Delta Electronics VFD-EL manual Momentary Power Loss Operation Selection, 08.05

Chapter 4 Parameters

DC Brake during Start-up is used for loads that may move before the AC drive starts, such as fans and pumps. Under such circumstances, DC Brake can be used to hold the load in position before setting it in motion.

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

08.04Momentary Power Loss Operation Selection

		Factory Setting: 0
Settings	0	Operation stops (coast to stop) after momentary power loss.
	1	Operation continues after momentary power loss, speed search
		starts with the Master Frequency reference value.
	2	Operation continues after momentary power loss, speed search
		starts with the minimum frequency.

This parameter determines the operation mode when the AC motor drive restarts from a momentary power loss.

08.05	Maximum Allowable Power Loss Time		Unit: 0.1
	Settings	0.1 to 5.0 sec	Factory Setting: 2.0

If the duration of a power loss is less than this parameter setting, the AC motor drive will resume operation. If it exceeds the Maximum Allowable Power Loss Time, the AC motor drive output is then turned off (coast stop).

The selected operation after power loss in Pr.08.04 is only executed when the maximum allowable power loss time is ≤5 seconds and the AC motor drive displays “Lu”.

But if the AC motor drive is powered off due to overload, even if the maximum allowable power loss time is ≤5 seconds, the operation mode as set in Pr.08.04 is not executed. In that case it starts up normally.

08.06Base Block Speed Search

Factory Setting: 1

Settings 0 Disable

1Speed search starts with last frequency command

2Speed search starts with minimum output frequency (Pr.01.05)

This parameter determines the AC motor drive restart method after External Base Block is enabled.

4-78 Revision August 2008, 2ELE, V1.02