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Snubber resistance (scr device) – Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control User Manual

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204

Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014

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

Component Definition and

Maintenance on page 265

.

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