ABB ACS880-04 drive modules - Checking the Total Charging Resistance

Planning – basics 23
Checking the total charging resistance
Use this method for verifying the charging capacity if there are only drives with Type A
charging circuits in the common DC system.
The total charging resistance must comply with this formula:
R
tot
> R
min
Calculate the value R
tot
as follows:
Define the value R
min
as follows:
1. If you connect only one drive to the AC power line, R
min
is equal to the minimum
charging resistance defined for that drive. See section Charging resistance values on
page 43.
2. If you connect several drives to the AC power line, calculate R
min
. Use this equation:
R
tot
Calculated total charging resistance for the common DC system.
R
min
Minimum charging resistance allowed for the common DC system.
R
a
Charging resistance of drive a in the common DC system. See section Charging resistance
values on page 43.
R
b
Charging resistance of drive b in the common DC system. See section Charging resistance
values on page 43.
R
min,1
Minimum charging resistance of drive 1 connected to the AC power line. See section
Charging resistance values on page 43.
R
min,2
Minimum charging resistance of drive 2 connected to AC power line. See section Charging
resistance values on page 43.
R
tot
R
a
1
R
b
1
R
n
1
+++
1
=
…
R
min
R
min,1
1
R
min,2
1
R
min,n
1
+++
1
=
…