I have completed a DC generator chapter from my course book. Below mentioned questions have been asked in previous examinations, but my course book doesn't help in solving these. Please help me with the reference books which will be helpful in solving these type of questions. I am pursuing Aeronautical Engineering through correspondence, hence I lack guidance. It's like self study. 1. Find the ampere-turns per pole of field excitation required for the single gap of a 2-pole DC generator with the following particulars : 200 V on no load at 2000 rpm, armature length 32 cm, effective gap length 0.8 cm, pole arc 30 cm and 200 armature conductor. 2. A 10 kW, 1440 rpm desperately excited generator has resistance loss of 400 W in the field winding under normal operating conditions. The time constant of the field winding is 0.2 secs. Calculated the energy stored in the magnetic field produced by the field winding. 3. Find the number of poles for a 1200 kW separately excited DC generator if the average voltage between commutator segments is 15 V and the armature ampere turns per pole on full load is 10000. The generator has single turn coil and is lap connected. Ignore all losses.