$250$ Volt Ra$+$Rs $=0,08$ ohm DC series connected motor, under some load which requires constant power, armature current is $50$ amp. Magnetization characteristic $($MC$)$ of the machine is given by following equation $$at constant speed of n$=1200$ rpm ea$($If$)=1,6$ x If volt$.($shaft speed means mechanical speed$)$Example of MC: when the If is $100$ amp, Ea is $160$ Volt at $1200$ rpm$.$ What will be the terminal voltage for the mechanical speed of $2830$ rpm$?$ Hint First you need to find the speed and power when the armature current is $50$ A$.$