
60 Shipboard Electrical Power Systems
Regarding the magnetic loss, the alternating magnetic ux produces two types
of power loss in the ferromagnetic iron core: (1) hysteresis loss P
hyst
= K
h
f B
m
n
due
to hysteresis (magnetic friction), and (2) eddy current loss P
eddy
= K
e
f
2
B
m
2
t
2
due to
internally circulating (eddy) currents in the core body. Here, K
e
and K
h
= propor-
tionality constants, f = frequency, B
m
= maximum (peak) ux density, t = thickness
of the core laminations perpendicular to the ux ow, and n = Steinmetz constant
(typically 1.6 to 1.8 for magnetic steel used in electrical machines).
Since P
eddy
depends on the core laminat