Parameter Details
11
11.9 L: Protection Functions
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual 953
Note:
If the low voltage detection level is near the lower limit value of L2-05, the drive will detect Uv1 during KEB Ride-Thru operation. Do
not set the value too low when you use the KEB Ride-Thru function.
■ L2-06: Kinetic Energy Backup Decel Time
No.
(Hex.)
Name Description
Default
(Range)
L2-06
(048A)
Expert
Kinetic Energy
Backup Decel Time
Sets the deceleration time during KEB operation used to decrease the
maximum output frequency to 0.
0.0 s
(0.0 to 6000.0 s)
Set L2-29 = 2 or 3 [Kinetic Energy Backup Method = System KEB Ride-Thru 1 or System KEB Ride-Thru 2] to
enable this function. When L2-29 = 1, 2 , 3 [Kinetic Energy Backup Method = Single Drive KEB Ride-Thru 2,
System KEB Ride-Thru 1, System KEB Ride-Thru 2] and you do KEB Auto-Tuning, the drive will automatically
set this value.
Sets the deceleration time necessary to decelerate from the frequency reference to 0 Hz when the drive detects a
momentary power loss. If a Uv1 [DC Bus Undervoltage] fault occurs during KEB operation, decrease the
deceleration time. If an ov [Overvoltage] fault occurs, increase the deceleration time.
• L2-06 = 0
The drive automatically decreases C1-09 [Fast Stop Time] to the base value to keep the DC bus voltage above
the low voltage detection level. The drive ignores L2-02 [Momentary Power Loss Ride-Thru Time] in this
condition.
• L2-06 ≠ 0
As shown in Figure 11.133, the frequency reference decelerates to the KEB frequency level as specified by the
deceleration rate set in L2-06 and then returns to the initial frequency reference as specified by C1-01
[Acceleration Time 1]. The drive uses the setting value of the KEB frequency rate as shown in the this formula
to set the KEB frequency level:
KEB frequency level = Output frequency before power loss × (1 - (L2-02)/ (L2-06))
Figure 11.133 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 to 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%)
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