CHAPTER VI
STEAM ENGINE TESTING
The principal information sought in the usual test of a steam engine is:
1. The indicated horsepower developed under certain standard conditions.
2. The friction of the engine, from which is determined the mechanical efficiency.
3. The steam consumption per indicated horsepower.
4. The general action of the valves.
5. The pressure conditions in the cylinder at different periods of the stroke.
The ultimate object of an efficiency test is to determine the foot-pounds of work delivered by the engine per pound of coal burned in the boiler furnaces. The general method of finding the pounds of dry steam evaporated per pound of coal has been treated in Machinery’s Reference Series No. 67, “Boilers,” under the head of “Boiler Testing.” In the present case it is, therefore, only necessary to carry the process a step further and determine the foot-pounds of work developed per pound of steam.