Mitsubishi Electric FR-F720P-0.75K to 110K Instruction Manual page 323

Causes and corrective actions
(2) Warning
When the protective function is activated, the output is not shut off.
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
312
OL
Stall prevention (overcurrent)
When the output current of the inverter exceeds the stall prevention operation level (Pr.
22 Stall prevention operation level, etc.), this function stops the increase in frequency until
During
the overload current decreases to prevent the inverter from resulting in overcurrent trip.
acceleration
When the overload current has decreased below stall prevention operation level, this
function increases the frequency again.
When the output current of the inverter exceeds the stall prevention operation level (Pr.
During
22 Stall prevention operation level, etc.), this function lowers the frequency until the
constant
overload current decreases to prevent overcurrent trip. When the overload current has
speed
decreased below stall prevention operation level, this function increases the frequency
operation
up to the set value.
When the output current of the inverter exceeds the stall prevention operation level (Pr.
22 Stall prevention operation level, etc.), this function stops the decrease in frequency until
During
the overload current decreases to prevent the inverter from resulting in overcurrent trip.
deceleration
When the overload current has decreased below stall prevention operation level, this
function decreases the frequency again.
· Check that the Pr. 0 Torque boost setting is not too large.(V/F control)
· Check that the Pr. 7 Acceleration time and Pr. 8 Deceleration time settings are not too small.
· Check that the load is not too heavy.
· Are there any failure in peripheral devices?
· Check that the Pr. 13 Starting frequency is not too large.(V/F control, Simple magnetic flux vector
control)
· Check that the Pr. 22 Stall prevention operation level is appropriate.
· Check if the operation was performed without connecting a motor under IPM motor control.
· Increase or decrease the Pr. 0 Torque boost value by 1% and check the motor status. (V/F control) (Refer to
page 87.)
· Set a larger value in Pr. 7 Acceleration time and Pr. 8 Deceleration time. (Refer to page 109.)
· Reduce the load weight. Try Simple magnetic flux vector control (Pr. 80).
· Check the peripheral devices
· Adjust the Pr.13 setting. Change the Pr. 14 Load pattern selection setting. (V/F control)
· Set stall prevention operation current in Pr. 22 Stall prevention operation level. (The initial value is
120%.) 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.)
· Check the connection of the IPM motor.
oL
Stall prevention (overcurrent)
· If the regenerative energy of the motor becomes excessive and exceeds the
regenerative energy consumption capability, this function stops the decrease in
frequency to prevent overvoltage trip. As soon as the regenerative energy has
During
decreased, deceleration resumes.
deceleration
· If the regenerative energy of the motor becomes excessive when regeneration
avoidance function is selected (Pr. 882 = 1), this function increases the speed to
prevent overvoltage trip. (Refer to page 200.)
· Check for sudden speed reduction.
· Regeneration avoidance function (Pr. 882 to Pr. 886) is being used? (Refer to page 279.)
The deceleration time may change.
Increase the deceleration time using Pr. 8 Deceleration time.
PS
PU stop
Stop with of PU is set in Pr. 75 Reset selection/disconnected PU detection/PU stop selection. (For Pr. 75,
refer to page 198.)
Check for a stop made by pressing
Turn the start signal OFF and release with
FR-PU04
OL
FR-PU07
FR-PU04
oL
FR-PU07
FR-PU04
PS
FR-PU07
of the operation panel.
.