Fuji Electric FRENIC-HVAC User Manual page 399

• When the motor speed decreases significantly during coast-to-stop (with the current limiter
activated):
• Secure more than 0.1 second after turning ON the "Switch to commercial power"
signal before turning ON a run command.
• Secure more than 0.2 second of an overlapping period with both the "Switch to
commercial power" signal and run command being ON.
• If an alarm has been issued or BX has been ON when the motor drive source is
switched from the commercial power to the inverter, the inverter will not be
started at the commercial power frequency and will remain OFF. After the alarm
has been reset or BX turned OFF, operation at the frequency of the commercial
power will not be continued, and the inverter will be started at the ordinary
starting frequency.
If you wish to switch the motor drive source from the commercial line to the
inverter, be sure to turn BX OFF before the "Switch to commercial power" signal
is turned OFF.
• When switching the motor drive source from the inverter to commercial power,
adjust the inverter's reference frequency at or slightly higher than that of the
commercial power frequency beforehand, taking into consideration the motor
speed down during the coast-to-stop period produced by switching.
• Note that when the motor drive source is switched from the inverter to the
commercial power, a high inrush current will be generated, because the phase of
the commercial power usually does not match the motor speed at the switching.
Make sure that the power supply and all the peripheral equipment are capable of
withstanding this inrush current.
• If you have enabled "Restart after momentary power failure" (F14 = 3, 4, or 5),
keep BX ON during commercial power driven operation to prevent the inverter
from restarting after a momentary power failure.
6.3 Details of Function Codes
6-89