Motor Rotates In Opposite Direction; Speed Greatly Differs From The Setting; Acceleration/Deceleration Is Not Smooth; Motor Current Is Large - Mitsubishi Electric FR-A700 Series Instruction Manual

4.6.4 Motor rotates in opposite direction

Check that the phase sequence of output terminals U, V and W is correct.
Check that the start signals (forward rotation, reverse rotation) are connected properly. (Refer to page 78)

4.6.5 Speed greatly differs from the setting

Check that the frequency setting signal is correct. (Measure the input signal level.)
Check that the Pr. 1, Pr. 2, Pr. 19, Calibration parameter C2 to C7 settings are correct
Check that the input signal lines are not affected by external noise.
(Use shielded cables)
Check that the load is not too heavy.
Check that the Pr. 31 to Pr. 36 (frequency jump) settings are correct.

4.6.6 Acceleration/deceleration is not smooth

Check that the acceleration and deceleration time settings are not too short.
Check that the load is not too heavy.
Check that the torque boost (Pr. 0, Pr. 46, Pr. 112) setting is not too large to activate the stall function (torque
limit).

4.6.7 Motor current is large

Check that the load is not too heavy.
Check that the Pr. 0 Torque boost setting is correct.
Check that the Pr. 3 Base frequency setting is correct.
Check that the Pr. 14 Load pattern selection setting is appropriate.
Check that the Pr. 19 Base frequency voltage setting is correct.

4.6.8 Speed does not increase

Check that the maximum frequency (Pr. 1) setting is correct. (If you want to run the motor at 120Hz or
more, set Pr. 18 High speed maximum frequency. (Refer to
Check that the load is not too heavy.
(In agitators, etc., load may become heavier in winter.)
Check that the torque boost (Pr.0, Pr.46, Pr.112) setting is not too large to activate the stall function under V/F
control.
Check that the brake resistor is not connected to terminals P/+-P1 accidentally.

4.6.9 Speed varies during operation

When advanced magnetic flux vector control, real sensorless vector control, vector control or encoder
feedback control is exercised, the output frequency varies with load fluctuation between 0 and 2Hz. This is
a normal operation and is not a fault.
1) Inspection of load
Check that the load is not varying.
2) Check the input signals
Check that the frequency setting signal is not varying.
Check that the frequency setting signal is not affected by noise. Input filter to the analog input
terminal using Pr. 74 Input filter time constant and Pr. 822 Speed setting filter 1.
Check for a malfunction due to undesirable currents when the transistor output unit is connected.
(Refer to page 24)
3) Others
Check that the settings of Pr. 80 Motor capacity and Pr. 81 Number of motor poles are correct to the
inverter capacity and motor capacity under advanced magnetic flux vector control, real sensorless
vector control or vector control.
Check that the wiring length is not exceeding 30m when advanced magnetic flux vector, real
sensorless vector control or vector control is exercised. Perform offline auto tuning. (Refer to
Instruction Manual (applied))
Check that the wiring length is not too long for V/F control
Check first when you have troubles
Instruction Manual (applied).))
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