A stack of transformer laminations has relative permeability (linear over the range…

PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Magnetic materials · Magnetic materials

The Boundary-Value Problem, Ch Ferromagnetism: the Weiss field, domains, hysteresis and the magnetic circuit

Problem

A stack of transformer laminations has relative permeability

\mu_r = 2000

(linear over the range used) and carries

H = 150\,\mathrm{A\,m^{-1}}

. ((a)) Find

B

and the work done per unit volume by the winding's source in raising

H

linearly from zero to this value. ((b)) On its measured loop,

B

falls to

0.9\,\mathrm{T}

when

H

is brought back to zero from saturation, and a reversed field of

5\,\mathrm{A\,m^{-1}}

brings

B

to zero. Give the remanence and the coercivity. ((c)) The loop encloses

20\,\mathrm{J\,m^{-3}}

per cycle. For a stack of volume

0.02\,\mathrm{m^3}

driven at

50\,\mathrm{Hz}

, find the power dissipated.