62 



Indiana University Studies 



The most common type of engine in quarry service is the 

 simple Atlas engine. These engines are usually of the older 

 types and are in most cases in poor condition. Most of the mills 

 are equipped with Corliss valve engines, among which the Atlas 

 and Hamilton-Corliss are the most common. There are a few 

 automatic engines in use in the district, and in every case save 

 one they were reported to be giving entire satisfaction. The 

 automatic engines are best adapted to mill work, where they 

 can be used direct connected to the generator, for the generation 

 of electricity. There will be a tendency to increase the number 

 of automatic engines as the amount of electrical equipment in- 

 creases, for the}^ are proving far more satisfactory in this work 

 than the slower engines. The direct-connected generator gives 

 better satisfaction than the belt-driven types. The automatic 

 engine is best fitted to handle the sort of load that is necessary in 

 mill work. Where most of the machinery is handled from a line 

 shaft, the slower Corliss engines seem to be better adapted and are 

 doing the work in a satisfactory manner wherever they are in- 

 stalled. 



The steam lines are protected by covering in only a few cases, 

 and in many plants are so long as to cause a serious loss of power 

 on account of radiation between boiler and engine. The main 

 work of the quarry engine is derrick handling, and as a rule this 

 work is very hard on an engine. In many cases these engines 

 are only protected by a roof and in a few cases they are entirely 

 exposed to the weather. There appears to be a marked tendency 

 among the quarry men to replace the steam engine used on 

 derrick work by motors and thus concentrate the power in one 

 large engine. This is a wise move, inasmuch as the cost of driv- 

 ing several small units is far greater than the cost of generating 

 all the power in a single unit. 



Wherever there is complaint against driving machinery from 

 a line shaft, the loss of power can nearly always be traced directly 

 to the shafting, where the cause of loss is usually found to be in 

 improper alignment of the shafting or worn bearings. The 

 power losses due to poor shafting and belting often represent a 

 large percentage of the power generated by the engine, and in 

 every such case the tendency is to lay the blame on the engine, 

 without having first made the proper tests to determine the real 

 cause of the losses. 



The electrical equipment of the mills is almost entirely West- 

 inghouse or General Electric Company machinery. Wherever 



