Operating instructions

Great Plains Manufacturing, Inc. Table of Contents Index Adjustments 25
2013-03-25 Table of Contents Index 403-362M
Meter Calibration
The fertilizer rate charts are based on a representative
11-52-0 dry granular fertilizer. Many factors affect meter
rates including fertilizer density, granularity, texture,
adhesion, humidity and field conditions.
Great Plains recommends calibrating for the exact
material being applied. Calibration determines the kg/ha
(or lbs/ac) of the meter at the current variable rate
gearbox setting for your particular fertilizer.
Calibration Procedure
Calibration consists of:
• metering material for a simulated distance (area), by
manually cranking the ground drive system,
• measuring the sample weight generated, computing
the rate, and, if not the rate desired,
• adjusting the gearbox setting to produce a rate closer
to the target rate, then;
• re-sampling to verify the adjustment.
There are two ways to collect the sample:
a. Fan On / Row Sample (page 26)
Place collection containers under each fertilizer row
applicator (calibration door closed).
b. Fan Off / Meter Sample (page 27)
Place a tarp under the fertilizer meter with the
calibration door open.
Either method relies on manual operation of the fertilizer
ground drive system and meter. You may operate the
drive by turning the ground drive wheel itself, or use the
supplied 403-414H crank to turn the jackshaft at the
ground drive arm pivot.
Initial Calibration Steps
1. Set the final gear Range and variable rate gearbox
adjuster (from the charts on page 64 or 65, or
previous calibrations of similar material).
2. Hitch planter to tractor capable of operating the
planter. (See 401-406M or 401-571M Operator
manual.)
3. Close the slide gate on the seed hopper (page 14).
4. Raise the planter. Install transport locks. (See
401-406M or 401-571M Operator manual.)
5. Load enough fertilizer for at least
1
⁄
10
hectare (or
1
⁄
10
acre) plus an extra 35 to 45 kg (75 to 100 lbs)
(page 12).
Refer to Figure 11
6. Attach the 403-414H calibration crank to the left
end of the fertilizer ground drive arm pivot. You can
use the hairpin cotter from the gearbox adjuster
crank to secure the calibration crank to the shaft.
Sampling Error Risk:
Do not leave fertilizer hopper lid open. Low pressure above
fertilizer skews results. Perform calibration with lid tightly
closed, as for normal field operations.
Revolutions for Sample Size
Note: A cranking speed of 1 revolution per second
(60 rpm) simulates a field speed of 9 kph.
Note: For a more accurate calibration, crank for a full
hectare or acre. Make sure there is enough
material in the hopper.
Material Rate Risk:
Check consumption rates in the field. One variable factor that
calibration cannot compensate for is the effective rolling
radius of the ground wheel in unusually soft or hard ground.
Figure 11
Calibration Cranking
31000
Sample Revolutions of:
Size Crank Wheel
1/10th Hectare 4.52 5.24
1/10th Acre 11.16 12.95
1 Hectare 45.2 52.4
1 Acre 111.6 129.5
31104
1
2
1
2