Speed Does Not Accelerate - Mitsubishi Electric FR-A800 Series Instruction Manual

6.6.12 Speed does not accelerate

Check
point
The start command or frequency
command is chattering.
The wiring length is too long for the analog
Input
frequency command, causing a voltage
signal
(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 the calibration
parameter C2 to C7 settings are not
appropriate.
The maximum voltage (current) input
value is not set during the External
operation. (Pr.125, Pr.126, Pr.18)
The torque boost (Pr.0, Pr.46, Pr.112)
setting is not appropriate under V/F
control, so the stall prevention function is
activated.
The V/F pattern is not appropriate when V/
F control is performed. (Pr.3, Pr.14, Pr.19)
Parameter
setting
The stall prevention (torque limit) function
is activated due to a heavy load.
Auto tuning is not performed under
Advanced magnetic flux vector control,
Real sensorless vector control, or Vector
control.
The setting of pulse train input is not
appropriate.
During PID control, the output frequency is automatically controlled so that the measured value equals the set
point.
A brake resistor is connected across
Main
terminals P/+ and P1 or across P1 and PR
circuit
by mistake.
808
6. PROTECTIVE FUNCTIONS
6.6 Check first when you have a trouble
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Countermeasure
Check if the start command and the frequency command are correct. —
Perform the bias and gain calibration for the analog input.
Take countermeasures against EMI, such as using shielded wires for
input signal lines.
Check the settings of Pr.1 and Pr.2. To operate at 120 Hz or higher,
set Pr.18 High speed maximum frequency.
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.
Increase/decrease the Pr.0 Torque boost setting value by 0.5%
increments so that stall prevention does not occur.
Set the 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 the Pr.14 Load pattern selection setting according to the
load characteristic.
Reduce the load weight.
Set Pr.22 Stall prevention operation level (Torque limit 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).
Connect an optional brake resistor (FR-ABR) across terminals P/+
and PR.
Refer to
page
505
118
428
505
428, 505
706
707
708
—
245, 431
—
532
406
601
97