Mitsubishi Electric FR-F800 Instruction Manual page 545

Causes and corrective actions
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
Operation panel
indication
Name
Description
Check point
Corrective action
544
PROTECTIVE FUNCTIONS
E.IPF
Instantaneous power failure (Standard models only)
If a power failure occurs for longer than 15 ms (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 100 ms or longer, the fault warning output is not provided, and
the inverter restarts if the start signal is ON upon power restoration. (The inverter continues operating if an
instantaneous power failure is within 15 ms.) 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
420.)
Find the cause of instantaneous power failure occurrence.
• Remedy the instantaneous power failure.
• Prepare a backup power supply for instantaneous power failure.
• Set the function of automatic restart after instantaneous power failure (Pr. 57).
(Refer to page 414, page 420.)
E.UVT
Undervoltage (Standard models only)
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 to about 150 VAC (300 VAC for the 400 V class) or below, this function shuts off the
inverter output.
When a jumper is not connected across P/+ and P1, the undervoltage protective function is activated.
When undervoltage protection is activated, the IPF signal is output. (Refer to
• Check if a high-capacity motor is driven.
• Check if the jumper is connected across terminals P/+ and P1.
• Check the power supply system equipment such as the power supply.
• Do not remove the jumper across terminals P/+ and P1 except when connecting a DC reactor.
• If the problem still persists after taking the above measure, contact your sales representative.
E.ILF
Input phase loss (Standard models only)
When Pr.872 Input phase loss protection selection is enabled ("1") and one of the three-phase power
input is lost, the inverter output is shut off. This protective function is not available when Pr.872 is set to the
initial value (Pr.872 = "0"). (Refer to
Check for a break in the cable for the three-phase power supply input.
• Wire the cables properly.
• Repair a break portion in the cable.
E.OLT
Stall prevention stop
V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
If the output frequency has fallen to 0.5 Hz by stall prevention operation and remains for 3 s, a fault (E.OLT)
appears and the inverter trips. OL appears while stall prevention is being activated.
PM PM PM
During speed control, a fault (E.OLT) appears and the inverter trips if the frequency value converted from the
motor rotation speed drops to 1.5 Hz or lower by stall prevention operation and the output torque exceeds the
Pr.874 OLT level setting (refer to
• Check the motor for the use under overload.
• Check that the Pr.865 and Pr.874 values are correct.
(Check the Pr.22 Stall prevention operation level setting under V/F control and Advanced magnetic flux
vector control.)
• Check if a motor is connected under PM motor control.
• Reduce the load.
• Change the Pr.22, Pr.865, and Pr.874 values. (Check the Pr.22 setting under V/F control and Advanced
magnetic flux vector control.)
• For a test run without connecting a motor, select the PM sensorless vector control test operation.(Refer to
page 144.)
• Also check that the stall prevention (overcurrent) warning (OL) or the stall prevention (overvoltage) warning
(oL) countermeasure is taken.
FR-PU07
FR-PU07
FR-PU07
page 235)
FR-PU07
page 248) and remains there for 3 s.
Inst. Pwr. Loss
page 414, page
Under Voltage
page 414, page 420.)
Input phase loss
Stll Prev STP