Question
Download Solution PDFA DC generator efficiency is maximum when:
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFEfficiency is defined as the ratio of output power to the input power.
Generator efficiency is given by the equation
The efficiency of a DC generator is maximum when those losses proportional to the square of the load current.
Variable losses are equal to the constant losses of the DC generator i.e. armature circuit loss is equal to the sum of no-load rotational loss and field circuit loss.
Variable loss - Constant loss = 0
Mechanical losses = friction loss of bearings + friction loss at a commutator + windage loss.
Core losses = hysteresis loss + eddy current loss
Stray loss = mechanical loss + core loss
Constant losses = Shunt field copper losses + stray loss
Constant losses are almost fixed and do not vary with the load current
Current at maximum efficiency
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