Which of the following two losses are together called core loss?

Question

Question

This question was previously asked in

ALP CBT 2 Electrician Official Paper (Held On: 23 Jan 2019 Shift 3)

Answer 1

Iron losses are caused by the alternating flux in the core of the electrical machine as this loss occurs in the core it is also known as core loss. Iron loss is further divided into hysteresis and eddy current loss.
As the armature core of electrical machine is made of iron and it rotates in a magnetic field, a small current gets induced in the core.
Due to this current, eddy current loss and hysteresis loss occur in the armature iron core.
Iron losses are also called as core losses or magnetic losses.
These are constant losses and independent of load.

Eddy current loss is given by,

Pe = K f2 B2mt2 V

Hysteresis loss occurring in a material is

Ph = η f B1.6mV

Where,

K - Co-efficient of eddy current. Its value depends upon the nature of magnetic material

Bm - Maximum value of flux density in Wb/m2

t - Thickness of lamination in meters

f - Frequency of reversal of magnetic field in Hz

V - Volume of magnetic material in m3

η is Steinmetz's constant (or) hysteresis constant