Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 274)

Commissioning 4-69
7000 “C” Frame 7000L-UM300I-EN-P – Juen 2013
Line Terminal Resistance Measurements
Measuring the resistance between the drive line cable terminals will
quickly identify if there is interwiring between the 0

, +20

, and -20

bridges in the isolation transformer.
2U
3U
4U
3V
4V
4W
3W
2V
2W
U
V
W
2U
3U
4U
3V
4V
4W
3W
2V
2W
U
V
W
Figure 4.24 – 18-pulse Terminals
There are low resistances between phases through a transformer
winding and a high resistance between transformer windings.
Therefore, the expected resistance measurements are listed in the
table below:
Terminal Measurement Points Expected Resistance
2U  2V  2W Approximately 0 Ω
3U  3V  3W Approximately 0 Ω
4U  4V  4W Approximately 0 Ω
2 ?  3 ?  4 ? Approximately ∞ Ω
If the measurement results are not as described above, the interwiring
between the isolation transformer and drive needs to be re-inspected.