Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) - Manual (Page 131)

Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013 121
Troubleshooting Chapter 9
Current Loop Power Supply The current loop gate driver (CLGD) boards receive power from two sources:
1. The snubber circuit (while the SCR power modules are active).
2. The current loop power supply, which maintains a pre-charge level of
power during periods when the SCR power modules are inactive (this
allows SCR gating while the snubber circuit is being charged).
Figure 49 - Current Loop Power Supply
The current loop power supply provides a current of 50 AC to each SCR power
module phase assembly. If this current is not detected and fed back to the
interface boards, stop maneuvers will not function (and an Alarm will be
generated).
To Interface Board
Phase A
Phase B
Phase C