Great Plains NTA2000 Operator Manual - Manual (Page 35)

33 2/2/2006 NTA 2000 148-561M
Great Plains Mfg., Inc.
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Checking the Seeding Rate
The following procedure should be followed to cali-
brate the drill for different seed types. Note that the
following factors may affect seeding accuracy:
• Errors in land area which are affected by wheel
slip, operator judgement and by inaccurate knowl-
edge of field size.
• Errors in metering which are affected by seed
treatments, seed size, variety, moisture content
and seed bulk density.
To calibrate the drill, an accurate set of scales will be
required. Other equipment is supplied with the drill and
includes calibration trays and handle.
Procedure
Refer to Figure 49
1. Release the two black plastic lock screws above
each venturi unit by loosening, sliding the knob up
and re-tightening.
2. Push the left and right venturi units forward to clear
the feed units.
Refer to Figure 50
3. Remove calibration tray (a) from storage position
above the feed rollers by loosening center knob (b)
and sliding lock tab down.
Refer to Figure 51
4. Position the calibration trays under the feed rollers.
5. Refer to the “Seed Rate Charts,” page 44, for the
seed to be sown. Set to the “High” or “Low” speed,
adjust the flaps below the feed rollers to the re-
quired position and adjust the variator lever to the
setting indicated on the guide chart to give the tar-
get rate.
6. Ensure that the drill is not in a tramlining bout so
that all the feed rollers turn when the seed shaft is
rotating.
7. Fill the hopper with at least 50 kg (110 lbs) of seed
to ensure that all the feed rollers are covered
throughout the test.
Refer to Figure 52
8. Position the crank handle on the input point of the
Variator and rotate clockwise to “prime” the feed
mechanism. It is important to turn the handle at
least 50 turns before calibrating to ensure seed is
flowing correctly through the system. Empty the
calibration trays before carrying out a full test.
9. Rotate the crank handle 103 turns. (For extra ac-
curacy it is recommended to carry out a Calibra-
tions for Number of Turns, described on the next
page).
10. Weigh the seed collected from both trays in kilo-
grams. Use an accurate set of scales. This amount
is equivalent to 1/10th hectare.
Seeding Rate (kg/ha)=Weight Collected (kg) x 10
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a
b
Figure 49
Venturi Unit
Figure 51
Calibration Tray
Figure 52
Calibration Crank Handle
Figure 50
Venturi Unit