12. 4 How to check other troubles

Expected causes of other troubles (abnormal operations and conditions) and measures to settle those troubles are shown below.

Abnormal

Causes and measures

operation/condition

 

 

Change phase sequence of output terminals U, V and W.

Motor runs reversely.

Change forward and reverse signal inputs of external operation signals for

 

each other. (Refer to 7.2, Control terminal function allotment.)

 

Load to motor is too heavy.

 

Reduce the load.

 

Soft stall function is activated.

 

Switch off soft stall function. (Refer to 5.13.)

 

Setting values of maximum frequency  and upper limit frequency 

 

are low.

Motor runs but speed

Raise maximum frequency and upper limit frequency  to higher

level.

cannot be varied.

Frequency setting signal is low (weak).

 

Check input level of signal, circuit and connection, etc.

 

Check setup specifications of frequency setting signal (setting of point 1,

 

point 2). (Refer to 7.3.)

 

Check to see if stall prevention function is activated at low-speed operation

 

because of too high torque boost rate.

 

Adjust manual torque boost () and acceleration time #1 (). (Refer

 

to 5.12 and 5.1.)

Acceleration/deceleration

Acceleration time #1 () and deceleration time #1 () are set short.

of motor is rough.

Increase setting values of acceleration time #1 () and deceleration

time #1 ().

 

 

Load to motor is too heavy.

Large motor current

Reduce load to motor.

Check to see if torque boost rate is too high at low-speed operation. (Refer

 

 

to 5.12.)

 

Improper voltage setting for the motor.

 

Set voltage properly to the motor.

 

Terminal voltage of the motor is low.

Motor speed is high or

Check setting value of base frequency voltage #1 (). (Refer to

6.13.6.) Change the cable for thicker one.

low.

Improper gear ratio for acceleration and deceleration.

 

Change gear ratio properly for smooth acceleration and deceleration.

 

Output frequency is set improperly.

 

Check setup of output frequency range.

 

Tune basic frequency. (Refer to 5.9.)

 

Load to the motor is too heavy or light.

 

Reduce load fluctuation.

Motor speed varies in

Rating of inverter or motor is improper to load.

Change the motor or inverter for another of higher rating.

operation.

Check to see if frequency setting signal input fluctuates.

 

 

If V/f control parameter is set at 3 or larger, check setting value and setup

 

conditions of vector control. (Refer to 5.10.)

Some or all of six keys

Change panel operation prohibition parameter . (Refer to 6.30.14.)

on operation panel don't

*Parameter is occasionally set for key operation prohibition mode. Cancel

work.

key operation prohibition mode according to the following procedure.

Access to parameter

Press the [] key twice while pressing the [ENT] key.

results in failure.

1: If parameter setting prohibition parameter is set at ""(prohibited),

Parameter cannot be

changed.

change the setting to "" (allowed).

Monitor (display) is

2: If there is an input terminal that is set for "" (or "") (parameter

uncontrollable.

editing enabling) by input terminal function parameter, turn on the terminal.

Measures against trouble with parameter setting

How to check the

Changed parameters can be searched and reset.

parameters that have

For details, refer to 4.1.3.

been changed.

 

How to reset changed

Parameters whose values have been changed can be reset to their

parameters to default

respective default values in bulk.

values

For details, refer to 4.1.5.

L-7

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Toshiba VF-A7 instruction manual How to check other troubles, Measures against trouble with parameter setting