Honeywell VFD CORE

CHAPTER 12: DESCRIPTION OF PARAMETER SETTINGS
63-4528—04 198
• DC Brake at Start-up is used for loads that may move before the VFD 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 at stop is used to shorten the stopping time and also to hold a stopped load in position, such as crane or cutting
machine.
• This parameter determines the operation mode when the VFD restarts from a momentary power loss.
• The power connected to the drive may power off momentarily due to many reasons. This function allows the drive to keep
outputting after power is on again after power off and won’t cause drive stops.
• Setting 1: Operation continues after momentary power loss, speed search starts with the Master Frequency reference value
after drive output frequency and motor rotator speed is synchronous. The motor has the characteristics of big inertia and small
obstruction. For example, in the equipment with big inertia wheel, it doesn’t need to wait to execute operation command until
wheel is complete stop after re-start to save time.
• Setting 2: Operation continues after momentary power loss, speed search starts with the master frequency after drive output
frequency and motor rotator speed is synchronous. The motor has the characteristics of small inertia and bigger obstruction.
• If the duration of a power loss is less than this parameter setting, the VFD will resume operation. If it exceeds the Maximum
Allowable Power Loss Time, the VFD output is then turned off (coast stop).
• The selected operation after power loss in Pr.07-05 is only executed when the maximum allowable power loss time is £5
seconds and the VFD displays “LU”.
But if the VFD is powered off due to overload, even if the maximum allowable power loss time is £5 seconds, the operation
mode as set in Pr.07-05 is not executed. In that case it starts up normally
a
07 - 05 Restart after Momentary Power Down
Factory Setting: 0
Settings 0: Stop operation
1: Speed search for last frequency command
2: Speed search for the minimum output frequency
a
07 - 06 Maximum Power Loss Duration
Factory Setting: 2.0
Settings 0.1~20.0 seconds
M33679
OUTPUT
FREQUENCY
RUN / STOP
DC BRAKE TIME
ON
OFF
DC BRAKE TIME
DURING STOPPING
07-04
START-POINT FOR
DC BRAKE TIME
DURING STOPPING
01-09
MINIMUM
OUTPUT
FREQ.
TIME
07-03
07-02