“B” Group: Fine-Tuning Functions
Configur
ing Dr
iv
e
P
a
ra
meters
3–42
Controlled Deceleration at Power Loss
– When enabled, this feature permits the inverter to
control final motor deceleration upon loss of inverter input power. First, you must make a
wiring change to the inverter. See
“Optional Controlled Decel and Alarm at Power Loss” on
page 4–4
for complete instructions including wiring and signal timing diagrams for using the
controlled deceleration at power loss
feature.
After making the wiring change, use function B050 to enable the feature. Use B051 to deter-
mine the point at which a decaying DC bus voltage will trigger the controlled deceleration. Use
parameter B054 to specify an initial step-wise deceleration at power loss, and B053 to specify
the duration of the linear deceleration.
During the controlled deceleration the inverter itself acts as a load to decelerate the motor. With
either a high-inertia load or a short deceleration time (or both), it is possible that the inverter
impedance will not be low enough to continue linear deceleration and avoid an over-voltage
condition on the DC bus. Use parameter B052 to specify a threshold for the over-voltage. In
this case, the inverter pauses deceleration (runs at constant speed). When the DC bus decays
again below the threshold, linear deceleration resumes. The pause/resume process will repeat as
necessary until the DC bus energy is depleted (under-voltage condition occurs).
The case when setting B052 is lower than the inverter supply voltage has special consider-
ations:
• If B052 Over-voltage Threshold During Power Loss is less than B051 DC Bus Voltage
Trigger Level During Power Loss, the over-voltage threshold during power loss will be
increased to the DC bus voltage trigger level with the stop level is applied. However, the
parameter setting will not be changed.
• When B052 is less than the supply voltage (the rectified DC voltage or the AC voltage times
square root of two), when power recovers the inverter will be in the LAD-stop state and
cannot decelerate. (The Stop Command and frequency change command are ignored until
deceleration is complete.) be sure to set B052 higher than the standard supply voltage.
• A non-stop deceleration function cannot be canceled until it is complete. To restart the
inverter operations after power recovery, wait until the inverter stops. Then enter a Stop
Command and then an operation command (FW, RV).
• Setting a higher value for B054 Initial Output Frequency Decrease During Power Loss
results in an over-current trip due to sudden deceleration. Setting a lower value for B054 or
larger value for B053 Deceleration Time Setting During Power Loss results in under-voltage
trip due to reduced regenerative energy.
Non-stop deceleration at instantaneous power failure (B050=01) has these characteristics:
• 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.
B045
Torque limit LADSTOP enable
OFF
00
Disable
00
00
00
✘ ✔
Temporarily stops accel/decel ramps
during torque limit. Available for
SLV, 0 Hz domain, or vector control
with feedback mode
ON
0 1
Enable
✘ ✔
B046
Reverse Run protection enable
OFF
00
Disable
00
00
00
✘ ✔
Prohibits reverse motor rotation
ON
0 1
Enable
Func.
Code
Name/
Description
Keypad
Range and Settings
Defaults
Run
Mode
Edit
Lo Hi
SRW
OPE
FEF2
FE2
(EU)
FUF2
FU2
(USA)
FF2
F2
(Jpn)
