Belarus 80.1 Operation Manual page 153

- "FDA engages and disengages automatically" – middle position. In this mode auto-
matic engagement and disengagement of the FDA by means of the free travel coupling
occurs depending on the rear wheels slipping. It is provided when the toothed crown of in-
ner ring 7 (figure 3.10.9) connects to the toothed crown of coupling 13. In this case stop 5
(figure 3.10.11) of link 4 is in the middle slot of strut 6.
When the tractor moves forward without slipping inner ring 7 (figure 3.10.9) of the free
travel coupling, rigidly connected to the front wheels, has rotation frequency higher than
the outer ring. In this case wedging of the rollers does not occur, torque is not transmitted
to the FDA.
If the rear wheels slip more than the set value rotation frequency of the inner ring de-
creases until it is equal to rotation frequency of the outer ring. In this case the coupling rollers
wedge and join the two rings in one piece, to ensure that torque is transmitted to the FDA.
Use this mode for various field works.
- "FDA positively engaged" – upper most position.
Positive engagement is carried out by toothed coupling 13, which while moving over
shaft splines, meshes with inner teeth of gear 9 and connecting it directly to shaft 5, blocks
the free travel coupling. In case of positive engagement stop 5 (figure 3.10.11) of link 4 is
in the upper slot of strut 6. Use this mode only in cases of the rear wheels constant slip-
ping and when reversing, when engagement of the FDA is required.
1 – pin; 2 – fork; 3 – locknut; 4 – link; 5 – stop; 6 – strut; 7 – handle; 8 – transfer box;
9 – lever.
Figure 3.10.11 – Control of the FDA drive transfer box on tractor "BELARUS- 82.1"
with canopy frame or canopy base on the basis of a small cabin
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80-0000010B OM