Chapter 6 - Parameter Description [FU2]
107
l Sensorless_S (Sensorless vector speed control)
Vector_SPD (Vector control speed) operation:
Use it when 1) high starting torque needed at low speed
2) load fluctuation is high 3) rapid response needed. To
activate this function, set FU2-30~37 and FU2-39
properly.
If not using LG 220V/440V Class motor: Set Yes in FU2-
40 [Auto tuning] first.
Vector_SPD control is Only valid when Sub-B board is
mounted (Speed-detecting Encoder installed to the
motor).
Conditions for Sensorless Vector Control
Conditions for sensorless control are as follows. If one of
the following conditions is not satisfied, the inverter may
malfunction with insufficient torque, irregular rotation, or
excessive motor noise. It is recommended to use V/F
control.
¨ Use a motor capacity that is equal to or one
horsepower lower than the inverter capacity.
¨ Two different kinds of motor parameters can be set
for one inverter, but use only one motor parameter
in Sensorless control mode.
¨ If the motor in use is not LG 220V/440V Class
motor or using 220V/380V dual use motor, utilize
the auto tuning feature in FU2-40 [Auto tuning]
before starting.
¨ Set appropriate values for the electronic thermal
function, the overload limit function and the stall
prevention. The set values should exceed 150% of
the rated motor current.
¨ When DRV–04 [Frequency Mode] is set to “V1”, “I”,
or “V1+I”, eliminate any potential noise influence
with the frequency reference.
¨ The number of the motor pole should be 2 pole, 4
pole, or 6 pole.
¨ The distance between the inverter and the motor
should not exceed 100m (328 ft).
Precautions When Using Sensorless Vector Control
¨ Forced-cooling should be used for the motor when
the average operating speed is under 20Hz and
more than 100% load is used constantly.
¨ The motor may rotate 0.5% faster than the
maximum speed if the motor temperature does not
reach normal operating temperature.
¨ Installing the DB (Dynamic Brake) braking unit
option can improve the performance during
regeneration for systems with frequent acceleration
and deceleration operations.
¨ Utilize the auto-tuning feature when the motor
reaches normal temperature (average temperature
where the motor normally operates).
¨ Output torque may be reduced when an output filter
option is used between the inverter and the motor.
¨ If the speed is unstable when the FU2–38 [Carrier
Frequency Selection] is set to a value more than
10kHz, change the setting to 5~10kHz.
¨ Over current fault can occur if the FU2-41 [Stator
Resistance (Rs)] is set to a value more than twice
the auto tuned value
¨ Max setting range is 300 Hz.
Detail Tuning Method for Sensorless Vector Control
¨ Adjust the FU2–34 [No Load Motor Current (RMS)]
value larger or smaller by 5% units if the current is
larger or smaller than that of V/F control with small
load.
¨ Adjust the FU2–32 [Rated Motor Slip] value larger
or smaller by 5% units if the speed is faster or
slower than that of V/F control with small load.
l Sensorless_T(Sensorless Vector Torque)
Operation:
All settings are the same as Sensorless_S except
using torque reference for torque control.
l Vector_TRQ (Vector control torque) Operation:
All settings are the same as Vector_SPD except
using torque reference for torque control.
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