The drive detects momentary power loss when the drive DC bus voltage is less than the value set in L2-05 [Undervoltage Detection Lvl (Uv1)].
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- Disable
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A momentary power loss triggers Uv1 [DC Bus Undervoltage].
If you do not restore power in 15 ms, a Uv1 is triggered and the drive shuts off the output. The motor coasts to stop.
- 1
- Enabled
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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 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:
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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.
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The necessary time for the drive to restart after power returns is different for different drive capacities.
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The upper limit of the possible momentary power loss Ride-Thru time is different for different drive models.
- 2
- Enabled while CPU Power Active
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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.
Note:
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.
- 3
- Kinetic Energy Backup: L2-02
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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
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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
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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.