149
Causes and corrective actions
Operation Panel
Indication
E.OLT
FR-PU04
FR-PU07
Stll Prev STP ( OL shown during stall
prevention operation)
Name
Stall prevention
Description
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
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 point
· Check the motor for use under overload.
(Refer to chapter 4 of
the instruction manual (applied) .)
· 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.)
Corrective action
· Reduce the load weight.
· 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
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
FR-PU07
E. LF
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.
Corrective action
· Wire the cables properly.
· Check the
Pr. 251
Output phase loss protection selection
setting.
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.
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 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.
Operation Panel
Indication
E.PTC
FR-PU04
Fault 14
FR-PU07
PTC activated
Name
PTC thermistor operation
Description
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.
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 point
· Check the connection between the PTC thermistor switch and thermal protector.
· Check the motor for operation under overload.
· Is valid setting ( = 63) selected in
Pr. 184 AU terminal function selection
?
(Refer to chapter 4 of
the
instruction manual (applied).)
Corrective action
Reduce the load weight.
Summary of Contents for FR-A741-11K
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