Deceleration And Stopping At Power Failure - Hitachi SJ700B Series Instruction Manual

4.2.91 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
Proportional gain setting for nonstop operation at
momentary power failure
Integral time setting for nonstop operation at
momentary power failure
<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.
- To use this function, remove the J51 connector cables from terminals R0 and T0, connect the main circuit
terminals P and R0 to each other, and connect the main circuit terminals N and T0 to each other. Use
0.75 mm2 or heavier wires for the connections.
- 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.
Chapter 4 Explanation of Functions
b050: Controller deceleration and stop on power loss
b051: DC bus voltage trigger level during power loss
b052: Over-voltage threshold during power loss
b053: Deceleration time setting during power loss
b054: Initial output frequency decrease during power
loss Integral time setting for nonstop operation at
momentary power failure
b055: Proportional gain setting for nonstop operation
at momentary power failure
b056: Integral time setting for nonstop operation at
momentary power failure
Function code Data or range of data
b050
b051 0.0 to 999.9/1000. (V)
b052 0.0 to 999.9/1000. (V)
0.01 to 99.99/100.0 to
b053 999.9/1000. to 3600.
b054 0.00 to 10.00 (Hz)
b055 0.00 to 2.55
0.0 to 9.999 /
b056
10.00 to 65.53(s)
4 - 83
Related code
Description
Disabling the nonstop
00
deceleration function
Enabling the nonstop
01
deceleration function
02
03
(s)
Proportional gain at DC voltage
constant control(Only when
"02" or "03" is specified for
b050)
Integral time at DC voltage
constant control(Only when
"02" or "03" is specified for
b050)