2.9 L: Protection Functions
372 YASKAWA TOEPYAIGA5002A GA500 DRIVE PROGRAMMING
KEB frequency level = Output frequency before power loss × (1 - (L2-02)/ (L2-06))
Figure 2.109 Kinetic Energy Backup Decel Time
■ L2-07: Kinetic Energy Backup Accel Time
No.
(Hex.)
Name Description
Default
(Range)
L2-07
(048B)
Expert
Kinetic Energy Backup
Accel Time
Sets the acceleration time to return the frequency to the frequency reference before a power loss after
canceling KEB operation.
0.0 s
(0.0 - 6000.0 s)
Set this parameter to 0.0 to disable the function. The drive uses the acceleration time in C1-01, C1-03, C1-05, and C1-
07 to accelerate again after KEB operation completes.
■ L2-08: Frequency Gain at KEB Start
No.
(Hex.)
Name Description
Default
(Range)
L2-08
(048C)
Expert
Frequency Gain at KEB
Start
Sets the quantity of output frequency reduction used when KEB operation starts as a percentage of
the motor rated slip before starting KEB operation.
100%
(0 - 300%)
Decreases the output frequency in steps to quickly set the motor to a regenerative condition. Use this formula to
calculate the value:
Output frequency reduction = Motor rated slip before KEB operation × (L2-08/100 ) × 2
■ L2-09: KEB Minimum Frequency Level
No.
(Hex.)
Name Description
Default
(Range)
L2-09
(048D)
Expert
KEB Minimum Frequency
Level
Sets the quantity of output frequency reduction used as a percentage of E2-02 [Motor Rated Slip]
when KEB operation starts.
20%
(0 - 100%)
These conditions set the quantity of decrease:
• Motor rated slip × (L2-09/100)
• The larger value between the value calculated with L2-08 and the value calculated with L2-09
■ L2-10: Minimum KEB Time
No.
(Hex.)
Name Description
Default
(Range)
L2-10
(048E)
Expert
Minimum KEB Time
Sets the minimum length of time to operate the KEB after the drive detects a momentary power loss.
50 ms
(0 - 25500 ms)
When you return power while KEB is operating, the drive continues KEB operation until the time set in L2-10 is
expired. When the DC bus voltage is less than the level of L2-05 [Undervoltage Detection Lvl (Uv1)] in one of these
conditions, KEB operation continues until the time set in L2-10 is expired:
• L2-01 = 3 [Power Loss Ride Through Select = Kinetic Energy Backup: L2-02]
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