Planning the electrical installation
55
Additional data for calculating the rise time and the peak line-to-line voltage
The peak line-to-line voltage at the motor terminals generated by the drive as well as 
the voltage rise time depend on the cable length. The requirements for the motor 
insulation system given in the table are “worst case” requirements covering 
installations with 30 meter and longer cables. 
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. A factory-installed sine filter is 
available for the cabinet-installed units. The peak phase-to-phase voltage with the 
sine filter is approximately 1.5 × U
N
. 
Additional note common mode filters
Common mode filter is available as a plus code option (+E208).
l Motor cable length 
A Graph for calculating the rise time of units with du/dt filter
B Graph for calculating the rise time of units without du/dt filter
Û
LL
/U
N
du/dt
U
N
-------------(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
U
N
-------------(1/s)
Û
LL
/U
N
5.5
l (m)
A
B