Deceleration And Stopping At Power Failure (Nonstop Deceleration At Instantaneous Power Failure) (B050 To B054) - Hitachi NES1-004SB Quick Reference Manual

Chapter 7 Explanation of Functions
7.7.5 Deceleration and stopping at power failure (nonstop deceleration at instantaneous
power failure)
The nonstop deceleration at instantaneous power failure is the function making the inverter decelerate and
stop the motor while maintaining the voltage below the overvoltage level when an instantaneous power
failure occurs during the inverter operation.
You can select three modes with controller deceleration and stop on power loss (b050).
Item
Controller deceleration and stop on
power loss
DC bus voltage trigger level during
power loss
Over-voltage threshold during power
loss (*1)
Deceleration time setting during
power loss
Initial output frequency decrease
during power loss
<1> nonstop deceleration at instantaneous power failure (b050=01)
- The nonstop deceleration at instantaneous power failure is the function making the inverter decelerate
and stop the motor while maintaining the voltage below the overvoltage level (over-voltage threshold
during power loss [b052]) when an instantaneous power failure occurs during the inverter operation.
- If an instantaneous power failure has occurred while the inverter is operating the motor and the output
voltage falls to the DC bus voltage trigger level during power loss (b051) or less, the inverter reduces the
output frequency by the initial output frequency decrease during power loss (b054) once, and then
decelerates the motor for the deceleration time setting during power loss (b053).
- If the voltage increases to an overvoltage level (exceeding the over-voltage threshold during power loss
[b052]) because of regeneration, the inverter enters the LAD stop state until the voltage falls below the
overvoltage level.
Note1:If the over-voltage threshold during power loss (b052) is less than the DC bus voltage trigger level
during power loss (b051), the over-voltage threshold during power loss will be increased to the DC
bus voltage trigger level during power loss when the stop level is applied. (However, the stored
setting will not be changed.)
And, in case b052 is less than the supply voltage (equivalent to rectified DC voltage which is square
root 2 times supply AC voltage), when power recovers while this function is activated, inverter will be
in the LAD stop status and cannot decelerate. (Stop command and frequency change command are
not accepted until deceleration is completed). Be sure to set b052 more than the standard supply
voltage.
Note2:This nonstop deceleration function cannot be canceled until the nonstop deceleration operation is
completed. To restart the inverter operation after power recovery, wait until the inverter stops, enter
a stop command, and then enter an operation command.
Note3:Setting higher initial out put frequency decrease during powerloss (b054) results in over current trip
due to sudden deceleration.
Setting lower b054, orlonger deceleration time during powerloss (b053) results in undervoltage trip
due to less regeneration power.
Voltage across main
circuit terminals P and N
VPN(V)
b052
b051
Undervoltage level
Output frequency
(Hz)
Function code
b050
b051
b052
b053
b054
b054
b053
Data or range of data
00 Disabling the nonstop deceleration function
Enabling the nonstop deceleration function
01
(DEC & STOP)
Enabling the nonstop deceleration function
02
(DC voltage constant control, no restoration)
Enabling the nonstop deceleration function
03 (DC voltage constant control,
Restoration to be done)
0.0 to 400.0 (V) Selectable on 200 V class inverter models
0.0 to 800.0 (V) Selectable on 400 V class inverter models
0.0 to 400.0 (V) Selectable on 200 V class inverter models
0.0 to 800.0 (V) Selectable on 400 V class inverter models
0.01 to 300.0 (s)
0.00 to 10.00 (Hz)
Time
Time
( )
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Description