PROTECTIVE FUNCTIONS
146
(3) Warnings
FR-PU04 Indication
OL (Stll Prev STP)
Name
Stall prevention (overcurrent)
During
acceleration
If a current of more than 150% (Note 4) of
the rated inverter current flows in the
motor, this function stops the increase in
frequency until the overload current
reduces to prevent the inverter from
resulting in overcurrent shut-off. When the
overload current has reduced below 150%,
this function increases the frequency
again.
During
constant-speed
operation
If a current of more than 150% (Note 4) of
the rated inverter current flows in the
motor, this function lowers the frequency
until the overload current reduces to
prevent overcurrent shut-off. When the
overload current has reduced below 150%,
this function increases the frequency up to
the set value.
Description
During
deceleration
If a current of more than 150% (Note 4) of
the rated inverter current flows in the
motor, this function stops the decrease in
frequency until the overload current
reduces to prevent the inverter from
resulting in overcurrent shut-off. When the
overload current has reduced below 150%,
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. 156 "stall prevention operation selection".
Note:4 The stall prevention operation current can be set as desired. It is factory-set to
150%.
FR-PU04 Indication
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".
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