Delta Electronics VFD-M Pr.32, Momentary Power Loss Operation Selection, Pr.33, Pr.34, Pr.35

Chapter 4 Parameters
Pr.32	Momentary Power Loss Operation Selection

Factory Setting: 00

Settings 00 Operation stops after momentary power loss

01Operation continues after momentary power loss Speed search starts with the Master Frequency reference value

02Operation 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.

4-30 Revision May 2008, ME14, SW V3.04