5-22
- Trip immediately (F14 = 0)
If a momentary power failure occurs when the inverter is in Running mode so that
the inverter detects undervoltage of the DC link bus, then the inverter immediately
stops its output and displays the undervoltage alarm
lu
on the LED monitor. The
motor will coast to a stop and the inverter will not restart automatically.
- Trip after recovery from power failure (F14 = 1)
If a momentary power failure occurs when the inverter is in Running mode, causing
the inverter to detect undervoltage of the DC link bus, the inverter immediately stops
its output without transferring to Alarm mode or displaying the undervoltage alarm
lu
. The motor will coast to a stop. When the power is recovered, the inverter will
enter Alarm mode for undervoltage with displaying the alarm
lu
. The motor will be
still coasting.
- Restart at the frequency at which the power failure occurred (F14 = 4)
If a momentary power failure occurs when the inverter is in Running mode so that
the inverter detects undervoltage of the DC link bus, then the inverter saves the
current output frequency and stops its output to make the motor to coast to a stop.
When the power is recovered with any run command being on, the inverter will re-
start at the saved frequency.
During the momentary power failure, if the motor speed slows down, the current
limiter function of the inverter will be activated and automatically lower the output
frequency. Upon synchronization of the output frequency and motor speed, the
inverter accelerates up to the previous output frequency. Refer to the figure (F14 =
4) given below for details.
To synchronize the output frequency and motor speed, however, the momentary
overcurrent limiter (H12 = 1) should be enabled.
This setting is optimal for operations in which the motor speed rarely slows down
due to the heavy moment of inertia of its load even if the motor coasts to a stop
because of the momentary power failure.
- Restart at the starting frequency (F14 = 5)
If a momentary power failure occurs when the inverter is in Running mode so that
the inverter detects undervoltage of the DC link bus, then the inverter immediately
stops its output. After the power is recovered, entry of any run command will restart
the inverter at the frequency specified by function code F23.
To Next Page
Loading...
