6620, 7720 and 8820 Combines With Variable-Belt-Drive Feeder House

The corn head drive speed is varied by changing the speed of the lower feeder house shaft. Lower feeder house shaft speed is changed with the variable speed control lever located on the steering column.

Shaft speed of variable drive equipped feeder house ranges from approximately 490 to 740 RPM.

Use the following table as a guide in matching corn head speed to combine travel speed:

Approximate
Combine Travel Speed		 Approximate
Lower Feeder House
Shaft Speed
 
less than: 4.0 km/h (2.5 mph) 490 rpm
  4.8 km/h (3.0 mph) 575 rpm
  5.6 km/h (3.5 mph) 660 rpm
greater than: 6.4 km/h (4.0 mph) 740 rpm

 

The range of corn head operating speeds can be changed by the position of row unit drive sprockets.

Transverse Shaft
Driver Sprocket		 Row Unit
Driven Sprocket		 %
Increase
27T 32T none
27T 27T 25
32T 32T 25
32T 27T 55

 

The higher speed positions of these sprockets are used only when travel speeds consistently exceed 6.4 km/h (4.0 mph) or for more aggressive snapping action.

H35403

MH81805,000070E -19-17MAR05-1/1