how histerisis curve is useful in deciding particular type of magnets required for transformers etc?

CBSE Class 12-science Answered

how histerisis curve is useful in deciding particular type of magnets required for transformers etc?

Asked by Potam Mahesh | 08 Oct, 2014, 09:09: PM

Expert Answer

The main use of the study of hysteresis curve of a material is that it gives an estimate of the hysteresis loss. The study of hysteresis curve helps in knowing the retentivity and coercivity of the material. Their knowledge helps in selecting the proper material for making the core of transformers, permanent magnets and electromagnets.

Hysterisis is the phenomena of lagging of magnetic induction (B) and intensity of magnetisation (I) behind the magnetisisng field(H), when the specimen is taken through a cycle of magnetisation.

The core of a transformer undergoes cycles of magnetisation again and again. During each cycle of magnetisation, energy numerically equal to the area of the hysteresis loop is spent per unit volume of the core. Therefore for high efficiency of the transformer, the energy loss should be lesser (the hysteresis loop should be of lesser area i.e narrow) . Since soft iron has a narrow hysteresis loop, it should be used as the core of a transformer.

Thus from the hysterisis loop of a material, we can study about retentivity, coercivity etc of the material. The loss of energy per unit volume of the specimen per cycle of magentisation is equal to the area of the I-H loop or the area of B-H loop of the specimen. The study of these characteristics enables us to select suitable materials for different purposes.

Answered by Jyothi Nair | 09 Oct, 2014, 09:23: AM