11.9 L: Protection Functions
954 YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
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 when KEB operation
starts as a percentage of the motor rated slip.
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 L2-10is
expired. When the DC bus voltage is less than the level of L2-05 [Undervoltage Detect Level (Uv1)] in one of
these conditions, KEB operation continues until the time set in L2-10 is expired:
• L2-01 = 3 [Momentary Power Loss Ope Select = KEB Mode].
• L2-01 = 4 [KEB Stop Mode]
• L2-01 = 5 [KEB Decel to Stp].
• KEB Ride-Thru 1/2 [H1-xx = 65, 66, 7A, or 7B] is input into the drive.
When you input KEB Ride-Thru, KEB operation continues after the time set in L2-10 is expired. When you
cancel KEB Ride-Thru, the motor accelerates again. When you do not input KEB Ride-Thru during the time set in
L2-10, the drive accelerates to the frequency reference that the drive had before power loss in the applicable
acceleration time.
When L2-01 = 3, 4, or 5, and the DC bus voltage is a minimum of the value of L2-11 [DC Bus Vol Setpoint during
KEB], the drive accelerates again after the time set in L2-10 is expired. If the DC bus voltage is less than the L2-
11 value, KEB operation continues after the time set in L2-10 is expired.
Note:
• When L2-01 = 0, 1, or 2 [Disabled, Enabled, or Enabled when CPU is Running], increase the value of L2-10. Set L2-10 to cancel
KEB operation if the KEB Ride-Thru is not input
• Set this parameter to 0 to disable the function.
■ L2-11: KEB DC Bus Voltage Setpoint
No.
(Hex.)
Name Description
Default
(Range)
L2-11
(0461)
Expert
KEB DC Bus Voltage
Setpoint
Sets the target value that controls the DC bus voltage to a constant level in
Single Drive KEB Ride-Thru 2. Sets the DC bus voltage level that
completes the KEB operation for all other KEB methods.
Determined by E1-01
(Determined by E1-
01)
■ L2-29: Kinetic Energy Backup Method
No.
(Hex.)
Name Description
Default
(Range)
L2-29
(0475)
Expert
Kinetic Energy
Backup Method
Sets the KEB function operation mode.
0
(0 - 3)
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