Operation selection at power failure
and instantaneous power failure
(6) Operation continuation at instantaneous power failure function
constant control) (Pr. 261 = "22")
Deceleration time is automatically adjusted to keep (DC bus) voltage constant in the converter when the inverter
decelerates to a stop. When power is restored during deceleration after an instantaneous power failure,
acceleration is made again up to the set frequency.
When this function is used in combination with the automatic restart after instantaneous power failure operation,
deceleration can be made at a power failure and acceleration can be made again after power restoration. When
power is restored after a stop by deceleration at an instantaneous power failure, automatic restart operation is
performed if automatic restart after instantaneous power failure has been selected (Pr. 57
Setting Pr. 261 = "22" disables the settings of Pr. 262 to Pr. 266.
Pr. 261 = 22
at occurrence of
Deceleration time: automatically adjusted
* Acceleration time depends on Pr. 7 (Pr. 44 ).
(7) Power failure deceleration signal (Y46 signal)
After a power failure stop, inverter cannot start even if power is restored and the start command is given. In this
case, check the power failure deceleration signal (Y46 signal). (at occurrence of input phase loss protection
The Y46 signal is on during deceleration at an instantaneous power failure or during a stop after deceleration at an
instantaneous power failure.
For the Y46 signal, set "46 (forward action)" or "146 (reverse action)" in any of Pr. 190 to Pr. 196 (output terminal
function selection) to assign the function.
Stop selection function is disabled while inverter decelerates due to a power failure, even though stop selection (Pr.250) is set.
When Pr. 30 Regenerative function selection = "2" (FR-HC, MT-HC, FR-CV is used), the power failure deceleration function is
When the (output frequency - Pr. 262) at undervoltage or power failure occurrence is negative, the calculation result is regarded
as 0Hz. (DC injection brake operation is performed without deceleration).
During a stop or trip, the power failure stop selection is not performed.
Y46 signal turns on when undervoltage occurs even when the motor is not decelerating at an instantaneous power failure. For
this reason, Y46 signal outputs instantly at powering off, which is not a fault.
When power failure deceleration stop function is selected, undervoltage protection (E.UVT), instantaneous power failure
protection (E.IPF), and input phase loss protection (E.ILF) do not function.
Changing the terminal assignment using Pr. 190 to Pr. 196 (output terminal function selection) may affect the other terminals. Please
make setting after confirming the function of each terminal.
Even if the power failure stop function is valid, some loads may cause the inverter to trip and the motor to coast.
The motor will coast if enough regenerative energy is given from the motor.
Parameters referred to
Pr. 12 DC injection brake operation voltage
Pr. 20 Acceleration/deceleration reference frequency, Pr. 21 Acceleration/deceleration time increments
Pr. 30 Regenerative function selection
Pr. 57 Restart coasting time
Pr. 190 to Pr. 196 (output terminal function selection)
Pr. 872 Input phase loss protection selection
When power is restored during
deceleration at occurrence of
Refer to page 100
Refer to page 102
Refer to page 136
Refer to page 116
Refer to page 146
Pr.261 = 22, Pr.57
During power failure
at occurrence of
(with DC bus voltage
When used with automatic restart
after instantaneous power failure
Reset time + Pr.57
Refer to page 90