238 



THE WORLD'S ADVANCE 



the small pulley exchanged places with 

 a larger one having a flange to serve as 

 a balancing flywheel. After an initial 

 charging of the field by connecting it to 

 the ignition battery of the engine, this 

 little piece of junk started generating 

 without the slightest difficulty and for 

 all the writer knows it is still working, 

 although at this writing the machine has 

 been out of his possession for a matter 

 of five years. On a slight overload the 

 fields would run warm, and in order to 

 cool them a crude fan was attached to 

 the pulley inside the rim. This com- 

 pletely obviated the difficulty, and after 

 its adoption the generator would deliver 

 for half an hour at a time more than 

 twice the current it was intended to sup- 

 ply, without developing serious heat. 



The remarks in the last paragraph are 

 given solely with the idea of offering a 

 suggestion to the handy man who feels 

 that he is courageous enough to attempt 

 the rewinding of an old machine. The 

 principal point to look out for in the 

 buying of such a machine is the form of 

 lubrication and the size of the shaft and 

 bearings. The conventional wick oiler so 

 frequently found in small motors is quite 

 satisfactory if the proper lubricant is 

 used and assuming, of course, that the 

 wick is held against the shaft by means 

 of a spring of the correct strength. The 

 ideal oiler is the ring type, and if the 

 machine is so equipped the worker need 

 not look much further beyond ascertain- 

 ing whether or not the bearings are fairly 

 snug and the shaft in good condition. 

 A machine equipped with ordinary oil- 

 cups or oil holes in the bearings is nine 

 times out of ten a poor buy except for 

 purely experimental work. So much for 

 the dynamo. 



If the worker is fortunate enough to 

 have a small stream on or near his place, 

 three-quarters of his problem is solved. 

 The amount of water power needed to 

 turn a loo-watt generator is so small 

 that the crudest type of waterwheel will 

 answer in most cases. This question of 

 water power is brought up at the present 

 point before the selection of a gasoline 

 engine is suggested, and water power in 

 the case of the summer cottage is, in 

 more ways than one, ideal. 



If the water power is found to be un- 

 available, however, the worker had best 

 resort to the gasoline engine. In this 

 event the plant would be housed beneath 

 the seat on the porch. The engine need 

 not be larger than a half or even a quar- 

 ter horsepower if the rating is honestly 

 given. Air cooling is satisfactory if the 

 machine is properly designed and 

 equipped with a cooling fan, but a water- 

 cooled machine is to be recommended if 

 available. There is little choice between 

 two and four-cycle machines, but in 

 either case the engine should be gov- 

 erned closely. A new engine is advised 

 unless a second-hand machine can be ob- 

 tained from a responsible dealer who will 

 guarantee the condition of its valves, 

 bearings, cylinder and piston. In the in- 

 ternal combustion engine these parts are 

 subjected to strains that weaken the out- 

 put of power without materially affecting 

 the running qualities of the engine when 

 the load is off. 



Assuming that the dynamo and engine 

 have been obtained, the worker may pro- 

 ceed to assemble them, preferably on two 

 substantial struts of wood, the dynamo 

 being so mounted that it may be slid for- 

 ward or backward to tighten or loosen 

 the belt. The skids may rest on thick 

 pads of rubber or felt fastened to the 

 porch floor, or, better still, four upright 

 posts may be set in the ground beneath 

 the porch, passing up through its floor 

 without touching, to afford a substantial 

 foundation for the little plant, which is 

 thus independent of the cottage, although 

 housed by it. The vibration is likely to 

 be annoying unless some provision is 

 made in this manner to absorb it. 



The belt from engine to generator 

 should be long and pliable ; a tight, short 

 belt has no place here. The gasoline 

 should preferably be kept in an under- 

 ground tank a short distance from the 

 cottage and fed under slight air pressure 

 through copper tubing to the engine. The 

 voltage of the dynamo should be made 

 variable through the insertion of a small 

 rheostat in the field circuit. The leads 

 from the dynamo are secured to the 

 right-hand poles of the switchboard 

 shown in the preceding installment of 

 this series. 



