Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) Commissioning - ForGe Control - Manual (Page 39)

Rockwell Automation Publication 7000-IN012B-EN-P - June 2014 39
Commissioning the Drive Chapter 4
SGCT and Snubber Circuit With all power semiconductors or thyristors, the SGCT requires a snubber
circuit. The snubber circuit for the SGCT consists of a snubber resistor in series
with a snubber capacitor.
Figure 18 shows the snubber circuit. Figure 28 shows the physical locations of the
same circuit. Measure the resistance across two adjacent heat sinks. A value
between 60 kΩ and 75 kΩ indicates a good sharing resistor.
Figure 18 - Snubber Circuit for SGCT module
Figure 19 - Snubber Circuit for SGCT module (with SPS board)
Rsn-2
Rsn-1
Anode
Cs-1
Rsh
Cs-2
Snubber
Resistor
Test Cathode
Heatsink Heatsink
Rsn-2
Rsn-1
Anode
Cs-1
Rsh
Cs-2 Snubber
Resistor
Test
Cathode
Heatsink Heatsink
SPS Board
J1-1
J1-2