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Pull-Planner™ 3000 tutorial #3 tackles Jam Ratio. First, what is jamming? Jamming is a phenomenon that happens only in pulls of three cables into conduit with at least one bend. Picture this: three cables scrunched comfortably in a triangular configuration scooting down the conduit until they encounter a bend. The bend, however, forces the three cables to splay out into a side-by-side configuration. If the combined width of the three cables is big enough, the cables will wedge against the conduit walls, stopping the pull cold. The forces required to pull through a jam will only damage the cables, conduit, or both. As any good coon hound will tell you, jamming is not a good thing. Jam ratio is an equation: conduit ID divided by average cable OD. Example: three 1-inch cables in a 3-inch conduit yields a 3.0 jam ratio. Jamming only occurs within a jam ratio range of 2.6 to 3.1. Why? If the three cables are small enough in relation to the conduit, they can't wedge. If they're big enough, they can't be forced out of their triad. The PP3KW automatically averages cable OD, calculates the jam ratio, and rewards the user with a conclusion that jamming is either "not possible," "not probable," or "is likely." Now isn't that nice? For more information (with pictures and charts!), visit our Jam Ratio Research Paper. It's highly technical, but surprisingly one of our most popular webpages. Yet another reason customers flock to Polywater--no other competitor offers anything even close to this. |
