Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 189)

4-30 Commissioning
7000-UM150I-EN-P – June 2013 7000 “B” Frame
SGCT Testing
The following steps outline how to verify SGCT semiconductors and
all associated snubber components. A quick reference to the
expected resistance and capacitance values as well as a simple
schematic diagram is located in the table below.
Table 4.A – SGCT Snubber Circuit Resistance and Capacitance Values
SGCT Rating Sharing Resistor  Snubber Resistor Snubber Capacitor
1500 Amp 80 kΩ 7 Ω (PWMR)  0.2 µf
1500 Amp 80 kΩ 7.3 Ω (Inverter)  0.2 µf
800 Amp 80 kΩ 10 Ω 0.1 µf
400 Amp 80 kΩ 15 Ω (PWMR) 0.1 µf
400 Amp 80 kΩ 17.5 Ω (Inverter) 0.1 µf
 2300V drives will not have a sharing resistor on devices.
Figure 4.3 – SGCT Snubber Circuit Connections
SGCT Resistance Measurement
Measured Resistance
Inverter Rectifier (PWM only)
SGCT Anode-Cathode Resistance
(Heatsink to heatsink)
__________ – __________ kΩ
(Lowest) (Highest)
__________ – __________ kΩ
(Lowest) (Highest)
Snubber Resistance
(Test Point – Heatsink above)
__________ – __________ Ω
(Lowest) (Highest)
__________ – __________ Ω
(Lowest) (Highest)
Snubber Capacitance
(Test Point – Heatsink on Right)
__________ – __________ µF
(Lowest) (Highest)
__________ – __________ µF
(Lowest) (Highest)
If a device or snubber component is found to be damaged, it must be
replaced using the detailed procedures in Component Definition and
Maintenance.