Ques. Why is the reciprocating engine being largely replaced by the steam turbine, especially for large units?
Ans. Because of its higher rotative speed, and absence of a multiplicity of bearings which in the case of a high speed, reciprocating engine must be maintained in close adjustment for the proper operation of the engine.
The higher speed of rotation results in a more compact unit, desirable for driving high frequency alternators.
Ques. Is the steam turbine more economical than a high duty reciprocating engine?
Ans. No.
Location of Central Stations.—As a rule, central stations should be so located that the average loss of voltage in overcoming the resistance of the lines is a minimum, and this point is located at the center of gravity of the system. In [fig. 2,706] is shown a graphical method of locating this important spot.
Fig. 2,706.—Diagram illustrating graphical method of determining the center of gravity of a system in locating the central station.
Suppose a rough canvass of prospective consumers in a district to be supplied with electric light or power shows the principal loads to be located at A, B, C, D, E, etc., and for simplicity assume that these loads will be approximately equal, so that each may be denoted by 1 for example: