Great Plains NTA2007 Operator Manual - Manual (Page 81)

Great Plains Manufacturing, Inc. Table of Contents Index Adjustments 77
2012-01-05 Table of Contents Index 166-372M
Setting Variable Rate Gearbox
Refer to Figure 60
The variable rate gearbox lets you infinitely vary meter
drive speed to attain a wide range of seeding rates. The
ratio of gearbox input speed to output speed is controlled
by the position of a gearbox control arm. The control arm
has an indicator
that points to a scale marked in
degrees. The Seed Rate Charts and Fertilizer Rate
charts show the rate for each degree of the control arm
rotation.
• Manual: On the standard NTA607 and NTA2007 drill,
the control arm is manually positioned with a crank .
The initial setting is based on the seed rate chart, and
refined via calibration.
• Servo: With the optional Variable Rate Kit, the control
arm is positioned by a linear actuator . The setting is
commanded by the seed monitor, based on the rate
entered on the seed monitor console, and the current
Calibration Constant. The initial “Cal. Const.” is found
in the seed rate charts, and refined via calibration.
Manual Rate Setting
1.
Consult the seed rate chart for your crop, flute stars
and rate Range. Note the gearbox setting.
2. Remove the hairpin cotter securing the gearbox
adjustment crank.
3. Rotate crank until the control arm indicator points to
the scale setting that matches the rate from the seed
rate chart or determined by calibration.
4. Re-insert the hairpin cotter.
Variable Rate (Servo) Rate Setting
1.
Consult the seed rate chart for your crop, flute stars
and rate Range. Note the “Cal. Const.”
2. Enter the seed rate chart Calibration Constant on the
seed monitor (for the Channel associated with the
hopper and gearbox). If you have calibrated this
seed, use the recorded Cal. Const. developed from
that calibration.
3. Enter the desired material rate on the seed monitor
(for the Channel associated with the hopper and
gearbox).
Note: The variable rate gearbox operates optimally
between 30 and 70. If a seed has charts for both
HIGH Range and LOW Range, the most
consistent results are obtained when the gearbox
control arm is set between 30 and 70. Settings
below 20 degrees are not recommended. When
the control arm is set above 70 degrees, large
movements of the arm result in small changes in
seeding rate.
Note: If you will be metering the same material from both
bins at the same time, use the Seed Rate Chart
entry for half the desired application rate. Do not
use a half scale setting - the effect of the variable
rate gearbox control arm is not linear - a half scale
setting is usually not half the rate.
Note: The hand crank is present on both manual drills,
and (servo) drills with the Variable Rate kit. On
servo drills, the crank is disconnected from the
control arm. To revert to manual control, move the
coupler pin
from the servo control arm to the
manual control arm.
Figure 60
Variable Rate Gearboxes
31180
5
3
4
1
2
5
1
2
4