. Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry . lifting cables is due to the force re-quired to accelerate, hoist the unbalanced load, overcome^friction in the guides of both car and counterweight, andthe air friction of the car and other moving parts of thesystem. The pull on the cables due to the acceleration is theproduct of the mass and the acceleration of the car. Theadditional pull due to the load is dependent upon the un-balanced weight and is readily obtainable. Th
. Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry . lifting cables is due to the force re-quired to accelerate, hoist the unbalanced load, overcome^friction in the guides of both car and counterweight, andthe air friction of the car and other moving parts of thesystem. The pull on the cables due to the acceleration is theproduct of the mass and the acceleration of the car. Theadditional pull due to the load is dependent upon the un-balanced weight and is readily obtainable. The variousfriction losses must be estimated from tests on previousinstallations of a similar character. It is fortunate in thisconnection that windage losses are least at starting andbecome a maximum at full speed where the accelerationbecomes zero. Having these three the total pull on theropes is equal to their sum. This pull when multiplied bythe radius of the driving sheave gives the torque which mustbe applied to the sheave shaft in order to exert this pullon the cables. If this torque is divided by the efficiency of ?0 25 30 40 SO 60 70 150 200 300 400 500 600. *Passenger Elevators, Transaction of the American Society ofCivil Engineers, Vol. LIV., Fart B, 1905, ZO 15 30 40 SO 60 80 100 ISO MO JOO 400 500 WO Speed of Car in Feef Per Minufe. Chart for Determining Horsepower of a Motor the gear it will give the torque which must be providedby the motor. The required electrical input to the motor is obtainedby dividing the torque at the shaft by the motor efficiencyat the given load and speed. It must be noted that all the foregoing quantities varywith the speed and the complete analysis involves consider-able computation. The problem is made still more com-plicated by the inherent characteristics of the elevatorcontrol. The total power input to the motor must be thatused in the motor and that lost in the starting resistancesand other control apparatus. ELECTRIC ELEVATORS 47; F
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Keywords: ., bo, bookcentury1900, bookdecade1920, booksubjecthoistingmachinery
