Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 191)

4-32 Commissioning
7000-UM150I-EN-P – June 2013 7000 “B” Frame
Damage to a sharing resistor is easily detected if the SGCT is
replaced and the anode to cathode resistance remains abnormal. If
the resistor is found to be out of tolerance, refer to Chapter 6 –
Component Definition and Maintenance for detailed instructions on
how to replace the snubber/sharing resistor assembly.
Snubber Resistance (SGCT Device)
Access to the snubber resistor is not required to test the resistance.
The snubber circuit test point is located within the PowerCage under
the heatsinks. For each device, there is one test point. To verify the
resistance, measure the resistance between the test point and the
heatsink above.
Measure resistance
between heatsink
and test point.
Snubber test point
Figure 4.5 – Snubber Resistor Test
Refer to Table 4.A to determine the appropriate snubber resistance
value for the current rating of the SGCT used.
If the resistor is found to be out of tolerance, refer to Chapter 6 –
Component Definition and Maintenance for detailed instructions on
how to replace the snubber resistor assembly.