ABB ACS880-04 drive modules - Selecting the Drives Which Are Connected to AC Power Line; The Selection Rules; Calculating the Rectifier Power Capacity

Planning – basics 21
Selecting the drives which are connected to
AC power line
This section contains instructions for selecting the drives which are connected to the AC
power line. However, you can also connect more drives, for example, for backup reasons.
 The selection rules
1. At the very least, connect the drive with the highest power rating to the AC power line.
Then the second largest, etc. until both the rectifier power capacity and charging
capacity of the system are high enough.
2. Make sure that you connect only the allowed combination of drives to the AC power
line. See section Power correction factor (k) on page 41.
3. Make sure that you have enough rectifier power capacity in the system. See
subsection Calculating the rectifier power capacity on page 21.
4. Make sure that you have enough charging capacity in the system. See section
Verifying the charging capacity of the common DC system on page 22.
 Calculating the rectifier power capacity
The drives which you connect to the AC power line must supply the rectifier power for the
common DC link, and further to the motors. Make sure that the system complies with these
formulas:
P
rec,ave
> P
mot,ave
P
rec,max
> P
mot,max
Use these equations to calculate P
rec,ave
and P
rec,max
:
P
rec,ave
= P
rec,ave1
+ k × (P
rec,ave2
+ P
rec,ave3
+….)
P
rec,max
= P
rec,max1
+ 0.9 × k × (P
rec,max2
+ P
rec,max3
+….)
k Power correction factor for a common DC system. See section Power correction factor (k)
on page 41.
P
mot,ave
Average motoring power of the common DC system during the worst 3 minutes time
window. See section DC link key variables on page 19.
P
mot,max
Maximum motoring power of the common DC system. See section DC link key variables on
page 19.
P
rec, ave
Average rectifier power capacity of the common DC system. See section DC link key
variables on page 19.
P
rec, ave1
Average rectifier power capacity of drive 1. Drive 1 has the highest power rating of the
drives which are connected to AC power line. See section Rectifier power capacity
(Prec,ave and Prec,max) on page 40.
P
rec,ave2
Average rectifier power capacity of drive 2. Drive 2 has the second highest power rating of
the drives which are connected to AC power line. See section Rectifier power capacity
(Prec,ave and Prec,max) on page 40.
P
rec, max
Maximum rectifier power of the common DC system allowed for 10 s. See section DC link
key variables on page 19.
P
rec, max1
Maximum rectifier power capacity of drive 1. See section Rectifier power capacity
(Prec,ave and Prec,max) on page 40.
P
rec,max2
Maximum rectifier power capacity of drive 2. See section Rectifier power capacity
(Prec,ave and Prec,max) on page 40.