Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 334)

6-44 Component Definition and Maintenance
7000-UM150I-EN-P – June 2013 7000 “B” Frame
Replacing Sharing Resistor
Normally the sharing resistor is part of the snubber resistor assembly.
Replacement of the sharing resistor will require replacing the
snubber resistor also.
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
The snubber circuit is shown in Figure 6. 31 . Disconnect the 2-pole
plug to the Gate Driver Board that is 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.
Cs-1
Rsh
Rsn-2
Rsn-1
Anode
Cathode
Cs-2
TP
Rsn-2
Rsh
Rsn-1
Anode
To gate driver board
Cs-2
Cathode
Cs-1
Cs-1
Rsh
Rsn-2
Rsn-1
Anode
Cathode
Cs-2
Cs-1
Rsh
Rsn-2
Rsn-1
Anode
Cathode
Cs-2
TP
Rsn-2
Rsh
Rsn-1
Anode
To gate driver board
Cs-2
Cathode
Cs-1
TP
Rsn-2
Rsh
Rsn-1
Anode
To gate driver board
Cs-2
Cathode
Cs-1
Figure 6.31 – Snubber Circuit for SCR Rectifier Module
Sharing Resistors
(cont.)