Pet; Power Loss - Allen-Bradley PowerFlex 70 Reference Manual

PET

PET

Power Loss

128
Pulse Elimination Technique – See
Some processes or applications cannot tolerate drive output interruptions caused
by momentary power outages. When AC input line power is interrupted to the
drive, user programming can determine the drive's reaction.
Terms
The following is a definition of terms. Some of these values are drive parameters
and some are not. The description of how these operate is explained below
Term Definition
Vbus The instantaneous DC bus voltage.
Vmem The average DC bus voltage. A measure of the "nominal" bus voltage determined by heavily filtering bus
voltage. Just after the pre-charge relay is closed during the initial power-up bus pre-charge, bus memory
is set equal to bus voltage. Thereafter it is updated by ramping at a very slow rate toward Vbus. The filtered
value ramps at 2.4V DC per minute (for a 480VAC drive). An increase in Vmem is blocked during
deceleration to prevent a false high value due to the bus being pumped up by regeneration. Any change to
Vmem is blocked during inertia ride through.
Vslew The rate of change of Vmem in volts per minute.
Vrecover The threshold for recovery from power loss.
Vtrigger The threshold to detect power loss.
PowerFlex 700
The level is adjustable. The default is the value in the PF700 Bus Level table. If "Pwr Loss Lvl" is selected as
an input function AND energized, Vtrigger is set to Vmem minus [Power Loss Level].
Vopen is normally 60V DC below Vtrigger (in a 480VAC drive). Both Vopen and Vtrigger are limited to a
minimum of Vmin. This is only a factor if [Power Loss Level] is set to a large value.
PowerFlex 70
This is a fixed value.
WARNING:
When using a value of Parameter #186 [Power Loss Level] larger than default, the customer must provide a
minimum line impedance to limit inrush current when the power line recovers. The input impedance
should be equal or greater than the equivalent of a 5% transformer with a VA rating 5 times the drive's
input VA rating.
Vinertia The software regulation reference for Vbus during inertia ride through.
Vclose The threshold to close the pre-charge contactor.
Vopen The threshold to open the pre-charge contactor.
Vmin The minimum value of Vopen.
Voff The bus voltage below which the switching power supply falls out of regulation.
Table 14 PF70 Bus Levels
Class 200/240 VAC
Vslew 1.2V DC
Vrecover Vmem – 30V
Vclose Vmem – 60V
Vtrigger1 Vmem – 60V
Vtrigger2 Vmem – 90V
Vopen Vmem – 90V
Vmin 204V DC
Voff 3 ?
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
Reflected Wave on page 149.
400/480 VAC 600/690 VAC
2.4V DC 3.0V DC
Vmem – 60V Vmem – 75V
Vmem – 120V Vmem – 150V
Vmem – 120V Vmem – 150V
Vmem – 180V Vmem – 225V
Vmem – 180V Vmem – 225V
407V DC 509V DC
300V DC ?