Delta Electronics VFD-M Series, User Manual

Page: 65 / 173

Chapter 4 Parameters
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4-30 Revision May 2008, ME14, SW V3.04
Pr.32
Momentary Power Loss Operation Selection
Factory Setting: 00
Settings 00 Operation stops after momentary power loss
01 Operation continues after momentary power loss Speed search starts with
the Master Frequency reference value
02 Operation continues after momentary power loss Speed search starts with
the min frequency
Pr.33
Maximum Allowable Power Loss Time
Unit: 0.1sec
Settings 0.3 to 5.0 sec Factory Setting: 2.0 sec
After a power loss, the AC drive will resume operation only if the power loss duration is shorter
than the time defined by Pr.33. If the Maximum Allowable Power Loss Time is exceeded, the
AC drive output is then turned off.
Pr.34
Base-Block Time for Speed Search
Unit: 0.1sec
Settings 0.3 to 5.0 sec Factory Setting: 0.5 sec
When a momentary power loss is detected, the AC drive will stop its output and will wait during
a specified time interval called Base Block (entered in Pr.34) before resuming operation.
Setting of this parameter should make the residual output voltage due to regeneration almost
zero, before the drive resumes operation.
This parameter also determines the search time when performing external Base-Block and
Fault Reset (Pr.72).
Pr.35
Maximum Current Level for Speed Search
Unit: 1%
Settings 30 to 200% Factory Setting: 150
Following a power failure, the AC drive will start its speed search operation only if the output
current is greater than the value determined by Pr.35. When the output current is less than that
of Pr.35, the AC drive output frequency is at a “speed synchronization point” and will
accelerate or decelerate back to the operating frequency at which it was running prior to the
power failure.