Mitsubishi Electric FR-A800, Instruction Manual

Page: 326 / 1042

Torque control under Real sensorless vector control and vector control Parameters
5 - 146
5.4.7 Troubleshooting in torque control
Condition Cause Countermeasure
1
Torque control does not
operate properly.
앫
There is incorrect phase
sequence between the
motor wiring and encoder
wiring.
앫
Check the wiring. (Refer to page 2-67.)
앫
Pr. 800 "Control method
selection" setting is applied.
앫
Check the setting of Pr. 800. (Refer to page 5-56.)
앫
Speed limit value has not
been input.
앫
Set speed limit value. (If speed limit value is not
input, it becomes 0 Hz by default and the motor
does not run.)
앫
Torque command varies.
앫
Check that the torque command sent from the
controller is correct.
앫
Set Pr. 72 "PWM frequency selection" lower.
앫
Set Pr. 826 "Torque setting filter 1" higher.
앫
The torque command and
the torque recognized by the
inverter are different.
앫
Re-calibrate the C16 "Terminal 1 bias command
(torque)", C17 "Terminal 1 bias (torque)", C18
"Terminal 1 gain command (torque)", and C19
"Terminal 1 gain (torque)".
(Refer to page 5-409.)
앫
Torque fluctuation due to
motor temperature variation
앫
Select the magnetic flux observer by Pr. 95 "Online
auto tuning selection". (Refer to page 5-465.)
앫
The option to be used and
parameter settings do not
match.
앫
Correctly set Pr. 862 "Encoder option selection"
according to the option to be used (refer to page
5-64 ).
2
When a small torque
command is given, the
motor rotates in a
direction opposite to
the start signal.
앫
Torque offset calibration is
inaccurate.
앫
Re-calibrate C16 "Terminal 1 bias command
(torque)" and C17 "Terminal 1 bias (torque)". (Refer
to page 5-409.)
3
Torque control cannot
operate normally during
acceleration/
deceleration.
The motor vibrates.
앫
Speed limit is operating.
(Speed limit may operate
because the speed limit
value will increase or
decrease according to
acceleration/deceleration
time setting of Pr. 7 and Pr. 8
when Pr. 807 = "0 or 2".)
앫
Set the acceleration/deceleration time shorter.
Alternatively, set acceleration/deceleration time to
"0". (Speed limit during acceleration/deceleration
is determined by the speed limit for constant
speed.)
4
Output torque is
nonlinear for the torque
command.
앫
Torque shortage
앫
Return Pr. 854 "Excitation ratio" to the initial value.
Tab. 5-52: Troubleshooting during torque control
Parameters referred to
Pr. 72 PWM frequency selection => page 5-219
Pr. 178 to Pr. 189 (input terminal function selection) => page 5-422
Pr. 800 Control method selection => page 5-56
Pr. 807 Speed limit selection => page 5-146
C16 to C19 (torque setting voltage (current) bias/gain) => page 5-409
Sensorless Sensorless Sensorless Vector Vector Vector