Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - ForGe Control (PanelView 550) User Manual

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Rockwell Automation Publication 7000-UM151E-EN-P - January 2013

Appendix C Snubber Testing

Easy access from the anode-to-cathode is available by going from heatsink-to-
heatsink as shown in the diagram below:

Figure 257 - Anode-to-cathode test

A good SCR and circuit should read between 22 and 24 kΩ.

An SCR that has failed from anode-to-cathode will commonly produce a
resistance value of 0 for a shorted device or

∞

Ω for an opened device. Unlike the

SGCT, it is highly irregular for an SCR to have a partially shorted device. If an
SCR is found to be out of tolerance, refer to

for detailed instructions on how to replace the SCR

assembly.

Resistance value between 2 heatsinks
is Anode-to-Cathode resistance