Bucket Elevator Selection Method: The torque capacity of the selected Cam Clutch must be greater than the calculated torque (T), must accept the required shaft speed, and be suitable for the bore and installation method required.
Cam Clutch
Chain and sprocket
Torque arm
Bucket
Metric formula: T(Nm) =
Motor speed reducer
9.8 x (L + D) x Q x 1000
x Service Factor
120 x V
L = Total lift in meters D = Pitch diameter of head sprocket in meters Q = Maximum possible load in tons per hours (1 ton = 1000 kg)
V = Velocity of conveyor in meter/minute SF = Service Factor from Table on page 16
Belt Conveyor Selection Method: Using these calculations, a slightly smaller Cam Clutch might be suggested because friction factors inherent in the belt conveyor are taken into consideration. Any calculations from this formula should be compared with the Motor Stall Torque Selection Method. We strongly suggest that any Cam Clutch selection be based on the larger value and choose the Cam Clutch that provides a greater safety factor. Please contact Tsubaki with any questions.
Selection Procedure: (1) Calculate the power to move an empty belt and idlers: (P1)
BS Cam Clutch
Belt conveyor
ℓ + ℓ 0
P 1 = 0.06 x f x W x V x
(kW)
Torque arm
367
(2) Calculate the power to move a loaded belt horizontally: (P2)
Motor
Speed reducer
ℓ + ℓ 0
P 2 = f x Qt x
(kW)
367
Note: f = Friction coefficient of rollers (0.03 normally used) h = Total lift (m) ℓ = Horizontal distance between head pulley and tail pulley (m) ℓ 0 = Modification coefficient for ℓ (49 m normally used ) N = Shaft speed on which the clutch is mounted – r/min Q = Max. possible load in tons per hour (metric ton/hr.) SF= Service factor V = Velocity of conveyor (m/min) W = Weight of moving parts of the conveyor in the unloaded condition (kg/m) 400 450 500 600 750 900 Estimated Weight: W 22.4 28 30 35.5 53 63 Width of Belt (mm) 1050 1200 1400 1600 1800 2000 Estimated Weight: W 80 90 112 125 150 160 (W) Estimates for non-loaded belt weight (kg/m) Width of Belt (mm)
(3) Calculate the power to move the load vertically: (P3)
h x Qt
P 3 =
(kW)
367
(4) Calculate the backstop power: (Pr)
Pr = P 3 - 0.7(P 1 + P 2 ) (kW)
(5) Calculate the backstop torque: (T)
9550 x Pr
T =
x SF (N m)
N
(6) Select the proper clutch which satisfies the calculated backstop torque (T)
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