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Operation panel
E.OV2
indication
Name
Regenerative overvoltage trip during constant speed
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the specified value,
Description
the protective circuit is activated to stop the inverter output. The circuit may also be activated by a surge voltage
produced in the power supply system.
Check for sudden load change.
Check point
Check that the setting of Pr. 22 Stall prevention operation level is not too small.
Check if the stall prevention operation is frequently activated in an application with a large load inertia.
Keep load stable.
Use regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886). (Refer to page 262)
Corrective action
Use the brake resistor, brake unit or power regeneration common converter (FR-CV) as required.
Set the Pr.22 Stall prevention operation level correctly.
Set Pr.154 Voltage reduction selection during stall prevention operation = "11".
Operation panel
E.OV3
indication
Name
Regenerative overvoltage trip during deceleration or stop
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the specified value,
Description
the protective circuit is activated to stop the inverter output. The circuit may also be activated by a surge voltage
produced in the power supply system.
Check for sudden speed reduction.
Check point
Check if the stall prevention operation is frequently activated in an application with a large load inertia.
Increase the deceleration time. (Set the deceleration time which matches the moment of inertia of the load)
Make the brake cycle longer.
Corrective action
Use regeneration avoidance function (Pr. 882, Pr. 883, Pr. 885, Pr. 886). (Refer to page 262)
Use the brake resistor, brake unit or power regeneration common converter (FR-CV) as required.
Set Pr.154 Voltage reduction selection during stall prevention operation = "11".
Operation panel
E.THT
indication
Name
Inverter overload trip (electronic thermal O/L relay function)
If the temperature of the output transistor element exceeds the protection level under the condition that a current not
Description
less than the rated inverter current flows and overcurrent trip does not occur (170% or less), the electronic thermal
relay activates to stop the inverter output. (Overload capacity 120% 60s, 150% 0.5s)
Check that acceleration/deceleration time is not too short.
Check that Pr. 0 Torque boost setting is not too large (small). (V/F control)
Check point
Check that Pr. 14 Load pattern selection setting is appropriate for the load pattern of the using machine. (V/F control)
Check the motor for use under overload.
Check for too high surrounding air temperature.
Increase acceleration/deceleration time.
Adjust the Pr. 0 Torque boost setting. (V/F control)
Corrective action
Set the Pr. 14 Load pattern selection setting according to the load pattern of the using machine. (V/F control)
Reduce the load weight.
Set the surrounding air temperature to within the specifications.
Operation panel
E.THM
indication
Name
Motor overload trip(electronic thermal O/L relay function)
The electronic thermal relay function in the inverter detects motor overheat due to overload or reduced cooling
capability during constant-speed operation, and pre-alarm (TH display) is output when the integrated value reaches
85% of the Pr. 9 Electronic thermal O/L relay setting, and the protection circuit is activated to stop the inverter output
Description
when the integrated value reaches the specified value. When running a special motor such as a multi-pole motor or
multiple motors, provide a thermal relay on the inverter output side since such motor(s) cannot be protected by the
electronic thermal relay function.
Check the motor for use under overload.
Check that the setting of Pr. 71 Applied motor for motor selection is correct. (V/F control, General-purpose magnetic
Check point
flux vector control) (Refer to page 123)
Check that stall prevention operation setting is correct.
Reduce the load weight.
For a constant-torque motor, set the constant-torque motor in Pr. 71 Applied motor. (V/F control, General-purpose
Corrective action
magnetic flux vector control)
Check that stall prevention operation setting is correct. (Refer to page 96)
Resetting the inverter initializes the internal accumulated heat value of the electronic thermal relay function.
Causes and corrective actions
FR-PU04
Stedy Spd OV
FR-PU07
FR-PU04
OV During Dec
FR-PU07
FR-PU04
Inv. Overload
FR-PU07
FR-PU04
Motor Ovrload
FR-PU07
5
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