Scr anode-to-cathode resistance – Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control User Manual
Page 201
Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014
201
Commissioning
Chapter 4
Figure 185 - SCR Snubber Circuit Connections
If a device or snubber component is found to be damaged, a detailed replacement
procedure is a located in Chapter 5 – refer to
.
SCR Anode-to-Cathode Resistance
Performing an Anode-to-cathode resistance test verifies the integrity of the SCR.
Unlike the SGCT, the SCR uses the snubber circuit to power the self-powered
gate driver boards. The resistance measurement taken across each SCR should be
consistent; an inconsistent value may indicate a damaged sharing resistor, self-
powered gate driver board or SCR.
Anode
Chillblock
Cathode
Chilblock
Disconnect Points
Rsh-1
Rsn -1
Cs-1
Cs-2
Rsn -2
To Gate Driver Board
TP
Rsh-2
SCR Resistance Measurement
Measured Resistance
SCR Anode-Cathode Resistance
(Heatsink to Heatsink)
k-Ω
(Lowest)
(Highest)
SCR Gate-Cathode Resistance
(Across SCR Phoenix Connector)
Ω
(Lowest)
(Highest)
Snubber Resistance
(Test Point – Heatsink on Left)
Ω
(Lowest)
(Highest)
Snubber Capacitance
(Test Point – White Wire from Snubber
Phoenix connector on Right)
μF
(Lowest)
(Highest)
Sharing Resistance
(Red Wire from Snubber Phoenix
connector – Heatsink on Right)
k-Ω
(Lowest)
(Highest)