1. A 480 V, 20 kW shunt motor took 2.5 A, when running light. Taking the arma ture resistance to be 0.6 Ω, field resistance to be 800 W and brush drop 2 V, find the full-load efficiency.
2. The open-circuit characteristic for a dc generator at 1200 rpm is:
Estimate the critical field resistance at this speed. Keeping the field resistance fixed at this speed, the generator is run at 1600 rpm. What would be the no-load voltage?
The generator is now loaded to an armature current of 500 A. Estimate the terminal voltage and line current (at 1600 rpm). Neglect armature reaction effects.
