Sofstep® Selection Rewind Tension Control Information required: Soft Stops/Controlled Deceleration Core dia. = 2 inches Information required: Full roll dia. = 8 inches RPM = 1000 RPM Tension* = 2 lbs Time to Stop Load = 4 secs. Velocity = 200 fpm Inertia** = 144 lb-in2 String and Pulley Method Affix a pulley to the shaft of a machine to be measured. Secure a string or cord to the outer surface of the pulley and wrap the cord around a few times. Tie the other end of the cord to a spring scale. Pull on the scale until the shaft turns. The force (in pounds) indicated on the scale, multiplied by the radius of the pulley (in inches) gives the torque in pound-inches. Rotating Inertia Input RPM = 400 RPM Torque Tension Roll Sofstep Brake Torque How to size: Sofstep Clutch Motor How to size: Information required: RPM = 800 RPM Inertia** = 18 lb-in2 Select brake model PSB-70 from specification chart. Time = .050 secs Overload Protection/Torque Limiting/Soft Start Frequency = 300 cycles/minute Motor Information required: Motor HP = 1 hp Shears Motor RPM = 900 RPM Torque Motor horsepower method: Sofstep Clutch/Brake Conveyor Indexing Wheel Slip RPM = Input RPM - Full Roll RPM = 400 - 95 = 305 RPM How to size: Slip Watts = .0118 xTorque (lb-in) x Slip RPM = .0118 x 8 x (305) = 29 Watts Torque Sofstep Clutch Select clutch model PSC-70 from quick selection chart *Note: If tension is unknown see section on calculating web tension. **Note: If inertia is unknown see section on calculating inertia. Torque 2 = Inertia (lb-in ) x RPM 3690 x time(s) = 18 x 800 = 78 lb-in 3690 x .05 Motor Watts = 2 How to size: Torque (lb-in) = HP x 63000 / RPM = 1 x 63000 = 70 lb-in 900 Select clutch model PSC-70 from specification chart 2.67 x Inertia (lb-in2 ) x = 2.67 x 18 x 800 (10000 ) PM (10000 ) x F cycle min 2 x 300 = 92 watts Select clutch model PSC-120 from specification chart Magnetic Particle Clutches & Brakes 141 Magnetic Particle Clutches & Brakes Torque = Tension (lbs) x Full Roll Diameter (in) 2 = 2 x 8 = 8 lb-in 2 12 x Velocity (fpm) Core RPM = π x Core Diameter = 12 x 200 = 382 RPM πx2 12 x Velocity (fpm) Full Roll RPM = π x Full Roll Diameter (in) = 12 x 200 = 95 RPM πx8 Cycling 2 Torque (lb-in) = Inertia (lb-in ) x RPM 3690 x time(s) = 144 x 1000 = 10 lb-in 3690 x 4