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

Page 84

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84

Rockwell Automation Publication 7000-UM202B-EN-P - June 2014

Chapter 3

Component Definition and Maintenance

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 heat sinks. For each
device, there is one test point. To verify the resistance, measure the resistance
between the test point and the heat sink above.

Figure 77 - Snubber resistance test

Refer to

Table 2 on page 79

to determine the appropriate snubber resistance value

for the current rating of the SCR used.

If the resistor is found to be out of tolerance, refer to

page 72

for the snubber

resistor assembly replacement procedure.

Heatsink

Heatsink

To Gate Driver Board

Heatsink

Heatsink

Snubber
Resistor

Snubber
Capacitor

Sharing Resistor

Test Point

Resistance value between test point and
heat sink to its left is snubber resistance