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6.1 Before maintenance
by blocking the fan rotors. PM motors can generate high voltages when the motor axles rotate,
even though the power is disconnected.
6.2 Cleaning
Clean the fans at least quarterly. The intervals may have to be adjusted, dependent on the
operation and operational conditions. Corrosive and dust filled atmospheres typically shorten
the intervals. Please note that deposits of dust can be ignited by high surface temperatures and
constitute a safety risk.
6.3 Vibration levels
After installation and also in connection with regular
inspection and cleaning, the vibration levels must be
measured and be less than or equal to max. 6.3 mm/s.
Measure the levels at operational fan speed, radially at two
points with a 90° offset and at the free shaft end of the motor.
Fans that exceed the limits usually require cleaning or
balancing of the rotors. Alternatively, the causes must be
investigated and removed. Refer to ISO 14694.
For variable speed fans the vibration level limits are likely
to be exceeded at certain speeds. Continuous operation at
these speeds must be avoided.
6.4 Fan casings
The fan casings require no other maintenance than ordinary cleaning.
Check painted casings regularly and keep them in good condition.
6.5 Rotors
The rotors are carefully balanced and the rotor blades are set at precise angles in the production.
The rotors are thereby optimised for vibration free operation at the desired operation point with
regard to pressure, airflow and fan speed.
Novenco ZerAx axial fan types AZL-AZN-AZW – Installation and maintenance
Repair and maintenance of Novenco fans must be carried out by authorised personnel
and in accordance with Novenco instructions. Keep records signed by the competent
personnel for all services, tests and changes performed.
Switch off the power and disconnect the motor cable in the terminal box, before
beginning work on the rotor and motor.
For fans with PM motors, make sure the motor axles cannot rotate during service, e.g.
Fan vibration levels
depend on installation
type and fan speed.
Vibrations have significant effect
on fan life and efficiency.
Shut down fans with
vibration levels that
exceed 12.5 mm/s RMS.
15 of 30
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