Electrical Engineering ⇒ Topic : Efficiency curve

Efficiency curve. The efficiency of a machine is different at different values of power output. As the output increases, the efficiency increases till it reaches a maximum value. As the output is further increased, the efficiency starts decreasing. A graph of efficiency vs. output is called efficiency curve. At typical efficiency curve is shown in Fig. (a). The machines are so designed as to give maximum efficiency at or near the rated output of the machine. Since the generators operate at a constant terminal voltage V,the efficiency curve of a generator can be drawn between efficiency and load current I.

                                         Fig.(a) Efficiency curve.