Rockwell Automation 20A PowerFlex 70EC/700VC - Manual (Page 26)

22 Bus Regulation
The bus voltage regulation setpoint is determined from bus memory (a means to
average DC bus over a period of time). The following tables and figure describe the
operation.
If [Bus Reg Mode x] is set to “Dynamic Brak”
The Dynamic Brake Regulator is enabled. In “Dynamic Brak” mode the Bus
Voltage Regulator is turned off. The “DB Turn On” and turn off curves apply. For
example, with a DC Bus Memory at 684V DC, the Dynamic Brake Regulator will
turn on at 750V DC and turn back off at 742V DC.
If [Bus Reg Mode x] is set to “Both-Frq 1st”
Both regulators are enabled, and the operating point of the Bus Voltage Regulator is
lower than that of the Dynamic Brake Regulator. The Bus Voltage Regulator
setpoint follows the “Bus Reg Curve 2” below a DC Bus Memory of 650V DC and
follows the “DB Turn Off” curve above a DC Bus Memory of 650V DC (
Table C ).
The Dynamic Brake Regulator follows the “DB Turn On” and turn off curves. For
example, with a DC Bus Memory at 684V DC, the Bus Voltage Regulator setpoint
is 742V DC and the Dynamic Brake Regulator will turn on at 750V DC and back
off at 742V DC.
If [Bus Reg Mode x] is set to “Adjust Freq”
The Bus Voltage Regulator is enabled. The Bus Voltage Regulator setpoint follows
“Bus Reg Curve 1” below a DC Bus Memory of 650V DC and follows the “DB
Turn On” above a DC Bus Memory of 650V DC (
Table C ). For example, with a DC
Bus Memory at 684V DC, the adjust frequency setpoint is 750V DC.
Voltage Class DC Bus Memory DB On Setpoint DB Off Setpoint
240 < 342V DC 375V DC On – 4V DC
> 342V DC Memory + 33V DC
480 < 685V DC 750V DC On – 8V DC
> 685V DC Memory + 65V DC
600 < 856V DC 937V DC On – 10V DC
> 856V DC Memory + 81V DC
600/690V
PowerFlex 700
Frames 5 & 6 Only < 983V DC 1076V DC On – 11V DC
> 983V DC Memory + 93V DC
320 360 460 484 528 576
453
509
650
685
750
815
880
AC Volts
DC Volts
DB Turn On
DB Turn Off
Bus Memory
Bus Reg Curve #2 Bus Reg Curve #1