Mitsubishi FR-A721-11K Instruction Manual page 158

Operation Panel
E.IPF
Indication
Name
Instantaneous power failure
If a power failure occurs for longer than 15ms (this also applies to inverter input shut-off), the
instantaneous power failure protective function is activated to trip the inverter in order to prevent the
control circuit from malfunctioning. If a power failure persists for longer than 100ms, the fault output is
not provided, and the inverter restarts if the start signal is on upon power restoration. (The inverter
Description continues operating if an instantaneous power failure is within 15ms.) In some operating status (load
magnitude, acceleration/deceleration time setting, etc.), overcurrent or other protection may be
activated upon power restoration.
When instantaneous power failure protection is activated, the IPF signal is output. (Refer to Chapter 4 of
the Instruction Manual (Applied))
Check point
Find the cause of instantaneous power failure occurrence.
Remedy the instantaneous power failure.
Prepare a backup power supply for instantaneous power failure.
Corrective action
Set the function of automatic restart after instantaneous power failure (Pr. 57). (Refer to Chapter 4 of
Operation Panel
E.UVT
Indication
Name Undervoltage
If the power supply voltage of the inverter decreases, the control circuit will not perform normal functions.
In addition, the motor torque will be insufficient and/or heat generation will increase. To prevent this, if
the power supply voltage decreases below about 150VAC (300VAC for the 400V class), this function
Description
stops the inverter output.
When undervoltage protection is activated, the IPF signal is output. (Refer to Chapter 4 of
Instruction Manual (Applied))
Check point
Check for start of large-capacity motor.
Check the power supply system equipment such as the power supply.
Corrective action
If the problem still persists after taking the above measure, please contact your sales representative.
Operation Panel
E.ILF
Indication
Name
Input phase loss
This fault is output when function valid setting (= 1) is set in Pr. 872 Input phase loss protection selection
and one phase of the three phase power input is lost. (If the input power voltage is less than 100VAC,
Description
the inverter may detect an input phase loss (E.ILF).) (Refer to Chapter 4 of
(Applied).)
Check point
Check for a break in the cable for the three-phase power supply input.
Wire the cables properly.
Corrective action
Repair a break portion in the cable.
Check the Pr. 872 Input phase loss protection selection setting.
Operation Panel
E.OLT
Indication
Name
Stall prevention stop
If the frequency has fallen to 0.5Hz by stall prevention operation and remains for 3s, a fault (E.OLT)
appears and trips the inverter. OL appears while stall prevention is being activated.
When speed control is performed by Real sensorless vector control or vector control, a fault (E.OLT) is
Description
displayed and the inverter output is stopped if frequency drops to the Pr. 865 Low speed detection (initial
value is 1.5Hz) setting by torque limit operation and the output torque exceeds Pr. 874 OLT level setting
(initial value is 150%) setting and remains for more than 3s.
Check the motor for use under overload. (Refer to Chapter 4 of
Check point
Check that the Pr. 865 Low speed detection and Pr. 874 OLT level setting values are correct. (Check the
Pr. 22 Stall prevention operation level setting if V/F control is exercised.)
Reduce the load weight.
Corrective action
Change the Pr. 22 Stall prevention operation level, Pr. 865 Low speed detection and Pr. 874 OLT level
setting values. (Check the Pr. 22 Stall prevention operation level setting if V/F control is exercised.)
the Instruction Manual (Applied) .)
Causes and corrective actions
FR-PU04
Inst. Pwr. Loss
FR-PU07
FR-PU04
Under Voltage
FR-PU07
FR-PU04 Fault 14
FR-PU07 Input phase loss
FR-PU04
Stll Prev STP ( OL shown during stall
prevention operation)
FR-PU07
the Instruction Manual (Applied) .)
the
the Instruction Manual
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