Hitachi SJ Series User Manual page 325

Chapter 12
Instantaneous power failure non-stop
Deceleration/Stop ([bA-30] = 01)
A
• This function allows deceleration and stop of the
motor while maintaining the voltage under the
instantaneous power failure non-stop frequency
constant voltage level [bA-32] after the power
supply was shut down during operation.
• If the power supply was shut down during operation,
deceleration starts at the frequency lowered by
deceleration starting width [bA-36] when the
voltage drops to the instantaneous power failure
non-stop function activating voltage [bA-31] or
lower, and then decelerates for the instantaneous
power failure non-stop deceleration time [bA-34].
• In case of regenerative status caused by
deceleration torque during deceleration and if the
internal power supply voltage reaches the
frequency-constant voltage level [bA-32] or higher,
the motor will be at constant speed until the internal
power supply voltage falls below the
overfrequency-constant voltage level [bA-32].
Main Circuit DC PS Voltage (V)
[bA-32]
[bA-31]
Undervoltage Level
Output
Frequency
(Hz)
[IPS] Signal
[bA-36]
[bA-34]
12-13-18
!
• If the frequency-constant voltage level [bA-32] <
Function starting voltage [bA-31], it works by taking
[bA-32] at the same level as [bA-31]. (However, the
set values will not be changed)
• If the frequency-constant voltage level [bA-32] is
lower than the input voltage multiplied by √2, the
constant speed state will be maintained and
deceleration will not take place if the power
recovers while this function is in operation. (Power
should be shut off and turned on again, or [bA-32]
needs to be reset during operation.) The [bA-32]
must be set to a value greater than the input
voltage multiplied by √2.
• This function will not be disabled until the operation
stop will be completed. To recover power and
restart the operation while this function is in
operation, input the stop command (operation
command OFF) and then input the operation
command again after the motor stopped.
• If the instantaneous power failure non-stop
deceleration starting range [bA-34] is too large,
sudden deceleration will cause overcurrent tripping.
• If the value of [bA-36] is too low or the
instantaneous power failure non-stop deceleration
time [bA-34] is too long, insufficient regenerative
force will cause undervoltage tripping.
ON
Time (sec)
Inverter Function
Time (sec)
Time (sec)