Mitsubishi Electric FR-A701 Instrucion Manual page 156

Operation Panel
E.OLT
Indication
Name
Stall prevention
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.)
Operation Panel
E.GF
Indication
Name Output side earth (ground) fault overcurrent
This function stops the inverter output if an earth (ground) fault overcurrent flows due to an earth
Description
(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
E.LF
Indication
Name
Output phase loss
This function stops the inverter output if one of the three phases (U, V, W) on the inverter's output side
Description
(load side) is lost.
· Check the wiring (Check that the motor is normal.)
Check point
· Check that the capacity of the motor used is not smaller than that of the inverter.
· Wire the cables properly.
Corrective action
· Check the Pr. 251 Output phase loss protection selection setting.
Operation Panel
E.OHT
Indication
Name External thermal relay operation
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.
Description
Functions when "7" (OH signal) is set in any of Pr. 178 to Pr. 189 (input terminal function selection).
When the initial value (without OH signal assigned) is set, this protective function does not function.
· Check for motor overheating.
Check point
· Check that the value of 7 (OH signal) is set correctly in any of Pr. 178 to Pr. 189 (input terminal function selection).
· Reduce the load and operating duty.
Corrective action
· Even if the relay contacts are reset automatically, the inverter will not restart unless it is reset.
Operation Panel
E.PTC
Indication
Name
PTC thermistor operation
Stops the inverter output when the motor overheat status is detected for 10s or more by the external
PTC thermistor input connected to the terminal AU.
Description This fault functions when "63" is set in Pr. 184 AU terminal function selection and AU/PTC switchover
switch is set in PTC side. When the initial value (Pr. 184 = "4") is set, this protective function does not
function.
· Check the connection between the PTC thermistor switch and thermal protector.
· Check the motor for operation under overload.
Check point
· Is valid setting ( = 63) selected in Pr. 184 AU terminal function selection ? (Refer to chapter 4 of
instruction manual (applied).)
Corrective action Reduce the load weight.
Causes and corrective actions
FR-PU04
Stll Prev STP ( OL shown during stall
prevention operation)
FR-PU07
the instruction manual (applied) .)
FR-PU04
Ground Fault
FR-PU07
FR-PU04
E. LF
FR-PU07
FR-PU04
OH Fault
FR-PU07
FR-PU04 Fault 14
FR-PU07 PTC activated
5
the
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