Hitachi SJ Series, User Manual

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12-14-4
Chapter 12 Inverter Function
When instantaneous power failure/under-voltage
occurs [bb-24]=01
Ex. 1: Power recovery within Allowable
instantaneous power failure time [bb-25]
• If a power failure has occurred so that the power to
the inverter's control power supply terminals
(R0,T0) is lost, and then the inverter is restarted, it
is considered as power-on and the inverter will
operate in accordance with the restart after reset
[bb-41].
• Even if the power to control power supply terminals
(R0, T0) is lost, it will take time until the internal
power supply is completely lost.
• Trip after instantaneous power
failure/under-voltage can be switched between
"enabled" and "disabled" by using [bb-27] Selection
of instantaneous power failure/under-voltage trip
during stopping. This will prevent the occurrence of
an error during stopping. If the error is prevented,
the output terminal [AL] will not turn on.
t0: Instantaneous power failure time
t1: Allowable instantaneous power failure time [bb-25]
t2: Retry wait time [bb-26]
Ex. 2: Power recovery after Allowable instantaneous
power failure time [bb-25]
• In a system where the power to control power
supply terminals (R0, T0) gradually decreases, it is
possible to cause a trip when Allowable
instantaneous power failure time has elapsed.
• To make the power to control power supply
terminals (R0, T0) last as much as possible by the
inverter alone during an instantaneous power
failure, remove the J51 connector cables from
terminals R0 and T0, and connect a cable from P
on the main circuit terminal block to R0, and N on
the main circuit terminal block to T0. Use 0.75 mm
2
or heavier wires for the connections.
Item Parameter Data Description
Selection of instantaneous power
failure/under-voltage retry [bb-24] 01 Performs frequency matching restart.
Allowable instantaneous power
failure time [bb-25] 0.3~25.0(s) Restarts the motor if it is within the
allowable time.
Retry wait time after
instantaneous power
failure/under-voltage [bb-26] 0.3~100.0(s) Sets the wait time after the operation
command.
!
t1
T0
Free-running
Power
supply
Inverter
output
Motor speed
[bb-42]
t0 t2
t1
Free-running
Power supply
Inverter
output
Motor speed
[bb-42]
Restarting with frequency
matching