ABB ACSM1 - Multiple AC Input; Charging Current

16
Multiple AC input
Define R
tot
as in the previous case. Define the effective total minimum
resistance as follows.
•
nminmin
min
RRR
R
111
1
21
+++
=

R
min
values (R
min1
, R
min2
,…) are the individual minimum resistance values of
the drive modules connected to the AC supply.
The following condition must be fulfilled:
• R
tot
> R
min
Charging current
Typical AC input line current waveform and the DC link voltage during the
charging is shown in the figure below.
It must be checked that the AC supply side components (fuses, contactors,…)
can withstand the peak current.
The peak current I
ac,peak
is calculated as follows.
•
tot
ac
peak,ac
R
U
I
×
=
2
where the U
ac
is the line to line supply voltage. The charging time is
generally about 0.3 s (U
dc
> 95% U
dcN
) with ACSM1 drive modules.
I
ac,peak