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Replacing sharing resistors, Scr powercages, Replacing sharing resistors scr powercages – 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

75

Component Definition and Maintenance Chapter 3

Figure 54 - Snubber Circuit Assembly (heatpipe model)

Replacing Sharing Resistors

Normally the sharing resistor is part of the snubber resistor assembly. Replacing
the sharing resistor requires also replacing the snubber resistor.

The sharing and snubber resistors are normally located on the backside of the
PowerCage. See the instructions for removing and replacing snubber resistors.

SCR PowerCages

Figure 55

shows the snubber circuit.

Figure 56

shows the physical locations of the

same circuit.

Disconnect the 2-pole plug to the Gate Driver board marked TB1 on the circuit
board. Measure the resistance from the point of the plug that connects to the
point labeled V.SENSE on the Gate Driver board to the anode side heatsink. A
value of 80 kΩ indicates a good sharing resistor.

Rsh

Rsn-2

Cs-1

Rsn-1

Cathode

Anode

Cs-2