Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 97)

Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013 97
Detail Drive Configuration and Operation Chapter 1
Ride Through Operation
An incoming power loss to the drive is detected by a 22% drop in bus voltage or a
bus voltage that drops below the under voltage level. The return of incoming
power is detected by an 11% rise in bus voltage and a bus voltage level greater
than the undervoltage level set in parameter 409 [Line Undervolts]. If the
undervoltage condition is selected as a fault, parameter 393
[BusUndervoltCnfg], then the drive will not restart if the incoming power
returns. Upon sensing a power loss the drive can be configured to coast, continue
operation or change to flux only operation. (See Ride Through Configuration
below).
In cases where the precharge control is independent or external to the drive
(firmware) the ride through function can still be used to stop PWM operation
saving controller power and restart operation after the return of power is sensed.
In this case ride through sequence will not be directly coordinated with the
precharge operation. For external precharge hardware functionality is provided
so that the user may provide coordinated operation.
Ride Through Configuration
The drive's response to a power disturbance can be selected in parameter 406
[Power Loss Mode].
Settings for Parameter 406 [Power Loss Mode]:
Coast (default): The coast mode stops power to the motor (PWM disabled) and
the motor coasts until power returns or a fault occurs. At the time when the
motor PWM is disabled the precharge device bypass (where controlled by the
drive) is also opened. Then the precharge logic is reset so that the drive starts
another precharge cycle. After the incoming power returns and the precharge
cycle has completed, the drive restarts normal operation.
Continue: Disables the ride through function and will attempt to continue
running if the incoming power is disrupted. If the power returns before the drive
has shut down, the precharge device will be bypassed and a large inrush current
may occur. In this case, drive damage is likely if the inrush current is large.
408 Power Loss Level
Sets the bus voltage level at which ride-through begins and modulation ends. When bus voltage falls
below this level, the drive prepares for an automatic reset. Enter a percentage of the bus voltage
derived from the high voltage setting for the voltage class
For example: on a 400-480V drive,
Units:
Default:
Min/Max: %
22.1
15/95 x 16-bit
Integer
0.221 480Vac 2
Ч Ч
150Vdc =
0 Coast
1 Reserved
2 Continue
3 Reserved
4 Reserved
5 Flux Only