6. Control Functions and Parameter Settings
6-67
C22-0
Overload setting (L0)
C22-1
0Hz overload (L2)
C22-2
0.7 Fbase freq. overload (L1)
These are setting parameters for the overload
(OLT) function.
The reverse time interval characteristics will
change with the C22-0 setting as shown on the
right.
The setting uses the motor rated current (B00-6,
B01-6) as 100%.
(Note 1)
Do not set a value that exceeds the
inverter rated current.
When running a self-cooling type motor at a low
speed, set C22-1 and C22-2 according to the
motor characteristics. The characteristics will be
as shown on the right.
(Note 2)
At 1.0Hz or less, the inverter will trip
at 75% of the inverter’s rated current
in one minute.
(Note 3)
If the inverter output current exceeds
155%, the inverter will trip at 170% of
the rated current in 2.5 seconds.
(Note 4)
The above overload characteristics
apply to V/f control (constant torque
load) (C30-0 = 1), sensor-less vector
control (C30-0 = 3), and vector
control with sensor (C30-0 = 4).
Refer to section 6-6 for the overload
characteristics when V/f control
(variable torque load) is selected
(C30-0 = 2).
C22-4
Motor loss braking setting
This parameter sets output voltage increase at the base frequency, in percentage respect to
the rated output voltage (B00-3). Normally, this is set to 50% of the specified value.
When the DC voltage attempts to rise due to deceleration operation or a regenerative load,
the motor loss braking function raises the inverter output voltage and decreases the motor
efficiency to prevent tripping by an overvoltage. This function is valid only when the motor
loss braking is selected with the DBR option selection (C31-0 = 3, 4) in the V/f control mode
(C30-0 = 1, 2).
(Note 1) Take care to motor heating.
(Note 2) If the normal V/f setting is inappropriate, the motor efficiency will increase when the
voltage is increased and thus tripping by overvoltage could occur easily.
Trip tim e
(m in ute)
2
1
5 0%
1 00 %
1 50 %
C 2 2 -0 =5 0 %
O utpu t c u rren t
B 2 2-0 =1 00 %
C 22-0
C 22-2
C 22-1
O verload referenc e
(L2)
B as e F re qu e nc y x 0 .7
B as e freq ue n cy
(B 0 0-5 , B 01 -5 )
(L1)
(L0)