Mitsubishi Electric FR-A700 Technical Manual page 262

2.9.8 Troubleshooting (speed control)
Case
(1) The motor wiring is wrong
(2) Encoder specifications (encoder specification
(3) The encoder wiring is wrong.
Motor does not
1 rotate.
(vector control)
(4)The [Pr. 369 Number of encoder pulses] setting and
(5) Encoder power specifications are wrong. Or, power
(1) The speed command from the command
Motor does not run
at correct speed.
2 (Speed command (2) The speed command value does not match the
does not match
actual speed) (3) The number of encoder pulses setting is
(1) Insufficient torque.
Speed does not
3 rise to the speed
command. (2) Only P (proportional) control is selected.
Cause
selection switch (FR-A7AP, FR-A7AL)) are wrong
the number of encoder pulses used are
different.
is not input.
device is incorrect.
The speed command is compounded with noise.
inverter-recognized value.
incorrect.
Torque limit is activated.
A700
(A700)
(1) Wiring check
V/F control (set 9999 in either [Pr. 80] or [Pr. 81]) and
check the motor rotation direction.
Check the speed monitor output from output terminal FM.
For the FR-V5RU, set 170V for 3.7kW or less and 160V
for more in [Pr. 19 Base frequency voltage], and set 50Hz in
[Pr. 3 Base frequency].
(2) Check the encoder specifications
Check the encoder specifications selection switch (FR-
A7AP, FR-A7AL) of differential/complementary.
(3) Check that FWD is displayed when running the motor in
the counterclockwise direction from outside during a stop
of the inverter with vector control setting.
If REV is displayed, the encoder phase sequence is
wrong.
Perform the correct wiring or match the [Pr. 359 Encoder
rotation direction] setting.
[Pr. 359] Setting
0
1
(initial value)
(4) The motor will not run if the parameter setting is smaller
than the number of encoder pulses used. Set the [Pr. 369
Number of encoder pulses] correctly.
(5) Check the power specifications (5V/12V/15V/24V) of
encoder and input the external power supply.
(1) Check that a correct speed command comes from the
command device.
Decrease [Pr. 72 PWM frequency selection] .
(2) Readjust speed command bias/gain [Pr. 125, 126, C2 to
C7, C12 to C15].
(3)Check the setting of [Pr. 369 Number of encoder pulses].
(vector control)
(1)-1 Increase the torque limit value.
(Refer to torque limit of speed control on page 283)
(1)-2 Insufficient capacity
(2) When the load is heavy, speed deviation will occur under
P (proportional) control. Select PI control.
296
PARAMETER
Countermeasures
When the forward rotation signal is
input, the motor running in the
counterclockwise direction as viewed
from the motor shaft is normal. (If it runs
in the clockwise direction, the phase
sequence of the inverter secondary side
wiring is incorrect.)
Relationship between the
Motor and Encoder
A
Encoder
Clockwise direction as viewed
from A is forward rotation
CCW
A
Encoder
Counterclockwise direction as
viewed from A is forward rotation
CW