Mitsubishi Electric 800 Series Instruction Manual page 529

(A) Application parameters
NOTE
• If the automatic restart after instantaneous power failure is
selected (Pr.57 Restart coasting time  "9999") while the power
failure time deceleration stop function is set enabled (Pr.261 = "1,
11, or 21"), the power failure time deceleration stop function is
disabled.
• When the power failure time deceleration stop function is enabled
(Pr.261 = "1, 11 or 21"), the inverter will not start even if the
power is turned ON or inverter reset is performed with the start
signal (STF/STR) ON. Turn OFF the start signal once and then
ON again to make a start.
Continuous operation function at instantaneous power failure (Pr.261
="2, 12, 22")
• The motor re-accelerates to the set frequency if the power restores during the deceleration to stop.
• Combining with the automatic restart after instantaneous power failure function enables a power failure time deceleration
stop and re-acceleration at a power restoration.
If the power is restored after stoppage by a power failure, a restart operation is performed when automatic restart after
instantaneous power failure (Pr.57  "9999") is selected.
When power is restored during
Pr.261 = 2
deceleration at occurrence of
power failure
Power
supply
Output
frequency
During deceleration
at occurrence of
power failure
Y46
∗1 Acceleration time depends on Pr.7 (Pr.44 ).
Undervoltage avoidance function (Pr.261 = "11, 12" Pr.294)
• If "11, 12" is set to Pr.261, the deceleration time is adjusted (shortened) to prevent an undervoltage from occurring during
deceleration at occurrence of power failure.
• Adjust the downward frequency slope and the response level using Pr.294 UV avoidance voltage gain. Setting a large
value improves the response to the bus voltage.
NOTE
• The undervoltage avoidance function is invalid under torque control by Real sensorless vector control. When "11 (12)" is set
to Pr.261, operation is the same as when "1 (2) is set to Pr.261.
528
PARAMETERS
IPF
Output
frequency
Reacceleration ∗1
Time
Power supply
STF
Y46
Pr.261 = 2, Pr.57 9999
During power failure
Power
supply
During deceleration
at occurrence of
power failure
Y46
ON
Not started as inverter
is stopped due to power
failure
OFF
ON
ON
When used with automatic restart
after instantaneous power failure
Automatic restart
after instantaneous
power failure
Time
Reset time + Pr.57
Output
frequency
Time