
8-6 Power Electronics and Motor Drives
e amount of the emitted heat depends on the absolute temperature of the body. e Stefan-
Boltzmann’s law denes the convection heat transfer phenomenon:
Q AT= σ
4
(
8.6)
where
Q [W] is the rate of heat transfer
A [m
2
] is the surface area of perfectly radiating body
σ
[
W/(m
2
K
4
)] is the Stefan-Boltzmann constant equal to 5.669 × 10
−8
T [K] is the absolute surface temperature
An
i
deal
r
adiating
b
ody
(
technically
d
ened
a
s
“
black
b
ody”)
e
mits
a
t
a
g
iven
t
emperature
t
he
m
axi-
mum
p
ossible
e
nergy
a
t
a
ll
w
avelengths.
e
St
efan-Boltzmann
e
quation
d
enes
t
he
e
nergy
e
mission
r
ather
t
han
t
he
e
nergy
e
xchange.
S
ince ...