drilled reference disc (only fitted models)
FIG. 20
5.4AXIAL ROTOR
Generally the new models of rotors are fitted with 7 vanes made of aluminium or nylon + fibreglass and the vanes have a variable inclination from 20° to 40° with step adjustment by 5° (in some cases there are drilled reference discs)
FIG. 20.
The angular movement of all of the vanes, if done correctly, doesn’t change the dynamic balance of the blower group.
To change the inclination of the vanes (as standard this is set at 35°) proceed as follows:
a)Remove the protective grill.
b)Unscrew screws A that hold the spinner (central cover), each vane has two blocking screws B at the side, one on the right and one on the left. Unscrew the two screws enough to turn the vane the degrees necessary (replace the drilled discs when fitted). To make the adjustment easier, there are reference notches on blocking element C.
c)After you have positioned the vane, perform the same operation on the next one and screw the screws of the first in enough to block it in place.
d)Repeat the operation on all the vanes and after you’ve checked that all have the same angle, reassemble the spinner and the protective grill.
The fan is balanced dynamically; the different numbers of washers under the screws blocking the vanes are for balancing.
You shouldn’t change the position of the washers or add or remove any. Only tighten down the screws with moderate force as they have an aluminium thread.
5.5CLUTCH
Big aluminium and nylon blowers have a centrifugal type clutch that makes it possible to engage the fan rotor gradually.
This prevents jerky starts, due to the inertia of the fan rotor, which can have a negative effect on the transmission.
For the centrifugal clutch to work properly the speed of the
Generally clutches with shoes/plates made of sintered material with a high coefficient of friction are fitted, on some low power models rubber clutches may be fitted.
5.6CANNON BLOWER GROUP
The cannon blower group is equipped with a multiplier similar to the normal axial blower groups and all of its operating characteristics are the same. The main difference with respect to the axial blower groups is that the centrifugal fan rotor is made of galvanised steel, the fan rotors in this type are fixed and can’t be adjusted, for the clutch see the previous paragraph. This fan rotor can usually produce a delivery which is much higher with a very high speed airflow.
The cannon fan is mounted on a thrust block that can be adjusted by hand by unscrewing the relevant locking screw. This adjustment must be done with the fan rotor stopped because the high speed of the air make the movement of the fan dangerous.
5.6.1 MANUALLY INCLINABILE HEAD
The cannon blower group can be equipped with a pivoting head (max inclination 180°) adjustable by hand.
5.6.2 HYDRAULIC DRIVEN HEADS
On request hydraulic pivoting (inclination 90° roughly) and rotating (max rotation 270°) heads are available.
5.6.3 HYDRAULIC DRIVES
The cannon fans can be equipped with hydraulic drives: with the cylinder fitted directly (30° inclination roughly) or a motor with a pinion and chain (180° inclination roughly).
18unigreen
