Speed control under Real sensorless vector control, vector control, PM sensorless vector control
Troubleshooting in the speed control
The motor does not
Motor does not run
at the correct
and actual speed
The speed does not
accelerate to the
Motor wiring is incorrect.
Encoder type selection
switch (Vector control
compatible option) is
Wiring of encoder is
The parameter setting
and the number of
encoder pulses used are
power is not input.
The option to be used
and parameter settings
do not match.
Speed command from
the controller is different
from the actual speed.
The speed command is
affected by noise.
The command speed
and the speed
recognized by the
inverter are different.
The setting for the
number of encoder
pulses is incorrect.
The torque limit is
Only P (proportional)
control is performed.
Check the wiring.
Set V/F control (set Pr. 80 "Motor capacity" or Pr. 81 "Number of
motor poles" to "9999") and check the motor rotation direction.
For SF-V5RU (1500 r/min series), set Pr. 19 "Base frequency
voltage" to "170 V (340 V)" when the value is 3.7 kW or lower,
and set it to "160 V (320 V)" when the value is higher, and set
Pr. 3 "Base frequency" to "50 Hz".
When a forward signal is input, rotation in the
counterclockwise direction as viewed from the
motor shaft direction is correct. (Clockwise
rotation means that the phase sequence of the
inverter secondary side wiring is different.)
Check the encoder specifications.
Check the encoder type selection switch of differential/
complementary (Vector control compatible option).
When using the system where the motor shaft can be rotated
by an external force other than the motor without any safety
troubles, rotate the motor counterclockwise and check if FWD is
If REV is indicated, the phase sequence of the encoder is
Check the wiring, and set Pr. 359 (Pr.852)"Encoder rotation
direction" in accordance with the motor specification.
(Refer to page 2-71.)
If the clockwise direction is forward as viewed from the motor
shaft side, set Pr. 359 (Pr.852)= "0".
If the counterclockwise direction is forward as viewed from the
motor shaft side, set Pr. 359 (Pr.852)= "1".
If the parameter setting value is lower than the number of
encoder pulses used, the motor will not rotate. Set Pr. 369 (Pr.
851) "Number of encoder pulses" correctly.
Check the encoder power specifications (5 V/12 V/15 V/24 V),
and input the external power supply. When the encoder output
is the differential line driver type, only 5 V can be input. Make
the voltage of the external power supply the same as the
encoder output voltage, and connect the external power
supply between PG and SD.
Correctly set Pr. 862 "Encoder option selection" according to
the option to be used. (Refer to page 5-69.)
Check that the speed command sent from the controller is
correct. (Take EMC measures.)
Set Pr. 72 "PWM frequency selection" lower.
Adjust the bias and gain (Pr. 125, Pr. 126, C2 to C7, C12 to C15)
of the speed command again.
Check the setting of Pr. 369 (Pr. 851)"Number of encoder pulses"
(vector control). (Refer to page 2-83.)
Raise the torque limit.
(Refer to the torque limit for speed control on page 5-90.)
Increase the capacity.
Speed deviation occurs under P (proportional) control when
the load is heavy. Select PI control.
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