Troubleshooting In The Speed Control - Mitsubishi Electric FR-A800 Series Instruction Manual

5.3.6
Sensorless Vector Vector Vector
Sensorless Sensorless
No. Condition
The motor does not
1 rotate. (Vector
control)
Motor does not run at
the correct speed.
2 (Command speed
and actual speed
differ.)
The speed does not
3 accelerate to the
command speed.
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Troubleshooting in the speed control

PM PM PM
Possible cause
Motor wiring is incorrect.
Encoder type selection
switch (Vector control
compatible option) is
incorrect.
The wiring of the
encoder is incorrect.
The parameter setting
and the number of
encoder pulses used are
different.
Encoder power
specifications are
incorrect. Alternatively,
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 motor constant
varies due to increase in
the motor temperature.
Torque shortage.
The torque limit is
operating.
Only P (proportional)
control is performed.
5.3 Speed control under Real sensorless vector control, vector control, PM sensorless vector control
search engine
Countermeasure
• 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 at Vector control setting, rotate
the motor counterclockwise and check if FWD is indicated.
If REV is indicated, the phase sequence of the encoder is incorrect.
Check the wiring, and set Pr.359 (Pr.852) Encoder rotation direction in
accordance with the motor specification. (Refer to
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 does not rotate. Set Pr.369 (Pr.852) Number of encoder pulses
correctly. (Refer to page 87.)
• 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 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 226.)
• Check that the speed command sent from the controller is correct. (Take EMC
measures.)
• Lower the setting of Pr.72 PWM frequency selection.
• Adjust the bias and gain Pr.125, Pr.126, C2 to C7, C12 to C15 of the speed
command again.
• Check the settings of Pr.369 (Pr.851) (under Vector control). (Refer to
Enable the online auto tuning at startup (set Pr.95 (Pr.574) = "1") (under Real
sensorless vector control). (Refer to
To perform the online auto tuning at startup for a lift, use of the Start-time tuning
start external input (X28) signal is recommended.
• Raise the torque limit.
(Refer to the torque limit for speed control on
• Increase the capacity.
• Speed deviation occurs under P (proportional) control when the load is heavy.
Select PI control.
page 87.)
page 558.)
page 245.)
5. PARAMETERS
1
2
3
4
5
6
7
8
9
10
page 87.)
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