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Troubleshooting; Motor Remains Stopped; Motor Rotates In Opposite Direction; Speed Greatly Differs From The Setting - Mitsubishi Electric FR-A500 Instruction Manual

Transistorized inverter.
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5.2 Troubleshooting

POINT: Check the corresponding areas. If the cause is still unknown, it is recommended to initialize the
parameters (return to factory settings), re-set the required parameter values, and check again.

Motor remains stopped

1) Check the main circuit
Check that a proper power supply voltage is applied (operation panel display is provided).
Check that the motor is connected properly.
Check that the conductor across P<+>-P1 is connected.
2) Check the input signals
Check that the start signal is input.
Check that both the forward and reverse rotation start signals are not input.
Check that the frequency setting signal is not zero.
Check that the AU signal is on when the frequency setting signal is 4 to 20mA.
Check that the output stop signal (MRS) or reset signal (RES) is not on.
Check that the CS signal is not off when automatic restart after instantaneous power failure is
selected (Pr. 57 = other than "9999").
Check that the sink/source jumper connector is fitted securely.
3) Check the parameter settings
Check that the reverse rotation prevention (Pr. 78) is not selected.
Check that the operation mode (Pr. 79) setting is correct.
Check that the bias and gain (Pr. 902 to Pr. 905) settings are correct.
Check that the starting frequency (Pr. 13) setting is not greater than the running frequency.
Check that various operational functions (such as three-speed operation), especially the maximum
frequency (Pr. 1), are not zero.
4) Check the load
Check that the load is not too heavy.
Check that the shaft is not locked.
5) Others
Check that the ALARM lamp is not lit.
Check that the Pr. 15 "jog frequency" setting is not lower than the Pr. 13 "starting frequency" value.

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.

Speed greatly differs from the setting

Check that the frequency setting signal is correct. (Measure the input signal level.)
Check that the following parameter settings are proper: Pr. 1, Pr. 2, Pr. 19, Pr. 902 to Pr. 905.
Check that the input signal lines are not affected by external noise. (Use shielded cables)
Check that the load is not too heavy.

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.

Motor current is large

Check that the load is not too heavy.
Check that the torque boost (Pr. 0, Pr. 46, Pr. 112) setting is not too large.
Check that the set value of the load pattern selection (Pr. 14) is proper for the application.


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