Last time we introduced the Pulley Speed Ratio Formula, a Formula, one which oversees how friction comes into play between belts and pulleys, the . It’s a Euler-Eytelwein Formuladeveloped by two pioneers of engineering introduced in an earlier blog, Formula Leonhard Euler and Johann Albert Eytelwein.Here again is the Pulley Speed Ratio Formula,
N × _{1} = D_{2}N_{2}where, D the diameter of the driven pulley. The pulleys’ rotational speeds are represented by _{2}N and _{1}N_{2}.This equation works when it operates under the assumption that friction between the belt and pulleys is, like Goldilock’s preferred bed, “just so.” Meaning, friction present is high enough so the belt doesn’t slip, yet loose enough so as not to bring the performance of a rotating piece of machinery to a grinding halt. Ideally, you want no slippage between belt and pulleys, but the only way for that to happen is if you have perfect friction between their surfaces—something that will never happen because there’s always some degree of slippage. So how do we design a pulley-belt system to maximize friction and minimize slip? Before we get into that, we must first gain an understanding of how friction comes into play between belts and pulleys. To do so we’ll use the famous
where, T are belt tensions on either side of a pulley._{2} We’ll continue our exploration of the Copyright 2017 – Philip J. O’Keefe, PE Engineering Expert Witness Blog ____________________________________ |