Cod. 985719 – 00 / July 2004
13
Remarks:
1. If F< F', a higher belt tension is required. If F>F", the belts are too tight
2. During the running-in period of the fan belts an early decrease in tension takes place. It is therefore necessary at the
initial assembly to tension the belts 1,3 times higher than the "f" arrow shown in the tables. Belt tensions should be
checked regularly and always after the first eight working hours.
4.3. SAFETY ACCESSORIES
Some safety devices are already included in the equipment as standard components while some are offered as optional
items. It is customer’s care to control that the machine where the fan is installed is in accordance with the local safety
norms.
4.3.1. Protection of moving components
All fans have moving parts, and require protection against contact.
Centrifugal fans are usually connected to ductwork affording protection against contact with moving parts. In the case of
free inlet or discharge, protection must be provided by means of proper guards or grilles.
In addition to inlet and outlet protection, it is necessary to provide protection from the fan shaft, belts and pulleys and all
other external moving parts by means of suitable protection guards (REF. UNI 9219).
4.3.2. Electrical insulation
Each fan must be protected with a local isolator.
Many fans are automatically controlled or controlled by remote systems, and therefore to ensure complete safety it is
necessary to provide a power interlock close to the fan, in order to enable maintenance staff to isolate the fan
independently from the main control system.
4.4. INSPECTION AFTER INSTALLATION
Make sure that inside the housing or wheel there are no foreign objects which can be ejected during start up (for example
screws fallen during mounting etc).
• Check if the shaft is bent or misaligned (for fans with couplings)
• Rotate the shaft and verify that the impeller can move freely and that it does not come in contact with the inlet cone
• The screws must be tightened
• The bearings must be locked correctly
• The impeller must not move on the shaft. The set screw of the hub must be tightened
4.5. STARTING THE FAN
• Switch on the power
• verify that the impeller rotates in the direction of the arrow moulded on
the housing or indicated in the label
• check if vibration and noise are normal
• tension and absorbed power values must be in accordance with the
data of the fan/motor rating plate
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