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Rockwell Automation Publication 7000L-UM301F-EN-P - March 2020
Chapter 4
Commissioning
Figure 188 - SCR Gate-to-cathode Test
The resistance value from gate-to-cathode should be between 10 Ω to 20Ω. A
value close to 0 Ω indicates that there is an internal short in the SCR. An
extremely high value indicates that the gate connection in the device has broken.
If a Gate-to-cathode test reveals a damaged SCR, a detailed replacement
procedure is located in Chapter 5 – refer to
Snubber Resistance (SCR 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 chill blocks. For each
device, there is one test point. To verify the resistance, measure the resistance
between the test point and the chill block above.
Disconnect SCR 2-pole
connector from board
Test points for gate to cathode
resistance on 2-pole connector
Disconnect SCR 2-pole
connector from board
Test points for gate to cathode
resistance on 2-pole connector