Question

Points A scraper is operating on an earthen road and has penetration of 2.5 in. This scraper has an EVW of 90,000 lb and its GVW is 170,000 lb. The grade from cut to fill is 3%. Calculate the total resistance in both pounds and equivalent grade and also use Using the performance chart given on slide 32 (Numerical Example 1 Equipment Power) determine the speeds

Answer 1

Given that: EVW = 90,000 lb GVW = 170,000 lb = 17.11 tons Grade from cut to fill = 3% use conversation factor, 1 lb = 0.000453592 tonne rightarrow consider the rolling resistance, RR = 55 lb/tonne rightarrow Therefore, total rolling resistance, RR = 55877.11 RR = 4241.05 lb rightarrow For grade less than 10%, Grade resistance, GR = (20 l/ton) times (% grade) GR = (20 times 77.11) (3) GR = 4626.6 lb rightarrow calculate the total resistance, TR = RR + GR = 4241.05 + 4626.6 TR = 8867.65 lb rightarrow calculate the equivalent grade, GR = 55 lb/tonne/20 lb/tonne GR = 2.75%