Checking seed cup rate, Calibration equations – Great Plains 2525F Material Rate User Manual
Page 12

Great Plains Mfg., Inc.
10
118-232B
03/22/2007
Checking Seed Cup Rate
The seed charts are based on cleaned seed and origi-
nal factory-supplied tires. Factors including foreign
material, seed treatment, seed size, seed weight, field
conditions and tire pressure will affect seeding rate. Set
and check the seeding rate, then readjust the rate as
necessary.
1.
Record the weight of an empty container large
enough to hold seed for one acre.
2.
Place several pounds of seed over three seed cups
on an outside end of the drill box.
Note: If drill box is full, shut off seed cup doors for rows
not being measured.
3.
Raise drill off ground.
4.
Turn gauge wheel a few turns to fill seed cups with
seed and until seed drops to ground from all three
cups.
5.
Place a container under the three rows to gather
seed as it is metered.
6.
Using the chart on the next page, select your row
spacing and determine the correct number of revo-
lutions per acre. Turn drive gauge wheel the
selected revolutions for your row spacing. Check in
box to make sure seed tubes have plenty of seed
covering them.
7.
Weigh measured seed. Subtract initial weight of
empty container. Divide by three for the amount
metered by each cup, then multiply by the number
of rows for the pounds-per-acre seeding rate.
8.
If seeding rate is substantially different than desired:
• Re-check Drive Type required and actual
sprocket combination mounted.
• Re-check Seed Cup Handle setting required and
actual setting made.
• Re-check seed cup door setting.
• Check for seed cup malfunction.
• Check that all three rows are getting seed.
• Refer to Troubleshooting in the operator’s man-
ual.
9.
If seeding rate is only slightly different than desired,
check items in step 8, and if no trouble found, adjust
seed rate handle to next higher or lower setting.
Verify adjustment.
10. Repeat calibration for other side of drill.
Calibration Equations
MeasuredSeed EmptyContainer
–
3 NumberOfRows
(
)
----------------------------------------------------------------------------------
PoundsPerCup
=
PoundsPerCup NumberOfOpeners
×
PoundsPerAcre
=