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Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control User Manual

Page 240

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4-66

Commissioning

7000A-UM150F-EN-P – June 2013

7000 “A” Frame

Input Phasing Check

There are 3 voltage test points on the Line Signal Conditioning
Board that will allow you to look at each voltage connection
individually.


These test points are labeled as follows:

Table 4.C – SCBL Test Points and Associated Voltage Signals

Test Point

Description

Isolation Transformer:

Secondary Phasing and Bridge

Phase Relationship with

respect to Vab1-Out (2U)

Vab1-Out

2U

Master

Vbc1-Out

2V

Master

-120°

Vca1-Out

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 Vab1-Out 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.





1) Ref A: 5 Volt 2 ms
2) Ref B: 5 Volt 2 ms

V

BCX-OUT

V

ABX-OUT


For 60 Hz systems, 360° = 16.7 ms.

For 50 Hz systems, 360° = 20 ms.