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21
Pt. No. 67304
Issue 1217
Calibration Deviations
Deviations Between the Calibration Test and the Actual
Seed Rate
The most frequent cause for changes between the calibration test and
the seed rate lies in the flowing properties of seed during sowing. These
changes in properties generally result from reactions of the dressing
agents to temperature, humidity or abrasion. These changes will become
even more obvious when the bottom flaps are incorrectly set. If the setting
of these flaps leaves too large a gap an uncontrollable additional flow
of seed can occur during seeding; especially when assisted by the drill
bouncing, a condition not simulated while conducting the calibration tests.
For this reason the basic setting of the bottom flaps should be checked at
regular intervals. For more details refer P 30, Fig 39.
Residues from the seed dressing on the bottom flaps and metering wheels
can also influence the flowing properties of the seed and thus the seed
rate. In such cases a balance will occur only after a period of time and it is
recommended to repeat the calibration test to confirm the seed rate after
2-3 seedbox fillings, nominally when the seed box is half empty.
Only then will a balance occur and the seed rate will stabilise.
Wheel Slip Deviations
It is always possible with rubber tyred drills in extreme ground conditions
to get wheel slip. Not normally a problem with cleated type tyres in good
condition, but more so in the arable situation with the less agressive
tread patterns normally found on this type of machine. The result; large
differences between the calibration test and the actual sowing rate,
obviously less seed deposited than required. The number of crank turns
indicated in the table on P19 is correct in most circumstances other
than those mentioned above; however soft seed beds and a fully laden
machine can affect the rolling circumference of the tyre.
Should you require to check this due to some unforeseen circumstances
proceed as follows...
Measure an area of 250 m
2
(1/40 Hectare) - this corresponds to a machine
travel of... Refer Fig 22.
For this calibration test place the crank handle over the hexagonal drive
dog on the gearbox input shaft. Now move the machine slowly forward
over the measured distance, counting the number of turns of the crank
handle as you go. Using this number of crank turns repeat the calibration.
Machine
Row
Sowing
Travel
Size Spacing Width
(m)
Distance
15
Run
150 2.25
111m
17
Run
130 2.21
113m
19
Run
150 2.85
87.5m
21
Run
133 2.84
88m
23
Run
150 3.45
72.5m
26
Run
130 3.38
72.5m
fig 22
Содержание Enviro 740
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Страница 26: ...24 Enviro Seed Drill Calibration Notes ...
Страница 33: ...31 Pt No 67304 Issue 1217 Enviro Seed Drill Maintenance Notes ...
Страница 34: ...32 Enviro Seed Drill Maintenance Notes ...
Страница 44: ...42 5 6 Enviro Seed Drill Wiring Lighting Kit ...
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Страница 70: ...68 1 1 2 3 3 4 4 5 6 6 7 7 8 8 9 9 10 10 11 12 15 Enviro Seed Drill Seeder Assembly ...
Страница 72: ...70 Enviro Seed Drill Operator Notes ...