AC70T Crane Purpose VFD Manual
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Chapter 7 Periodic Overhaul and Maintenance
7.1 Overhaul
Frequency inverter is composed by semi-conductive components, passive electronic component and motive
component. All of these components have useful life. Even under normal working environment, some of the
components can not work after the life time. To avoid malfunction, daily checking, periodic overhaul, component
changing and other maintenance should be carried out to prevent. We suggest one overhaul every 3-4 months after
installation.
●
Daily checking
To avoid machine damage and to prolong life time, please check the following items everyday.
Items
Checking content
Treatment
Power supply
Check if power supply meets the
requirement and whether there is
lack-phase.
Treat it as nameplate explains.
Surroundings
Check whether it meets the environment
requirement.
Make sure the problem and solve it.
Cooling system
Check whether the inverter or the motor
heat or change color abnormally and
cooling fan working state.
Check whether it overload. Tighten
screw. Check whether cooling fan is
dirty or stall rotate.
Motor
Check if there is abnormal vibration or
noise.
Tighten machine and electric
connection and lubricate the machine
components.
Load
Check whether output current is over the
rated value of the motor or the inverter
and has lasted for a period.
Make sure whether it overload and
whether the machine model is right.
●
Periodic overhaul
Under normal state, one overhaul every 3 or 4 months is ok. Please confirm the actual overhaul period according to
the machine use condition and work circumstance while using the machine.
Items
Checking content
Treatment
Whole
Check insulated resistance;
Check circumstance.
Tighten and change bad component;
Clear and improve circumstance.
Electric connection
●
Check whether the wire and connector
color changes, whether there is
disrepair, crack color change or aging
in insulated layer.
●
Check whether the connect terminals
are frayed, damaged or loose.
●
Earth checking.
●
Change bad wires.
●
Fasten terminals and change bad
terminals.
●
Measure earth resistance and fasten
earth terminals.
Mechanical
connection
●
Check if there is abnormal vibration or
noise or something is loose.
●
Tighten, lubricate and change the bad
components.
semi-conductive
component
●
Check whether there is dust or
rubbish.
●
If there is obvious out change
●
Clean operation environment
●
Change damaged component
