Fuji Electric frenic mini series, User Manual

Page: 176 / 269

9.2 Details of Function Codes
9-19
Chap. 9
FUNCTI
ON C
O
DE
S
Trip immediately (F14 = 0)
If an instantaneous power failure occurs when the inverter is in Running mode so that the
inverter detects undervoltage of the DC link circuit, then the inverter immediately shuts
down its outputs 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 of power (F14 = 1)
If an instantaneous power failure occurs when the inverter is in Running mode so that the
inverter detects undervoltage of the DC link circuit, then the inverter immediately shuts
down its outputs 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.
This setting is used when you run/stop the motor by turning the inverter power on/off with
any run command being ON. Turning off the controller power with the power switch will
not cause the inverter to transfer to Alarm mode or trip.
Restart at the frequency at which the power failure occurred (F14 = 4)
If an instantaneous power failure occurs when the inverter is in Running mode so that the
inverter detects undervoltage of the DC link circuit, then the inverter saves the current
output frequency.
When the power is recovered with any run command being ON, the inverter will restart at
the saved frequency. During the instantaneous power failure, if the motor speed slows
down, the current limiter facility 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) on the
following page for details.
To synchronize the output frequency and motor speed, the instantaneous 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 is coasting to a stop because of the
instantaneous power failure.
Restart at the starting frequency (F14 = 5)
If an instantaneous power failure occurs when the inverter is in Running mode so that the
inverter detects undervoltage of the DC link circuit, then the inverter immediately shuts
down its outputs. After the power is recovered, entry of any run command will restart the
inverter at the frequency specified by function code F23. Refer to the figure (F14 = 5) on
the following page for details.
This setting is optimal for operations in which the motor speed quickly slows down to 0
rpm due to its heavy load with a very small moment of inertia if the motor coasts to a stop
because of the instantaneous power failure.
• There is a 0.5 second delay from detection of the undervoltage until the motor
is restarted. This delay is due to the time required for the residual electricity
(magnetic flux) in the motor to erase. Therefore, the motor will restart with a
0.5-second delay after the power is recovered, even if the instantaneous power
failure period is shorter than 0.5 second.
• When an instantaneous power failure occurs, the power supply voltage for
external circuitry (such as relay circuits) that controls the inverter may also
drop to the extent that run commands are disabled.
To avoid this happening, have the system wait 2 seconds before the issue of run
commands. If any run command is issued within 2 seconds, however, the
inverter will restart. If it is after 2 seconds, the inverter will start at the starting
frequency preset by the related function codes. Your power system should be
configured so that it is able to issue any run command within 2 seconds, or so
that it features a mechanical latch relay mechanism that ensures the safety of
the system in the event of an instantaneous power failure.