gefran SIEIDrive AVy Series - Page 88

AVy - HGB
Ch.5 88
NOTE! When connecting the intermediate circuit terminals C and D the AC Input side must be
protected with superfast semiconductor fuses!
Formula for calculating the size of the external capacitors:
fA018
Cext =
2 P
SMPS t Buff 10
6
U
2
Buff
- U
2
min
-Cstd
C
ext
, C
std
[μF]
P
SMPS
[W] U
Buff
= 400 V at U
LN
= 400 V
t
Buff
[s] U
Buff
= 460 V at U
LN
= 460 V
U
Buff
, U
min
[V] U
min
= 250 V
Calculation example
An AVy4220 Drive is operated with an AC Input supply U
LN
= 400 V. A voltage failure buffer is required for
max. 1.5 s.
P
SMPS
70 W t
Buff
1.5 s
U
Buff
400 V U
min
250 V
C
std
1800 μF
C ext =
(400 V)
2
- (250 V)
2
-1800mF=2154 mF-1800mF=354mF
2 .70 W.1.5s .10 F/F
6
m