Mitsubishi Electric FR-A800, Instruction Manual

Page: 765 / 1042

Parameters (A) Application parameters
FR-A800 5 - 585
Automatic adjustment of deceleration time (Pr. 261 = "21, 22", Pr. 294, Pr. 668)
●
When "21, 22" is set to Pr. 261, the deceleration time is automatically adjusted to keep (DC bus)
voltage constant in the converter when the motor decelerates to a stop at a power failure. Setting
of Pr. 262 to Pr. 266 is not required.
●
If a phenomenon such as motor vibration occurs during operation of the deceleration time
automatic adjustment function, adjust the response level by setting the Pr. 668 "Power failure stop
frequency gain". Increasing the setting improves the response to change in the bus voltage.
However, the output frequency may become unstable.
●
If setting Pr. 294 "UV avoidance voltage gain" lower does not suppress the vibration, set Pr. 668
lower.
Deceleration stop by the power failure stop external signal (X48)
●
By turning OFF X48 signal, the power failure time deceleration-to-stop function is activated. This
function is used, for example, when an external power failure detection circuit is installed.
●
To use the power failure time deceleration-to-stop function for the separated converter type, use
X48 signal. Connect the terminal to which PWF signal of the converter unit is assigned and the
terminal to which X48 signal of the inverter is assigned.
●
In the initial setting, X48 signal is used with the normally closed (NC contact) input specification.
Use Pr. 606 "Power failure stop external signal input selection" to change the specification to the
normally open (NO contact) input.
●
To use the X48 signal, set "48" in any of Pr. 178 to Pr. 189 (Input terminal function selection) to
assign the function to an input terminal.
During deceleration at occurrence of power failure signal (Y46)
●
After deceleration by a power failure, the inverter is not restarted even though the start command
is input. Check the during deceleration at occurrence of power failure signal (Y46) at a power
failure. (for example, when input phase loss protection (E.ILF) occurs)
●
The Y46 signal is turned ON during deceleration at occurrence of power failure and in a stop status
after deceleration at a power failure.
●
For the Y46 signal, assign the function by setting "46 (forward action)" or "146 (reverse action)" in
any of Pr. 190 to Pr. 196 (Output terminal function selection).
I003071E
Fig. 5-294: Automatic adjustment of deceleration time
STF
Y46
Pr. 261 = 21
During deceleration at occurrence of power failure
Deceleration time : Automatic adjustment
During stop at occurrence
of power failure
Output
frequency
Power
supply
Time
Turn OFF STF once to make acceleration again