Speed Does Not Accelerate - Mitsubishi Electric FR-F800 Instruction Manual

Check first when you have a trouble
6.6.12

Speed does not accelerate

Check
points
Start command and frequency command are
chattering.
The wiring length used for analog frequency
Input
command is too long, and it is causing a
signal
voltage (current) drop.
The input signal lines are affected by external
EMI.
Pr.1 Maximum frequency, Pr.2 Minimum
frequency, Pr.18 High speed maximum
frequency, and calibration parameter C2 to
C7 settings are improper.
The maximum voltage (current) input value is
not set during the External operation. (Pr.125,
Pr.126, Pr.18)
Torque boost (Pr.0, Pr.46) setting is improper
under V/F control, so the stall prevention
function is activated.
V/F pattern is improper when V/F control is
Parameter
performed.
Setting
(Pr.3, Pr.14, Pr.19)
Stall prevention function is
activated due to a heavy load.
Auto tuning is not performed under Advanced
magnetic flux vector control.
The setting of pulse train input is improper.
During PID control, output frequency is automatically controlled to make measured value = set point.
558
PROTECTIVE FUNCTIONS
Possible cause Countermeasure
Check if the start command and the frequency command are
correct.
Perform Analog input bias/gain calibration.
Take countermeasures against EMI, such as using shielded
wires for input signal lines.
Check the settings of Pr.1 and Pr.2 and set Pr.18.
Check the calibration parameter C2 to C7 settings.
Check the settings of Pr.125 Terminal 2 frequency setting
gain frequency and Pr.126 Terminal 4 frequency setting
gain frequency.
To operate at 120 Hz or higher, set Pr.18 High speed
maximum frequency.
Increase/decrease the Pr.0 Torque boost setting value by
0.5% increments so that stall prevention does not occur.
Set rated frequency of the motor to Pr.3 Base frequency.
Use Pr.19 Base frequency voltage to set the base voltage (for
example, rated motor voltage).
Change Pr.14 Load pattern selection according to the load
characteristic.
Reduce the load weight.
Set Pr.22 Stall prevention operation level higher according to
the load. (If Pr.22 is set too high, an overcurrent trip (E.OC[]) is
likely to occur.)
Check the capacities of the inverter and the motor.
Perform offline auto tuning.
Check the specification of the pulse generator (open collector
output or complementary output) and check the adjustment of
the pulse train and frequency (Pr.385 Frequency for zero
input pulse and Pr.386 Frequency for maximum input
pulse).
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