Mitsubishi Electronics 520 540 Air Conditioner User Manual


 
174
Errors (Alarms)
(3) Warnings
*3. The stall prevention operation current can be set as desired. It is factory-set to
120%.
Operation Panel Indication
OL FR-PU04 OL
Name Stall prevention (overcurrent)
Description
During
acceleration
If a current of more than 120% (* 3) of the rated
inverter current flows in the motor, this function
stops the increase in frequency until the overload
current decreases to prevent the inverter from
resulting in overcurrent shut-off. When the overload
current has decreases below 120%, this function
increases the frequency again.
During
constant-
speed
operation
If a current of more than 120% (* 3) of the rated
inverter current flows in the motor, this function
lowers the frequency until the overload current
decreases to prevent overcurrent shut-off. When
the overload current has reduced below 120%, this
function increases the frequency up to the set
value.
During
deceleration
If a current of more than 120% (* 3) of the rated
inverter current flows in the motor, this function
stops the decrease in frequency until the overload
current decreases to prevent the inverter from
resulting in overcurrent shut-off. When the overload
current has decreases below 120%, this function
decreases the frequency again.
Check point
Check the motor for use under overload.
Corrective action
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. 21
"stall prevention function selection".
Check that the torque boost (Pr. 0) setting is not higher than
required.
Operation Panel Indication
oL FR-PU04 oL
Name Stall prevention (overvoltage)
Description
During
deceleration
If the regenerative energy of the motor increases
too much to exceed the brake capability, this
function stops the decrease in frequency to prevent
overvoltage shut-off. As soon as the regenerative
energy has reduced, deceleration resumes.
Check point
Check for sudden speed reduction.
Corrective action
The deceleration time may change. Increase the deceleration time
using Pr. 8 "deceleration time".