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15.8. FAN UNIT
Before any works (fault, maintenance, servicing) on the unit, and particularly before opening
inspection panels of the fan section and removing guards from live parts, make sure that:
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the device is properly disconnected from the power supply. This applies to both main and
auxiliary circuits,
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rotor is in standstill,
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fan is cooled down, and the temperature on its surface presents no risk of suffering a burn,
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fan is protected against an accidental start.
15.9. FANS
Fans are intended to transfer dust-free or slightly dusted air. They are not intended for use with
aggressive gases, vapours or highly-dusted air. Fan operation in non-compatible environment may
lead to damaging bearings, corrosion, unbalance of rotor and vibrations. For fan servicing check
whether:
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rotor rotates freely,
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is balanced and shows no run-out,
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rotor is securely mounted on the axle,
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rotor is not shifted against entry funnel,
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flexible connection (if present) is not damaged,
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all bolts securing the fan unit components are tightened.
Loss of rotor balance may be caused by:
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dust deposits on rotor blades,
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loss of additional balance weights,
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damage to rotor blades.
Inspect contaminations in the housing interior, rotor and motor once every 6 months, and if needed
clean:
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the housing interior with vacuum-cleaner,
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rotor with vacuum-cleaner or using wet cleaning with a mild detergent.
15.10. FANS MOTORS
Careful, regular maintenance and control of motor condition is necessary to find any incompatibilities
before major damages occur Before any works related to the motor or other motor equipment, and
particularly before removing guards provided for protection against contact with movable or live
parts, make sure that the motor is correctly disconnected from the power supply. Moreover, also
disconnect additional and auxiliary circuits. Follow the below safety rules:
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disconnect the power supply,
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use protection against accidental activation,
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check functionality of safe isolation of power supply,
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use guards on adjacent live parts.
All the above precautions should be kept until all maintenance works are not completed and the
motor is not fully assembled and ready to be started. For fan motor servicing check:
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whether defined specifications are met (power consumption, temperature of windings,
bearings),
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whether there are no grease leaks,
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whether the motor operates properly and noises coming from the motor and bearings do
not get louder,
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all mechanical and electrical connections for proper fixing,
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resistance of insulation of the windings,
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whether wires and insulations are in good condition and there are no discolourations.
All changes and incompatibilities should be removed immediately. Moreover:
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inspect whether the motor is properly mounted and mounting bolts are tightened,
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check whether the motor housing is not contaminated.
Excess contamination hampers the motor cooling, what in consequence may lead to overheating of
the motor windings and its damage. The motor can be dry cleaned with a brush or blown with dry
compressed air.
