5-44
F43, F44
Current Limiter (Mode selection, Level)
When the output current of the inverter exceeds the level specified by the current limiter (F44),
the inverter automatically manages its output frequency to prevent a stall and limit the output
current. (Refer to the description of function code H12.)
If F43 = 1, the current limiter is enabled only during constant speed operation. If F43 = 2, the
current limiter is enabled during both of acceleration and constant speed operation. Choose
F43 = 1 if you need to run the inverter at full capability during acceleration and to limit the
output current during constant speed operation.
For single-phase 100 V class series
The limiting level setting (F44) should be calculated from the current limiting level
I
limit
(A) based on the reference current
I
ref
(A), as shown below.
100
(A)
(A)
=
(%)
Setting
ref
limit
I
I
(Example) Setting the current limiting level
I
limit
at 4.2 A for 1 HP standard motors
84
100
(A)
5.0
(A)
4.2
=
(%)
Setting
The reference current is given in the table for F20 to F22.
Mode selection (F43)
F43 selects the motor running state in which the current limiter will be active.
Data for
F43
Running states that enable the current limiter
During acceleration
During constant speed
During deceleration
0
Disable
Disable
Disable
1
Disable
Enable
Disable
2
Enable
Enable
Disable
Level (F44)
F44 specifies the operation level at which the output current limiter becomes activated, in ratio
to the inverter rating.
• Since the current limit operation with F43 and F44 is performed by software, it
may cause a delay in control. If you need a quick response, specify a current limit
operation by hardware (H12 = 1) at the same time.
• If an excessive load is applied when the current limiter operation level is set
extremely low, the inverter will rapidly lower its output frequency. This may cause
an overvoltage trip or dangerous turnover of the motor rotation due to
undershooting.
