MVA 02 rev 5 - December 2017
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CAUTION:
To construct the entire transmission and/or install the motor only, the user and/or installer
must always request the transmission specifications document. It is absolutely prohibited to
construct transmissions with the use of couplings, drive belts and pulleys of types other than
those indicated by the transmission specifications document.
CAUTION:
If no inverter is used for gradual starting of the fan, it is absolutely prohibited to use toothed
pulleys, as these can cause irreversible damage to fan structures. Consult the FVI Technical
Office.
CAUTION:
Conditions of overspeed can be caused by drive system faults on fans with direct
transmissions.
In the case of directly-coupled fans of high power, starting is a moment of particular stress for rotating
mechanical organs.
CAUTION:
Above 11 kW, a gradual starting procedure must be used, to avoid overloading the
transmission system and the impeller, with the consequent risk of breakages in these
components.
In the case of fans supplied without an electric motor, incorrect electrical connections to the motor or the
wrong motor choice could be the cause of operation at speeds in excess of the original design speed, given
that the rotation speed of an asynchronous motor depends on the frequency and the number of poles.
CAUTION:
Fans are designed to be powered with a supply frequency of 50 Hz.
The manufacturer must always be contacted in the case of use of a supply frequency other
than the original design frequency. Do not proceed until authorized.
The use of a supply frequency different from the original design frequency affects all fan characteristics. The
modification of conditions of use requires a complete revision of the technical information sheet of the fan.
In the case of use at varying fan speeds or with frequent starting and stopping during operation, rotating
organs are subject to mechanical stresses that may affect their operative lifespan.
CAUTION:
In the case of fan operation with a variable speed cycle of less than 30 minutes, this cycle
must be submitted to approval by the FVI Technical Office, which will give its approval and
notify the consequent reduction of maintenance intervals and the fan lifespan.
