Engineering Application and Web Tension Information Inertia: Shortcut Web Formulas: The tendency of matter to remain at rest or continue at a fixed velocity, unless it is affected by an outside force. The velocity can be linear or rotational. Example: Tension = 66 lb Velocity = 500 fpm Full Roll Dia = 36 inches Core Dia. = 9 inches Inertia = (WK2), where W = weight of object Web HP: K = distance from the axis of rotation Some inertia are: A. SOLID DISK (WK2) = 1/2W X R2 where R is Radius in feet B. CLUTCH GEARED TO LOAD Unwind Dissipation = WEB HP = 1HP (746 Watts) Rewind Dissipation = (DIAMETER RATIO - 1)(Web HP) C. W = Conveyor load in pounds V = Velocity in ft/min RPM = measured at clutch Relating Inertia to Torque: To determine the torque required to start or stop a load in a specified amount of time: Motor HP = (DIAMETER RATIO)(Web HP) Useful Conversions: GENERAL 1 meter = 100 centimeters = 1,000 millimeters 1 micron = 0.001 millimeter 1 kilogram = 1,000 grams 1 foot = 12 inches 1 mil = 0.001 inches 1 pound = 16 ounces LENGTH 1 foot = 0.3048 meters 1 inch = 2.54 centimeters FORCE 1 pound = 4.4482 newtons TORQUE 1 pound-foot = 1.3558 newton-meters 1 pound-foot = 0.13826 kilogram-meters 1 pound-inch = 0.1130 newton-meters VELOCITY 1 foot per minute = 0.3048 meters per minute POWER 1 horsepower = 745.7 watts INERTIA 1 pound-foot2 = 0.04214 kilogram-meter2 MATERIAL THICKNESS 1 mil = 25.4 microns TEMPERATURE C = 5/9 (degrees F-32) or F = 9/5 (degrees C) + 32 PRESSURE 1 pound per square inch = 6.89 kilopascals APPLICATION PROBLEMS OR QUESTIONS? CALL THE TENSION HOTLINE: 1-800-MAGPOWR 624-7697 www.magpowr.com MASS 1 pound = 0.4536 kilograms Engineering Application and Web Tension Information 3http://www.magpowr.com