Parameter Details
11
11.9 L: Protection Functions
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual 955
Set L2-01 = 3, 4, or 5 [Momentary Power Loss Ope Select = KEB Mode, KEB Stop Mode, or KEB Decel to Stp]
or KEB Ride-Thru 1/2 [H1-xx = 65, 66, 7A, or 7B], to enable the KEB function.
0 : Single Drive KEB Ride-Thru 1
The drive monitors the DC bus voltage and uses regenerative energy from the motor to hold the DC bus voltage at
the level set in L2-11 [KEB DC Bus Voltage Setpoint].
The KEB operation continues and the deceleration rate changes as specified by C1-09 [Fast Stop Time].
Note:
• If the drive detects Uv1 [DC Bus Undervoltage] during KEB operation, decrease the value of C1-09.
• If the drive detects ov [Overvoltage] during KEB operation, increase the value of C1-09.
1 : Single Drive KEB Ride-Thru 2
The drive does KEB operation and automatically calculates the deceleration rate to make sure that the main circuit
electrical energy and main current voltage from motor regenerative energy is equal to L2-11 [DC Bus Vol Setpoint
during KEB].
2 : System KEB Ride-Thru 1
The drive does not monitor the DC bus voltage and decelerates as specified by the KEB deceleration time set in
L2-06.
Set L2-06 to the time necessary to decelerate from the frequency reference to 0 Hz when the drive detects a
momentary power loss. The drive can decelerate and keep constant deceleration rates for more than one drive.
Note:
If you keep constant deceleration rates for more than one drive, it can trigger ov faults. Use the dynamic braking option with System
KEB Ride-Thru 1 to prevent ov faults.
3 : System KEB Ride-Thru 2
The drive monitors the DC bus voltage and decelerates for the deceleration time set in L2-06.
If the DC bus voltage increases, the drive momentarily holds the frequency to prevent ov while deceleration
continues.
Note:
When you cannot use a dynamic braking option, use System KEB Ride-Thru.
■ L2-30: KEB Zero Speed Operation
No.
(Hex.)
Name Description
Default
(Range)
L2-30
(045E)
Expert
KEB Zero Speed
Operation
Sets the operation when the output frequency decreases below the zero level
(DC braking injection starting frequency) during KEB deceleration when
L2-01 = 3 to 5 [Momentary Power Loss Ope Select = KEB Mode, KEB Stop
Mode, or KEB Decel to Stp].
0
(0, 1)
0 : Baseblock
1 : DC/SC Braking
Does DC injection braking and short circuit braking as specified by b2-04 [DC Inject Braking Time at Stop] and
b2-13 [Short Circuit Brake Time @ Stop].
■ L2-31: KEB Start Voltage Offset Level
No.
(Hex.)
Name Description
Default
(Range)
L2-31
(045D)
Expert
KEB Start Voltage
Offset Level
Sets the KEB start voltage offset.
Determined by A1-02
(200 V Class: 0 - 100
V, 400 V Class: 0 -
200 V)
The drive uses this formula to calculate the KEB start voltage:
KEB start voltage = L2-05 [Undervoltage Detect Level (Uv1)] + L2-31
◆ L3: Stall Prevention
L3 parameters set the Stall Prevention function and overvoltage suppression function.
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