MOTIVE POWER IN MANUFACTORIES 



93 



These figures hold good for 

 single cylinder engines and are lower 

 than the usal catalogue figures. A new 

 engine develops more power than an 

 old one. 



4. The flywheel should weigh 600 pounds 

 for every inch of cylinder diameter. 



5. Engines cannot get along any better, 

 without care, than horses. Repair and 

 watch the smallest defects ! Have the 

 firmest possible foundations! 



6. Sawmill engines are put to the se- 

 verest possible tests owing to frequent 

 and rapid change of strain. 



(E) ELECTRICITY. 



I. The electric drive in woodworking 

 plants has come to the front rapidly in 

 recent years, owing to the following ad- 

 vantages : — 



(a) Most effective arrangement of ma- 

 chines. The motors can be placed ver- 

 tically or horizontally, at any distance 

 from the power source, and at any 

 distance one from the other. Fre- 

 quently, nevertheless, several like ma- 

 chines are driven in groups from one 

 motor; 



(b) Easy connection of driving power to 

 load; 



(c) Ease of extension of plant in any 

 direction ; 



(d) Minimizing of losses in transmission. 

 There are less belts and less shafts. 

 The main shafts are idle during 35 

 to 90 per cent of their running time; 



(e) Ease of determining power cost for 

 each machine; 



(f) Less congestion on floor of plant; 



(g) Minimum fire risks and insurance 

 charges; 



(h) Reduced oil bills. 



Load factor is the ratio of actual 

 average load to total connected load. It 

 varies in woodworking plants between 

 3 and 50 per cent. 



II. The current supplied is either 

 alternating (usually) or direct (e. g., in 

 case of adjustable speed tools like wood 

 lathes). If the distribution of heavy cur- 



Trimmers, electrically driven. Westiiighouse Electric Co., 

 East Pittsburgh, Perms. 



Band resaw, electrically driven. Westinghonse Electric Ct 

 East Pittsburgh, Penns. 



Thirty- inch double surfacer, electrically driven. Westinghouse Electric Co., 

 East Pittsburgh, Penns. 



