Delta Electronics VFD-S manual Momentary Power Loss Operation Selection, 8-05, 8-06, 8-07

Chapter 5 ParametersVFD-S Series

DC Brake during Start-up is used for loads that may move before AC drive starts, such as fans and pumps. These loads may also be moving in the wrong direction. Under such circumstances, DC Brake can be executed to hold the load in position before applying a forward motion.

DC Brake during stopping is used to decrease stopping time and also to hold a stopped load in position. For high inertial loads, a dynamic brake resistor may be needed for quick decelerations.

8-04Momentary Power Loss Operation Selection

				Factory Setting: d0
	Settings	d0	Operation stops after momentary power loss
		d1	Operation continues after momentary power loss, speed search
			starts with the Master Frequency reference value
		d2	Operation continues after momentary power loss, speed search
			starts with the minimum frequency
8-05	Maximum Allowable Power Loss Time			Unit: 0.1
	Settings	d0.3 to d5.0Sec		Factory Setting: d2.0

During a power loss, if the power loss time is less than the time defined by this parameter, the AC drive will resume operation. If the Maximum Allowable Power Loss Time is exceeded, the AC drive output is then turned off.

8-06	Base Block Speed Search		Unit: 0.1
	Settings	d0.3 to d5.0Sec	Factory Setting: d0.5

When a momentary power loss is detected, the AC drive turns off for a specified time interval determined by Pr.8-06 before resuming operation. This time interval is called Base-Block. This parameter should be set to a value where the residual output voltage is nearly zero, before the drive resumes operation.

This parameter also determines the searching time when performing external Base-Block and fault reset.

8-07	Current Limit for Speed Search		Unit: 1
	Settings	d30 to d200％	Factory Setting: d150

Revision August 2008, SE09, SW V2.61 5-59