How To Check Other Troubles - Toshiba TOSVERT VF-P7 Instruction Manual

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
operation/condition
Motor runs reversely.
Motor runs but speed
cannot be varied.
Acceleration/deceleration
of motor is rough.
Large motor current
Motor speed is high or
low.
Motor speed varies in
operation.
Some or all of six keys
on operation panel don't
work.
Access to parameter
results in failure.
Parameter cannot be
changed.
Monitor (display) is
uncontrollable.
Measures against trouble with parameter setting
How to check the
parameters that have
been changed.
How to reset changed
parameters to default
values
Causes and measures
･Change phase sequence of output terminals U, V and W.
･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.
Raise maximum frequency  and upper limit frequency  to higher
level.
･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 time #1 () and deceleration time #1 () are set short.
Increase setting values of acceleration time #1 () and deceleration
time #1 ().
･Load to motor is too heavy.
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.
Check setting value of base frequency voltage #1 (). (Refer to
6.13.6.) Change the cable for thicker one.
･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.
･Rating of inverter or motor is improper to load.
Change the motor or inverter for another of higher rating.
･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.)
･Change panel operation prohibition parameter . (Refer to 6.30.14.)
*Parameter is occasionally set for key operation prohibition mode. Cancel
key operation prohibition mode according to the following procedure.
Press the [△] key twice while pressing the [ENT] key.
1: If parameter setting prohibition parameter  is set at ""(prohibited),
change the setting to "" (allowed).
2: If there is an input terminal that is set for "" (or "") (parameter
editing enabling) by input terminal function parameter, turn on the terminal.
･ Changed parameters can be searched and reset.
For details, refer to 4.1.3.
･ Parameters whose values have been changed can be reset to their
respective default values in bulk.
For details, refer to 4.1.5.
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