Final answer:
This question relates to the analysis of a synchronous motor connected to a DC generator driven by a turbine, focusing on the back emf, mechanical power output, power dissipation in resistances, and total power output of the system.
Step-by-step explanation:
A 3-phase, 4-pole, 6MVA, 13.8kV, 60Hz synchronous machine operated as an AC motor with a rotor DC resistance (Rr) of 1.5Ω is connected to a DC generator with an armature resistance (Ra) of 0.4Ω. This generator is powered by a turbine and produces a DC output voltage (Vpc) of 480V at a generator speed of 1000RPM. The synchronous motor carries a load with a power (Psyn) of 1.98MW and a power factor (PF) of 0.95 lagging.
To analyze this system's operation, various calculations may be involved, which can include determining the back electromotive force (emf), the mechanical power output, power dissipation in the resistances, and total power output of the system. The back emf is particularly important in motors and generators, influencing their efficiency and performance.
The back emf acts against the driving emf and is proportional to the motor's angular velocity. During operation when electrical power is converted to mechanical power, you have to consider not only the power drawn from the source but also the losses in the system, which include the power dissipated in the resistance of the coils.