please answer with steps A shunt connected 750 kW 250 V dc

please answer with steps

A shunt connected 75.0 |kW|. 250. | V| dc motor has an armature resistance of 45.0 |m Ohm | and a field resistance of 185 | Ohm |. With nothing connected to tire motor shaft. 250. |V| Is applied to the motor terminals, the speed is 1850 |RPM| and armature current Ia = 3.00 [A] Calculate no-load copper losses - 5 points Calculate total no load copper (I^2R} losses. Calculate friction/windage losses Calculate the total friction and windage losses. Calculate load copper losses - 5 points The applied terminal voltage remains 250. |V|. hut load conditions have changed, and the motor terminal current I_t (which is not the armature current} is 290 |A|. Calculate total copper (I^2R; losses. Calculate Ea - 5 points Calculate the armature back emf En for the conditions described in Section 1.4.

Solution

1.1) under no-load condition load draws 10 % of the rated current, so armature current= 0.3 amps

no-load copper losses=(ia)^2*Ra=(0.3)^2*45*10^-3=4.05*10^-3 watts.

1.3) motor terminal current=290 amps

terminal current=armature current+field current.

field current=(250/185)= 1.351 amps

armature current=290-1.351=288.649amps

armature copper losses= 45*10^-3*(288.649)^2= 3.749 kw.