Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 210)

4-56 Commissioning
7000A-RM001A-EN-P – January 2011 7000 “A” Frame
Input Phasing Check
There are 3 voltage test points on the ACB Board that will allow you
to look at each voltage level individually.
These test points are labeled as follows:
Table 4.C – ACB Test Points and Associated Voltage Signals
Test Point
Description
Isolation Transformer:
Secondary Phasing and Bridge
Phase Relationship with
respect to Vab1-Out (2U)
V2uv 2U Master 0°
V2vw 2V Master -120°
V2wu 2W Master -240°
All of these test points can be measured to either the Analog Ground
on the board or the TE ground in the low voltage section. You can
use V2uv as your reference (trigger on this waveform) and verify all
the other test points using the table above. It is easier to use zero
crossings on your oscilloscope as the reference points when checking
the phase shifts.
Essentially, you are verifying the following relationships:
1.
V and W in each bridge should be lagging U by 120° and 240°,
respectively.
Figure 4.16 – CH1 is 2Vuv, CH2 is 2Vvw, CH3 is 2Vwu
For 60 Hz systems, 360° = 16.7 ms.
For 50 Hz systems, 360° = 20 ms.