Mitsubishi Electric 800 Series Instruction Manual page 19

 Error
Operation panel
indication
• The RES signal is turned ON.
Description
• This error may occur when the voltage at the input side of the inverter drops.
Corrective action • Turn OFF the RES signal.
 Warning
Output is not shut off when a protective function is activated.
 Stall prevention (overcurrent)
Operation panel
indication
• 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.
• Set a larger value in Pr.7 and Pr.8.
• Reduce the load.
• Try Advanced magnetic flux vector control or Real sensorless 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 initial value
is 150% for the ND rating.) 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 OLC operation.)
Reference FR-E800 Instruction Manual (Function)
 Stall prevention (overvoltage)
Operation panel
indication
• 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.
• 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, Pr.883, Pr.885, and Pr.886) is being used.
Corrective action The deceleration time may change. Increase the deceleration time using Pr.8 Deceleration time.
Reference FR-E800 Instruction Manual (Function)
Err.
OLC
When the output current (output torque under Real sensorless vector control) of the
inverter 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 output current (output torque under Real sensorless vector control) of the
inverter exceeds the stall prevention level (Pr.22 Stall prevention operation level, etc.),
this function reduces 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 output current (output torque under Real sensorless vector control) of the
inverter 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.
OLV
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.
FR-LU08 indication OL
FR-LU08 indication oL
2.5 Causes and corrective actions
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2. Protective Functions