Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control - Manual (Page 67)

Rockwell Automation Publication 7000A-UM200C-EN-P - June 2014 67
Component Definition and Maintenance Chapter 3
SGCT and Snubber Circuit
As with all power semi-conductors or thyristors, the SGCT must have a snubber
circuit. The snubber circuit for the SGCT is comprised of a snubber resistor in
series with a snubber capacitor.
The snubber circuit is shown in Figure 48 . The physical locators of the same
circuit are shown in Figure 56 . Measure the resistance across two adjacent
heatsinks. A value between 60 kΩ and 75 kΩ indicates a good sharing resistor.
Figure 48 - Snubber Circuit for SGCT module
Figure 49 - 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