ABB DCT880, Service Manual

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Annual preventive maintenance
The following actions have to take place:
− Check the cooling fans of units T1 … T5.
The lifetime of the cooling fan is about 40,000 to 70,000 hours depending on the unit size, the usage of
the thyristor power controller and the environmental conditions (e.g. temperature). Fan failure can be
predicted by means of increasing noise from its bearings and a gradual rise of the heatsink temperature.
If the thyristor power controller operates in a critical part of the process it is recommended to replace the
fan once the above-mentioned symptoms appear.
− Check the door air filters.
− Clocked up filters prevent proper cooling
of the thyristor power controller. Wash
dirty filters with water (60°C) and
detergent.
−
Check for dust, corrosion and temperature
inside the module / cabinet. The thyristor
power controller will run into
overtemperature faults if the heatsinks are
not clean.
− Pre-clean the heatsinks using an ESD
vacuum cleaner then use compressed air
to remove the dust from the heatsinks (the
airflow must be from bottom to top). Fan
rotation caused by the compressed air
must be stopped in order to prevent
damage.
− Use an ESD vacuum cleaner to clean the
dust from the air inlet, air outlet, the
interior of the cabinet and the electronic
boards.
−
Any signs of corrosion, especially at
ground components, must be removed.
− Check the quality of the supply voltage (e.g. deviation from nominal voltage value, …).
Preventive Maintenance
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