The following data apply to a 100-kW, 250-V, six-pole, 1000-r/min long-shunt compound generator: no-load rotational losses 4000 W, armature resistance at 75°C = 0.015 , series-field resistance at 75°C = 0.005 , interpole field resistance at 75°C = 0.005 , and shunt-field current 2.5 A. Assuming a stray-load loss of 1% of the output and a brush-contact resistance drop of 2 V, compute the rated-load efficiency.