Hitachi WJ Series User Manual page 251

Chapter 9
■ Instantaneous power failure non-stop function, mode selection,
"Deceleration-stop ([b050] = 01)"
 When the power is interrupted during operation, once the P-N voltage falls to or below the
"Instantaneous power failure non-stop function, start voltage level [b051]", the output frequency
is reduced to the "Instantaneous power failure non-stop function, start frequency decrement
[b054]", and then deceleration starts for the "Instantaneous power failure non-stop function,
deceleration time [b053]".
 After the power is interrupted during operation, it decelerates to a stop while ensuring that the
P-N voltage does not exceed the "Instantaneous power failure non-stop function, target voltage
level [b052]".
 During deceleration, if the P-N voltage exceeds the "Instantaneous power failure non-stop
function, target voltage level [b052]" due to regeneration, deceleration is stopped and constant
speed operation is performed until the P-N voltage falls below [b052].
Undervoltage
level
 When "Instantaneous power failure non-stop function, target voltage level [b052]" <
!
"Instantaneous power failure non-stop function, start voltage level [b051]", [b052] is regarded as
the same value as [b051] to start operation. (However, this does not change the specified value.)
 Be sure to set [b052] to a value greater than √2 times the input voltage. If [b052] is smaller than
√2 times the input voltage, when the power is restored during the operation of this function, the
motor operation is maintained at constant speed and cannot be decelerated. (Stop command
and changes to frequency command do not work at this time. The power must be turned off and
turned back on, or [b052] must be specified again during operation.)
 If [b054] is too large, it may quickly decelerate upon the operation of this function, resulting in
an overcurrent error. If [b054] is too small or [b053] is too long, an undervoltage error may occur
due to insufficient regenerative power.
P-N voltage (Vdc)
[b052]
[b051]
Output frequency (Hz)
[b054]
[b053]
9-9-18
Inverter Functions
Time
Time