105
"B" Group: Fine Tuning Functions Section 3-6
between these two is done by assigning "39 (OLR)" to an intelligent input ter-
minal and make it ON/OFF.
When the inverter detects an overload, it must decelerate the motor to reduce
the current until it is less than the threshold. You can choose the rate of decel-
eration that the inverter uses to lower the output current.
Over-current Trip Suppres-
sion: B027 – The Over-current
Trip Suppression function moni-
tors the motor current and
actively changes the output fre-
quency profile to maintain the
motor current within the limits.
Although "LAD" refers to "linear
acceleration / deceleration", the
inverter only "STOPs" the accel-
eration and deceleration ramp so
that it will not cause an over-cur-
rent trip event.
The graph at right shows an
inverter output profile that starts
acceleration to a constant
speed. At two different points
during the acceleration, motor
current increases and exceeds
the fixed level of Over-current Trip Suppression level.
When the Over-current Trip Suppression feature is enabled by B027=01, the
inverter stops the acceleration ramp in each case until the motor current level
is again less than the threshold value, which is approximately 180% of the
rated current of the inverter.
When using the Over-current Trip Suppression feature, please note the follow-
ing:
• When the feature is enabled (B027=01), the actual acceleration may be
longer than the value set by parameters F002/F202 in some cases.
• The Over-current Trip Suppression feature does not operate by maintain-
ing a constant motor current. So it is still possible to have an over-current
trip event during extreme acceleration.
Motor
current
0
t
Output
frequency
0
t
Stops accel
Resumes accel
B027 = 01
OC LAD STOP = Enabled
Set acc time
Actual acc time
Approx. 150% of the inverter
rated current
"B" Function Run
Mode
Edit
Defaults
Func.
Code
Name Description EU Units
B021 Overload restriction operation
mode
Select the operation mode during
overload conditions, four options,
option codes:
00 Disabled
01 Enabled for acceleration and
constant speed
02 Enabled for constant speed
only
03 Enabled for acceleration and
constant speed, increase
speed at regen.
8 01 –
B221 Overload restriction operation
mode, 2nd motor
8 01 –
B022 Overload restriction level Sets the level of overload restric-
tion, between 20% and 200% of
the rated current of the inverter,
setting resolution is 1% of rated
current
8 Rated
curr.
x1.5
Amps
B222 Overload restriction level,
2
nd
motor
8 Rated
curr.
x1.5
Amps
To Next Page
Loading...
