Inovance MD500 Series - Page 133

6. Description of Parameters
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6
Function Code Parameter Name Setting Range Default
F3-18
Current limit level 50% to 200% 150%
F3-19
Current limit selection 0: Disabled
1: Enabled
1
F3-20
Current limit gain 0 to 100 20
F3-21
Compensation factor of speed
multiplying current limit
50% to 200% 0
In high frequency area, motor drive current is small. Bigger motor speed dip is caused by current
limit level compared with below rated frequency. To improve motor running characteristic, you
can lower current limit level above rated frequency.
The current limit function above rated frequency helps to improve acceleration performance in
the applications, such as centrifuge, where high running frequency and several times of field
weakening are required, and load inertia is large.
The current limit level above rated frequency = (fs/fn) x k x LimitCur.
● fs: running frequency
● fn: rated motor frequency
● k: compensation factor of speed multiplying current limit level (F3-21)
● LimitCur: current limit level (F3-18)
Figure 6-41 Current limit above rated frequency
Rated
frequency
Twice of rated
fruquency
Current limit level
above rated frequency
Note
● Current limit level 150% indicates 1.5 times of rated current of the AC drive.
● For high-power motor with carrier frequency below 2 kHz, lower the current
limit level. This is because the overcurrent fast prevention function is enabled in
advance of the current limit function due to increase of pulsating current, which
will result in insufcient torque output.