Great Plains NTA2000D Operator Manual - Manual (Page 38)

36 NTA 2000D 148-632M 9/13/2006
Great Plains Mfg., Inc.
19769
19770
19768
Checking the Seeding Rate
The following procedure should be followed to calibrate
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 knowledge of
field size.
• Errors in metering which are affected by seed treat-
ments, 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 48, for the
seed to be sown. Set to the “High” or “Low” speed, ad-
just the flaps below the feed rollers to the required po-
sition and adjust the variator lever to the setting
indicated on the guide chart to give the target 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 110 lbs. (50 kg) 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 Var-
iator and rotate clockwise to “prime” the feed mecha-
nism. 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 41 turns. (For extra accuracy
it is recommended to carry out a Calibrations for Num-
ber of Turns, described on the next page).
10. Weigh the seed collected from both trays in pounds.
Use an accurate set of scales. This amount is equiva-
lent to 1/10th acre.
Seeding Rate (lb/ac)=Weight Collected (lb) x 10
19924
a
b
Figure 49
Venturi Unit
Figure 51
Calibration Tray
Figure 52
Calibration Crank Handle
Figure 50
Venturi Unit