Rockwell Automation SD3100 DISTRIB PWR SYS SD3100 DC PWR MODULE - Manual (Page 22)

2-8 SD3100 Power Modules
The two anti-parallel SCR power bridges in a regenerative Power Module control the
direction of motor rotation and the direction of torque, in both forward (motoring) and
reverse (regenerating) directions. The regenerative Power Module allows for
regeneration of power into the AC line under the condition of an overhauling load.
Field Power Module
Operation of the Field Power Module is programmed and controlled in the UDC
module in the AutoMax rack and the PMI Processor in the PMI rack. The firing angle
for each SCR is determined by the field current regulation algorithm executing in the
PMI Processor. The field SCR gating signals are provided by the DC Power
Technology module, under the control of the PMI Processor.
The firing angle for each SCR is synchronized with the AC line feeding it. The PMI
Processor regulates the amount of motor field current by varying the point in the AC
line cycle at which forward conduction begins. The PMI Processor receives the field
current reference from the UDC module in the AutoMax rack. The UDC runs the
application task that provides overall control of the application.
For a full description of the Field Power Module, please refer to instruction manual
S-3060.