94 



MOTIVE POWER IN MANUFACTORIES 



rents over large areas is necessary, three- 

 phase current (2,300 volt, 60 -cycle trans- 

 mission, transformers for supplying 220 

 or 440 volts) is advised. 



It is much better, usually, to buy 

 the current from a central power station 

 than to produce it from mill refuse 

 through the medium of steam. 



III. In ascertaining the power requir- 

 ed for a plant, there must be considered : — 



(a) The continuously operated 

 machines (notably the blowers; 

 the "fanload" amounts to from 

 25 to 40 per cent of total power 

 where a central blower system Three -roi 

 is used). 



(b) The intermittently operated machines. 



The electric current is inferior to steam power in one important point: -In the steam engine, the 

 boiler acts as a storage of reserve power, so that for short periods of time a machine can be supplied 

 with a power surplus. In other words, steam power is pliable; electric power (alternating) is stiff. 



If the motor meets a resistance which it cannot overcome, something must break. Steam in such 

 a case would act as a buffer. 



In installing motors, be sure to instal motors of sufficient power surplus. 



Power requirements are, appro.\imately:- 



sander, electrically driven, Westinghouse Electric Co., 

 East Pittsburgh, Penns. 



42-inch band ripsaw 



30-inch planer 



24-inch planer 



60-inch veneer knife 

 Double cut-off saw 



10 horse-power 



15 horse-power 



10 horse-power 



3 horse-power 



5 horse-power 



Pony surfacer, electrically driven. 

 Westinghouse Electric Co., East Pittsburgh, Penns. 



Seven-inch molder driven by Westinghouse motor. 

 Westinghouse Electric Co., East Pittsburgh, Penns. 



