Datasheet

Aluminium Electrolytic Capacitors
7
Factor Kc for forced cooling of the cap
0
0,2
0,4
0,6
0,8
1
0 1 2 3 4 5
Air velocity [m/s]
Kc
C
*
hs
R
*
h_c
R
*
c_hs
K
c
* R
*
c_a
C
*
cap
K
hs
* R
*
hs_a
T
h
T
c
T
hs
T
a
T
a
ESR = Equivalent series resistance C*
cap
= Thermal capacity of the cap
I
~
= Ripple current load C*
hs
= Thermal capacity of the heatsink
P
L
= Internal losses R*
h_c
= Thermal resistance hotspot - case
U
DC
+U
AC
= Applied voltage R*
c_hs
= Thermal resistance case - heatsink
T
h
= Hotspot temperature R*
c_a
= Thermal resistance case - ambient
T
c
= Case temperature R*
hs_a
= Thermal resistance heatsink - ambient
T
a
= Ambient temperature K
c
= Factor for forced cooling of the cap
T
hs
= Heatsink temperature K
hs
= Factor for forced cooling of the heatsink
ESR
I
~
P
L
= ESR * I
~
2
U
DC
+
U
AC
heatsink
2
~
*
LossesInternal
IESR
L
P
*
_
*
_
*
_
*
_
*
_
*
_
*
_
*
_
**
***
ambient -hotspot resistance Thermal
ahshshscacc
ahshshscacc
chah
RKRRK
RKRRK
RR
cap theon depends
W/ 1,0
GW seriefor Values
*
*
_
cap
hsc
C
R
lossesTransient
0 if
*
with
)1(**
over time mperatureHotspot te
*
_
***
_
*
_)()(
)function stepcurrent (
L
hsc
hscapah
th
t
ahLtohth
P
R
CCRth
eRPTT
c
W/ 2,2
W/ 7,0
98*90 Can
*
_
*
_
ac
ch
R
R
W/ 6,2
W/ 6,0
69*90 Can
*
_
*
_
ac
ch
R
R
W/3,3
W/6,0
69*75Can
*
_
*
_
ac
ch
R
R
W/3,5
W/6,0
69*50Can
*
_
*
_
ac
h
R
R
5. Thermal Model
BACK TO INDEX
BACK TO START