Speed Varies During Operation; Operation Mode Is Not Changed Properly; Operation Panel (Fr-Du07) Display Is Not Operating; Power Lamp Is Not Lit - Mitsubishi Electric FR-A740-00023 Instruction Manual

Check first when you have troubles

5.5.9 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 27)
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 control, real
sensorless vector control or vector control is exercised. Perform offline auto tuning. (Refer to pege 181)
Check that the wiring length is not too long for V/F control.
Change the Pr. 19 Base frequency voltage setting (about 3%) under V/F control.

5.5.10 Operation mode is not changed properly

If the operation mode does not change correctly, check the following:
1) Inspection of load
Check that the STF or STR signal is off.
When it is on, the operation mode cannot be changed.
2) Parameter setting
Check the Pr. 79 setting.
When the Pr. 79 Operation mode selection setting is "0" (initial value), the inverter is placed in the
external operation mode at input power-on. At this time, press
when the parameter unit (FR-PU04/FR-PU07) is used) to switch to the PU operation mode.

5.5.11 Operation panel (FR-DU07) display is not operating

Check that the operation panel is connected to the inverter securely.

5.5.12 POWER lamp is not lit

Check that wiring is securely performed and installation is correct.

5.5.13 Parameter write cannot be performed

Make sure that operation is not being performed (signal STF or STR is not ON).
Make sure that you are not attempting to set the parameter in the external operation mode.
Check Pr. 77 Parameter write selection.
Check Pr. 161 Frequency setting/key lock operation selection.
410
on the operation panel (press