Hitachi SJ7002 Series Instruction Manual page 252

6–4
Troubleshooting
Symptom/condition
The motor speed will not reach
the target frequency (desired
speed).
The rotation is unstable.
The RPM of the motor does not
match the inverter output
frequency setting.
True for certain
A parameter
parameters
will not
change after
an edit
True for all
(reverts to
parameters
old setting).
Probable Cause
• If using the analog input, is there
current or voltage at [O] or [OI]?
• Is the load too heavy?
• Is the inverter internally limiting the
output frequency?
• Is the load fluctuation too great?
• Is the supply voltage unstable?
• Is the problem occurring at a particular
frequency?
• Is the maximum frequency setting
A004 correct?
• Does the monitor function D001
display the expected output frequency?
• Is the inverter in Run Mode? Some
parameters cannot be edited during
Run Mode.
• If you're using the [SFT] intelligent
input (software lock function)—is the
[SFT] input ON?
Solution
• Check the wiring.
• Check the potentiometer or signal
generating device.
• Reduce the load.
• Heavy loads activate the overload
restriction feature (reduces output as
needed).
• Check max frequency setting
(A004)
Check frequency upper limit
•
setting (A061)
If using analog inputs, check
•
their settings (A101– A104) or
(A111–A114), or (A011–A014)
• Increase the motor capacity (both
inverter and motor).
• Fix power supply problem.
• Change the output frequency
slightly, or use the jump frequency
setting to skip the problem
frequency.
• Verify the V/F settings match motor
specifications.
• Make sure all scaling (such as A011
to A014) is properly set.
• Put inverter in Stop Mode (press the
Stop/reset key). Then edit the
parameter.
• Change the state of the SFT input,
and check the B031 parameter (SFT
mode).