A four-pole separately excited wave-wound DC machine with negligible armature resistance is rated 230 V,5 kW at 1200 rpm. The same coils are reconnected in lap winding at the same speed and field. Its voltage and power ratings are
A simplex wave winding has two parallel paths, whereas a four-pole simplex lap winding has four. Generated voltage is inversely proportional to path count, so it halves from 230 to 115 V.
The same coil-current limit allows twice the terminal armature current with twice as many paths. Voltage halves and current doubles, preserving the 5 kW power rating. Hence **115 V and 5 kW, B**.
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