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Techno Linear Motion Catalog 10 Technical Information Duty cycle calculation The RMS (root mean squared) value of a load is one of the quantities often used to size PT components.                      _____________________                L12t1 + L22t2 + ... + Ln2tn LRMS = 3 –––––––––––––––––––– (11)                         t1 + t2 + ... tn where: LRMS  = RMS value of the load which can be in any unit — hp, amp, etc. L1 = Load during time period 1 L2 = Load during time period 2, etc. t1 = Duration of time period 1 t2 = Duration of time period 2, etc. Modulus of elasticity    PL E = ––––– (12)     ADd where: E   =  Modulus of elasticity (lb/in2) P   =  Axial load (lb) L    =  Length of object (in) A   =  Area of object (in2) Dd =  Increase in length resulting from axial load (in)   Hollow cylinder rotating about its own axis:          1 WK2 = ––– W (R12 + R22) (8)           2 where: WK2= Moment of inertia (lb•ft2) W = Weight of object (lb) R1 = Outside radius (ft) R2 = Inside radius (ft) Material in linear motion with a continuous fixed relation to a rotational speed, such as a conveyor system:                      V WKL 2 = W (–––––) 2 (9)                    2pN where: WKL2= Linear inertia (lb•ft2) W = Weight of material (lb) V = Linear velocity (fpm) N = Rotational speed of shaft (rpm) Reflected inertia of a load through a speed reduction means — gear, chain, or belt system:              WKL 2 WKR 2 = ––––– (10)                Rr 2 where: WKR2= Reflected inertia (lb•ft2) WKL2= Load inertia (lb•ft2) Rr = Reduction ratio Time L1 L2 L3 t1 3–––––––––––––––––          ––––––––––––3 t3 3–––––          –––3 3–––––––          –––––––3 t2 • • • Axial Radial    Tangential Circumferential                   R1 R2