remanence or level of residual magnetism in the material.

How does hysteresis loss depend on frequency?

Hysteresis losses are proportional to the electrical frequency and the eddy current losses are proportional to the square of the electrical frequency.

Does the thickness of laminations affect hysteresis loss?

The hysteresis losses are also related to grain sizes. The larger the grain size, the lower the hysteresis loss. The eddy-current losses vary as the square of the “lamination” thickness, and in order to keep the eddy-current losses low, the thickness of laminations must be kept as low as is economically feasible.

What is meant by retentivity?

: the power of retaining specifically : the capacity for retaining magnetism after the action of the magnetizing force has ceased.

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