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Chapter 6 P4 input terminal
Inverter output current (torque) limit In the acceleration, constant speed, deceleration process,
if the current exceeds the overcurrent loss current point (150%), the overcurrent speed will
work.
When the current exceeds the over-discharge speed point, the output frequency begins to
decrease. Until the current returns below the over-discharge speed point, the frequency begins
to accelerate upward to the target frequency. The actual acceleration time is automatically
lengthened. If the actual acceleration time does not meet the requirements, it may be
appropriate. Increase "F1-21 over-current operating current"
。
P3-18
Overcurrent current
50~200%
Default
：
150%
P3-19
Over-speed suppression
0 is invalid, 1 is
valid
Default
：
1
P3-20
Over-speed rejection gain
0~100
Default
：
20
P3-21
Double speed overrun speed action current
compensation coefficient
50~200%
Default
：
50%
In the high frequency region, the motor drive current is small, and the speed of the
motor drops greatly with respect to the same stall current below the rated frequency. In
order to improve the operating characteristics of the motor, the stall operating current
above the rated frequency can be reduced, in some centrifuges. When the operating
frequency is high, requiring several times of weak magnetic field and large load inertia,
this method has a good effect on the acceleration performance.
Transition stall current exceeding the rated frequency = (fs/fn) * k * LimitCur;
Fs is the running frequency, fn is the rated motor frequency, k is F3-21 "double speed
over loss speed action current compensation coefficient", LimitCur is F3-18 "overcurrent
speed action current";
Overcurrent loss current 150% means 1.5 times the rated current of the inverter;
For high-power motors, the carrier frequency is below 2 kHz. Due to the increase of
the ripple current, the wave-by-wave current-limit response starts before the over-speed
prevention action, and the torque is insufficient. In this case, reduce the over-speed
prevention operation current.
● Inverter bus voltage limit (and brake resistor turn-on voltage setting)
If the bus voltage exceeds the overvoltage stall point of 760V, indicating that the
electromechanical system is already in the power generation state (motor speed > output
frequency), the overvoltage stall will work, adjust the output frequency (consuming more
feedback than the feedback), the actual deceleration time will be automatic Stretching,
avoiding trip protection, if the actual deceleration time can not meet the requirements, you
can increase the overexcitation gain appropriately.
