Parameter Details
12
12.9 L: Protection Functions
YASKAWA SIEPC71061753C GA500 Technical Manual 703
When power returns in the time set in L2-02, the drive will restart. If power does not return in the time set in L2-
02, the drive will detect Uv1.
The drive momentarily turns OFF its output after a power loss. If the power returns in the time set to L2-02, the
drive will do Speed Search and try to continue operation.
If the DC bus voltage is less than or equal to the Uv1 detection level for the time set in L2-02, the drive will detect
Uv1 and output a fault signal.
Note:
• The necessary time for the drive to restart after power returns is different for different drive capacities.
• The upper limit of the possible momentary power loss Ride-Thru time is different for different drive models.
2 : Enabled while CPU Power Active
This setting will enable for the time set in L2-02 [Power Loss Ride Through Time] or until the CPU is inactive.
When the CPU is inactive, b1-17 [Run Command at Power Up] sets operation at power up.
When power returns and the drive control circuit has power, the drive will restart. This will not trigger Uv1.
When there is a momentary power loss, the drive output will turn OFF. If the power returns and the drive control
circuit has power, the drive will do Speed Search and try to continue operation. This will not trigger a Uv1. This
function lets the drive lose power for longer than when L2-01 = 1.
3 : Kinetic Energy Backup: L2-02
If power does not return in the time set in L2-02, the drive will detect Uv1.
If the drive detects momentary power loss, the drive will use regenerative energy from the motor and ramp to
stop. When you return power in the time set in L2-02, the drive will accelerate to the frequency reference value
that the drive used before the power loss. If you do not return power in the time set to L2-02, the drive will detect
Uv1 and the drive output will turn OFF. L2-29 [Kinetic Energy Backup Method] sets the type of KEB operation.
4 : Kinetic Energy Backup: CPU Power
When power returns and the drive control circuit has power, the drive will restart.
The drive decelerates using regenerative energy from the motor until the power returns and then restarts when a
momentary power loss is detected. When power is restored during deceleration, the drive accelerates the motor
again to the frequency reference value used before the power loss. If the motor comes to a stop before the power
returns, the drive loses control power and the drive output shuts off. A Uv1 is not triggered when power is restored
while power to the CPU in the drive is maintained. L2-29 sets the type of KEB operation.
5 : Kinetic Energy Backup: DecelStop
When power returns, the drive will continue to decelerate until the motor fully stops.
If the drive detects momentary power loss, the drive will use regenerative energy from the motor and ramp to
stop. When you return power to the drive, the drive will continue to decelerate until the motor comes to a full
stop. After you return power, the drive will ramp to stop in the set deceleration time. L2-29 sets the type of KEB
operation.
Note:
When you set L2-01, make sure that you know these items:
• You can use a Momentary Power Loss Unit on models 2001 to 2042 and 4001 to 4023 for a longer momentary power loss ride through
time. A Momentary Power Loss Unit makes it possible to continue operation of the drive after a maximum of 2 seconds of power loss.
• When you set L2-01 = 1 to 4, keep the magnetic contactor on the drive input side ON and keep the control signal while the drive does
KEB operation.
• When L2-01 = 1 to 5, Uv [DC Bus Undervoltage] will flash on the keypad while the drive is attempting to recover from a momentary
power loss. The drive will not output a fault signal at this time.
• When you use a magnetic contactor between the motor and the drive, keep the magnetic contactor closed while the drive does KEB
operation or tries to restart with Speed Search.
• Keep the Run command active during KEB operation. The drive cannot accelerate back to the frequency reference when the power
returns.
• When L2-01 = 3 to 5, if the control power supply voltage is less than the CPU operation level during KEB Ride-Thru, it will trigger
Uv1.
■ L2-02: Power Loss Ride Through Time
No.
(Hex.)
Name Description
Default
(Range)
L2-02
(0486)
Power Loss Ride Through
Time
Sets the length of time that the drive will wait before it tries to restart if the DC bus voltage is less
than L2-05 [Undervoltage Detection Lvl (Uv1)] after a momentary power loss.
Determined by o2-04, C6-
01
(0.0 - 25.5 s)
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