ABB ACQ800 Series Hardware Manual page 57

ACQ800-37 Hardware Manual
Note 8: 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 m (98 foot) and longer cables. The rise
time can be calculated as follows:
Multiply the values of the graph by the supply voltage (U
resistor braking, the Û
3.0
2.5
2.0
1.5
1.0
0.5
0.0
100
With du/dt Filter (R6 and R7i)
Note 9: Sine filters
Sine filters protect the motor insulation system. Therefore, a du/dt filter can be replaced with a sine
filter. The peak phase-to-phase voltage with a sine filter is approximately 1.5 × U
t = 0.8 · Û
and du/dt values are approximately 20% higher.
LL
Û /U
LL N
du/dt
------------ - (1/μs)
U
N
200 300
Cable length (m)
5.5
5.0
du/dt
------------ - (1/μs)
U
4.5
N
4.0
3.5
3.0
2.5
2.0
1.5
1.0
100
Without du/dt Filter (all frame sizes)
/(du/dt). Read Û and du/dt from the diagrams below.
LL LL
). In case of drives with an IGBT supply unit or
N
3.0
2.5
2.0
1.5
1.0
0.5
0.0
100
With du/dt Filter (R8i and nxR8i)
Û /U
LL N
200 300
Cable length (m)
Planning the electrical installation
57
Û /U
LL N
du/dt
------------ - (1/μs)
U
N
200 300
Cable length (m)
.
N