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Causes and corrective actions
Operation Panel
Indication
E.OLT
FR-PU04
FR-PU07
Stll Prev STP
Name
Stall prevention stop
Description
If the frequency has fallen to 0.5Hz(1.5Hz under IPM motor control) 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.
Check point
· Check the motor for use under overload. ( Refer to Chapter 4 of the Instruction Manual (Applied).)
· Check that a motor is connected during IPM motor control. (IPM motor control)
Corrective action
· Reduce the load weight.
· Check the connection of the IPM motor. (IPM motor control)
· Set the IPM motor test operation. ( Refer to Chapter 4 of the Instruction Manual (Applied))
Operation Panel
Indication
E.SOT
FR-PU04
Fault 14
FR-PU07
Motor step out
Name
Loss of synchronism detection
Description
Stops the output when the operation is not synchronized. (This function is only available under IPM
motor control.)
Check point
· Check that the IPM motor is not driven overloaded.
· Check if a start command is given to the inverter while the IPM motor is coasting.
· Check if a motor other than the IPM motor (MM-EFS series or MM-EF series) is driven.
Corrective action
· Set the acceleration time longer.
· Reduce the load.
· If the inverter restarts during coasting, set Pr.57 Restart coasting time ≠ "9999," and select the
automatic restart after instantaneous power failure.
· Drive the IPM motor (MM-EFS series or MM-EF series).
Operation Panel
Indication
E.GF
FR-PU04
FR-PU07
Ground Fault
Name
Output side earth (ground) fault overcurrent
Description
This function stops the inverter output if an earth (ground) fault overcurrent flows due to an earth
(ground) fault that occurred on the inverter's output (load) side.
Check point
Check for an earth (ground) fault in the motor and connection cable.
Corrective action
Remedy the earth (ground) fault portion.
Operation Panel
Indication
E.LF
FR-PU04
E. LF
FR-PU07
Name
Output phase loss
Description
This function stops the inverter output if one of the three phases (U, V, W) on the inverter's output side
(load side) is lost.
Check point
· Check the wiring (Check that the motor is normal.)
· Check that the capacity of the motor used is not smaller than that of the inverter.
· Check if a start command is given to the inverter while the motor is coasting.
Corrective action
· Wire the cables properly.
· Choose inverter and motor capacities that match.
· Input a start command after the motor stops. Alternatively, use automatic restart after instantaneous
power failure/flying start function. ( Refer to Chapter 4 of the Instruction Manual (Applied)
Operation Panel
Indication
E.OHT
FR-PU04
FR-PU07
OH Fault
Name
External thermal relay operation
Description
If the external thermal relay provided for motor overheat protection, or the internally mounted
temperature relay in the motor, etc. switches ON (contacts open), the inverter output is stopped.
This function is available when "7" (OH signal) is set to any of Pr. 178 to Pr. 189 (input terminal function
selection).
When the initial value (without OH signal assigned) is set, this protective function is not available.
Check point
· Check for motor overheating.
· Check that the value of 7 (OH signal) is set correctly in any of Pr. 178 to Pr. 189 (input terminal function
selection).
Corrective action
· Reduce the load and operating duty.
· Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.
IPM
IPM
IPM