Calculating Horsepower For an Incline Drag Conveyor

Use the following formula to estimate required horsepower for an incline drag (en-masse) conveyor. 


1.  Determine overall ground length of drag conveyor
2. Multiply LENGTH X BUSHELS PER HOUR
3.  Divide results by 55,000 - Write this total down.

4.  Determine the discharge height in feet and multiply by the bushels per hour desired.
5.  Divide the result by 26,500. - Write this total down.

6.  If a curve section is used, divide the BPH desired by 1325.
(If no curve section is used, ignore step 6.)
7.  Add the sums of the individual horsepowers to find the total horsepower.

The above formula has been found to be adequate for products such as shelled corn and soybeans.  HEAVIER PRODUCTS MAY REQUIRE ADDITIONAL HORSEPOWER.

Formula example:
Overall length of the example conveyor is 50 feet.  The discharge height of the conveyor is 7 feet from the bottom of the conveyor.  There is a curve section used.

50 feet x 5000 bushels per hour = 250,000 divided by 55,000 = 4.5455
7 foot conveyor discharge height x 5000 bushels per hour = 35,000 divided by 26,500 = 1.3208
5000 bushels per hour divided by 1325 (curve section factor) = 3.7736
Add 4.5455 + 1.3208 + 3.7736 = 9.6399 total required horsepower  (Round up to the nearest motor means this conveyor requires a 10 HP electric motor.)

Calculating Required Horsepower For a Horizontal Drag Conveyor

Calculating Required Horsepower For a Horizontal Drag Conveyor (En-Masse Conveyor):
There are several ways to calculate horsepower for a drag chain conveyor in a grain handling application, however, I have found this shortcut for figuring horsepower for a horizontal drag conveyor to be one of the easiest to use.
1.  Determine overall length of drag conveyor
2. Multiply LENGTH X BUSHELS PER HOUR
3.  Divide results by 55,000

The above formula has been found to be adequate for products such as shelled corn and soybeans.  HEAVIER PRODUCTS MAY REQUIRE ADDITIONAL HORSEPOWER.

Example:
50 foot overall length conveyor handling corn at 10,000 bushels per hour.
50 x 10,000 = 500,000
500,000 divided by 55,000 = 9.0909
Round up to nearest motor size means you would use a 10 horsepower electric motor.

Calculating Horsepower for a Bucket Elevator

HORSEPOWER FORMULA FOR BUCKET ELEVATORS:

1. DISCHARGE HEIGHT IN FEET X BUSHELS PER HOUR,

Divided by 33,000 gives BARE HORSEPOWER

2. Multiply Bare Horsepower x 1.25 (safety factor) to get DESIGN

HORSEPOWER.

3. This calculation is based on grain weighing 60# per bushel.

ALTERNATE HORSEPOWER FORMULA:

1. Multiply DISCHARGE HEIGHT IN FEET X POUNDS OF MATERIAL

RAISED IN 1 MINUTE. Divided by 33,000 gives BARE HORSEPOWER.

2. Multiply Bare Horsepower by 1.25 (Safety Factor) for DESIGN

HORSEPOWER.

Calculate Bucket Elevator Capacity

TO FIND BUCKET ELEVATOR LEG CAPACITY:

1. DETERMINE BELT SPEED IN FEET PER MINUTE

a. Motor RPM x motor pulley diameter, divided by driven pulley diameter = Input shaft speed to drive.

b. Divide Input shaft speed by Drive reduction ratio (15:1, 25:1, etc.) This gives the head shaft RPM.

c. Multiply the head shaft RPM x head pulley diameter in feet, x

3.1416. This gives the Belt speed in feet per minute.

2. FIND THE NUMBER OF CUPS FILLED IN ONE MINUTE:

a. Multiply feet per minute of belt speed x 12”, divided by cup spacing in inches.

b. Find cup capacity from Manufacturer’s chart in cubic feet.

Use water level + 10% or 75% of gross cup capacity.

c. Multiply cups filled per minute x cup capacity in cubic ft. This gives capacity of leg in one minute. Multiply result x 60 minutes

for hourly capacity in cubic feet.

d. For Bushels per hour, multiply cubic ft. per hour x .8