FujiFilm Frenic-Mini Instruction Manual page 94

This setting is optimal for operations in which the motor speed quickly slows down
to 0 rpm due to the heavy load with a very small moment of inertia if the motor
coasts to a stop because of the instantaneous power failure.
If you select restart after instantaneous power failure (F14 = 4 or 5), the inverter will
automatically restart running the motor when the power is recovered.
The machine should be so designed that human body and peripheral equipment
safety is ensured even after automatic restarting.
Otherwise an accident could occur.
F15, F16
Frequency Limiter (Peak and Bottom)
Frequency limiter F15 limits the peak of output frequency. Frequency limiter F16
maintains the output frequency at the bottom even if the set frequency is lower
than the bottom. Refer to the figure below.
• 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 drop suffi-
ciently. Therefore, even if the instantaneous power failure period is
shorter than 0.5 second, a delay of at least 0.5 second is required
for the motor to restart.
• When an instantaneous power failure occurs, the power supply volt-
age for external circuitry (such as relay circuits) that controls the
inverter may also drop to the extent that run commands are disabled.
Therefore, have the system wait 2 seconds before the issue of run
commands. If any run command is issued within 2 seconds, how-
ever, the inverter will restart. If it is after 2 seconds, the inverter will
start at the starting frequency preset by the related function codes.
The external circuitry should be configured so that it is able to issue
any run command within 2 seconds, or so that it features a mechani-
cal latch relay mechanism that ensures the safety of the system in
the event of an instantaneous power failure.
• If a coast-to-stop command (BX) is issued during the time from the
detection of an instantaneous power failure to repowering, the
inverter exits from the state of waiting for restarting, and enters Run-
ning mode. If any run command is issued, the inverter will start at the
starting frequency preset.
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