ABB ACS880-07C, Hardware Manual

Page: 55 / 188

Guidelines for planning the electrical installation 55
Additional data for calculating the rise time and the peak line-to-line voltage
If you need to calculate the actual peak voltage and voltage rise time considering the
actual cable length, proceed as follows:
•
Peak line-to line voltage: Read the relative Û
LL
/ U
N
value from the appropriate diagram
below and multiply it by the nominal supply voltage ( U
N
).
•
Voltage rise time: Read the relative values Û
LL
/ U
N
and (du/dt)/ U
N
from the appropriate
diagram below. Multiply the values by the nominal supply voltage ( U
N
) and substitute
into equation t = 0.8 · Û
LL
/(du/dt).
Additional note for sine filters
Sine filters protect the motor insulation system. Therefore, du/dt filter can be replaced with
a sine filter. The peak phase-to-phase voltage with the sine filter is approximately 1.5 ·
U
N
.
A Drive with du/dt filter
B Drive without du/dt filter
I Motor cable length
Û
LL
/ U
N
Relative peak line-to-line voltage
(du/dt)/U
N
Relative du/dt value
Note : Û
LL
and du/dt values are approximately 20% higher with resistor braking.
Û
LL
/ U
N
l (m)
du/dt
UN
-------------(1/

s)
1.0
2.0
5.0
4.0
3.0
1.5
2.5
3.5
4.5
100 200 300
100 200 300
0.0
0.5
1.0
1.5
2.0
2.5
3.0
l (m)
du/dt
UN
-------------(1/

s)
Û
LL
/ U
N
5.5
A
B