A 25 Kw series generator has an efficiency of 85%
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A 25 Kw series generator has an efficiency of 85% when operating at rated load. If the stray-power loss is 20% of the full-load loss, calculate the efficiency of the generator when it is delivering a load of 15Kw, assuming that the stray-power loss is substantially constant and the other losses vary as the square of the load.