Mitsubishi Electric FR-F820-00046 Instruction Manual page 572

 Warning
Output is not shut off when a protective function is activated.
Operation panel
indication
Name Stall prevention (overcurrent)
• When the output current of the inverter increases, the stall prevention (overcurrent) function is activated.
• The following section explains about the stall prevention (overcurrent) function.
During acceleration
Description
During constant-
speed operation
During deceleration
• Check that the Pr.0 Torque boost setting is not too large.
• The Pr.7 Acceleration time and Pr.8 Deceleration time settings may be too short.
• Check that the load is not too heavy.
Check point
• Check for any failures in peripheral devices.
• Check that the Pr.13 Starting frequency is not too large.
• Check that Pr.22 Stall prevention operation level is appropriate.
• Gradually increase or decrease the Pr.0 setting by 1% at a time and check the motor status. (Refer to
527.)
• Set a larger value in Pr.7 and Pr.8. (Refer to
• Reduce the load.
• Try Advanced magnetic flux vector control.
Corrective action
• Change the Pr.14 Load pattern selection setting.
• The stall prevention operation current can be set in Pr.22 Stall prevention operation level. The acceleration/
deceleration time may change. Increase the stall prevention operation level with Pr.22 Stall prevention
operation level, or disable stall prevention with Pr.156 Stall prevention operation selection. (Use Pr.156 to
set either operation continued or not at OL operation.)
Operation panel
indication
Name Stall prevention (overvoltage)
• When the output voltage of the inverter increases, the stall prevention (overvoltage) function is activated.
• The regeneration avoidance function is activated due to excessive regenerative power of the motor. (Refer to
page
• The following section explains the stall prevention (overvoltage) function.
Description
During deceleration
• Check for sudden speed reduction.
Check point
• Check if the regeneration avoidance function (Pr.882 to Pr.886) is being used. (Refer to
Corrective action The deceleration time may change. Increase the deceleration time using Pr.8 Deceleration time.
Operation panel
indication
Name Electronic thermal relay function pre-alarm
Appears if the cumulative value of the electronic thermal O/L relay reaches or exceeds 85% of the preset level
Description of Pr.9 Electronic thermal O/L relay. If the specified value is reached, the protection circuit is activated to shut
off the inverter output.
• Check for large load or sudden acceleration.
Check point
• Check that the Pr.9 setting is appropriate. (Refer to
• Reduce the load and frequency of operation.
Corrective action
• Set an appropriate value in Pr.9. (Refer to
OL
When the inverter output current exceeds the stall prevention level (Pr.22 Stall
prevention operation level, etc.), this function stops the increase in frequency until the
overload current decreases to prevent the inverter from resulting in overcurrent trip.
When the overload current is reduced below stall prevention operation level, this function
increases the frequency again.
When the inverter output current exceeds the stall prevention level (Pr.22 Stall
prevention operation level, etc.), this function decreases the frequency until the
overload current decreases to prevent the inverter from resulting in overcurrent trip.
When the overload current is reduced below stall prevention operation level, this function
increases the frequency up to the set value.
When the inverter output current exceeds the stall prevention level (Pr.22 Stall
prevention operation level, etc.), this function stops the decrease in frequency until the
overload current decreases to prevent the inverter from resulting in overcurrent trip.
When the overload current is reduced below stall prevention operation level, this function
decreases the frequency again.
oL
545.)
If the regenerative power of the motor becomes excessive to exceed the regenerative
power consumption capability, this function stops decreasing the frequency to prevent
overvoltage trip. As soon as the regenerative power has reduced, deceleration resumes.
TH
FR-LU08 indication OL
page 216.)
FR-LU08 indication oL
FR-LU08 indication TH
page 252.)
page 252.)
6.5 Causes and corrective actions
page
page 545.)
6. PROTECTIVE FUNCTIONS
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