We’ve been working our way towards developing values for variables in our example pulley-belt assembly, and last time we calculated the velocity of the belt in that assembly to be 237.99 feet per minute. But before we can go on to calculate the belt’s loose side tension, T, we’ll need to discuss _{1} specifically how to convert unit conversion,.horsepower into foot-pounds per second Our working formula for this demonstration is the formula for mechanical power,
V (1) By engineering convention mechanical power is normally measured in units of V, it was measured in units of feet per minute, not per second. To further complicate things, the difference in belt tensions, P being expressed in , not the required per foot-pounds per minutesecond, because we are multiplying feet per minute by pounds. That’s a whole lot of unit changing within a single equation, which makes for an awkward situation. To smooth things out we’ll have to do some converting of units. We’ll start by dividing
The power in our belt was previously given as 4 so it can be used in equation (1).foot-pounds per second
One , which makes the amount of power, foot-pounds per secondP, in our pulley-belt assembly equal to 2,200 .foot-pounds per second Units converted, we can now insert the values for 2,200 foot pounds per second = ( Next time we’ll use this relationship to develop values for T, the belt’s tight and loose side tensions._{2}Copyright 2017 – Philip J. O’Keefe, PE Engineering Expert Witness Blog ____________________________________ |