ABE TUTORIALS

AGRICULTURAL AND BIOSYSTEMS ENGINEERING

PROBLEM:
ESTIMATE THE HORSEPOWER REQUIRED TO LIFT A 4545 KG LOAD BY MEANS OF A CABLE WRAPPED AROUND THE DRUM OF A HOIST. THE DIAMETER OF THE DRUM IS 127 CM AND IT ROTATES AT 30 RPM. (NEGLECT THE WEIGHT OF THE CABLE)

Select the required horsepower:

a. 18.9
b. 37.9
c. 238
d. 476
e. nota

Click to View Solution

Step 1: Calculate the Force (Tension) required.
Force = Mass × Gravity
Force = 4545 kg × 9.81 m/s² = 44,586.45 N

Step 2: Calculate the linear lifting speed (Velocity).
Velocity = π × Diameter × (RPM / 60)
Velocity = 3.1416 × 1.27 m × (30 / 60) ≈ 1.995 m/s

Step 3: Calculate Power in Watts and convert to Horsepower.
Power (Watts) = Force × Velocity
Power = 44,586.45 N × 1.995 m/s ≈ 88,950 W
Power (hp) = 88,950 W / 746 ≈ 119.2 hp

Result: e. nota (None of the above)