Great Plains 2420 Material Rate - Manual (Page 3)

3/1/2004 118-706B
Great Plains Mfg., Inc. 3
Seeding Rate
Calibrating the seeding rate requires four steps:
• adjusting drive sprockets,
• setting seed-rate handle,
• positioning seed-cup doors, and
• checking seeding rate.
Refer to the seed-rate charts on page 5. These charts
list proper sprocket sizes and seed-rate-handle settings
for various seeds and seeding rates.
The seed-rate charts are based on cleaned, untreated
seed of average size and test weight. The charts are
based on 11L x 15, rib implement tires. Many factors will
affect seeding rates including foreign material, seed
treatment, seed size, seed weight, field conditions and
tire pressure. You likely will need to make minor adjust-
ments. Set and check the seeding rate, then readjust the
rate as necessary.
Before setting the seeding rate, rotate the gauge wheels.
Check that seed cups and drive are working properly
and free from foreign material.
Adjust Drive Sprockets
Refer to Figure 1
Use drive sprockets for the drive type for your desired
seeding rate.
For correct drive type, refer to seed-rate charts begin-
ning on page 5. The charts lists drive types as 1, 2, 3 or
4. Refer to the table on the right for correct-sized sprock-
et for each drive type.
Refer to Figure 2
To change drive sprockets, loosen idler plate (1) and re-
move drive chain (2). Remove lynch pins from shafts and
rearrange driver (3) and driven (4) sprockets as
necessary.
Reroute drive chain over sprockets and idlers. Be sure
chain is installed with the chain connector link retainer
towards the centerline and the clip opening (split end)
faces the opposite way of the chain travel. Move idlers
into chain so chain has 1/4-inch slack in its longest span.
Tighten idlers.
Set same drive type on both drill sections.
17669
17617
Drive Type Driver Driven Speed
Type 1 15 Tooth 47 Tooth Slowest
Type 2 24 Tooth 36 Tooth Two Times Faster
Than Type 1
Type 3 24 Tooth 24 Tooth Three Times Faster
Than Type 1
Type 4 24 Tooth 15 Tooth Five Times Faster
Than Type 1
Figure 1
Drive Sprockets
Figure 2