show the typical rate of rise voltage and peak voltages at the motor terminals for both
shielded and unshielded cables in various configurations.
These values are true to steady state operation and at RMS input voltage range of the drive V
line
. When the drive operates in
braking mode, the intermediate DC-link voltage increases by 20%. This effect is similar to increasing the mains voltage by
20%. Consider this voltage increase when performing motor insulation analysis for braking applications.
Motor cable length, m (ft)
dU/dt (kV/
µs)
0
100
(328)
200
(656)
0.50
1.00
1.50
2.00
2.50
3.00
3.50
1
2
3
4
300
(984)
e30bu004.10
1
Unshielded cable with no filter
2
Shielded cable with no filter
3
Unshielded cable with dU/dt filter
4
Shielded cable with dU/dt filter
Illustration 10.17 dU/dt at Motor Terminals for Enclosures E1h/
E3h, 380–500 V
Motor cable length, m (ft)
V
pp
/V
line
0
100
(328)
200
(656)
0.50
1.00
1.50
2.00
2.50
3.00
300
(984)
e30bu005.10
1
2
3
4
1
Unshielded cable with dU/dt filter
2
Shielded cable with dU/dt filter
3
Shielded cable with no filter
4
Unshielded cable with no filter
Illustration 10.18 Peak Voltages at Motor Terminals for
Enclosures E1h/E3h, 380–500 V
Electrical Installation Con...
Design Guide
MG38C202
Danfoss A/S © 01/2018 All rights reserved.
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