Hines Exam Aug-Oct 2020: Electrical Engineering - Shunt Generators

Vocabulary and concepts derived from a specific electrical engineering exam question regarding shunt generator calculations and properties.

Prime mover input (Question 13)

The mechanical power supplied to the shunt generator, which in this scenario is $60\,hp$.

Generator Load Current ($I_L$)

The current delivered to the load from the generator terminal, specified as $150\,A$ in Question 13.

Terminal Voltage ($V$)

The voltage measured at the generator load terminals, which is $240\,V$ in the provided problem.

Generated Voltage ($E_g$)

The internal voltage produced by the generator; in a shunt generator, it is greater than the terminal voltage due to the internal voltage drop ($E_g = V + I_a R_a$).

Rotational losses

Power losses caused by friction and windage in the machine; they are distinct from copper ($I^2 R$) losses.

Horsepower ($hp$) to Watt ($W$) conversion

The standard unit conversion where $1\,hp = 746\,W$, making the input power for the 60-hp mover approximately $44,760\,W$.

Output Power ($P_{out}$)

The product of the terminal voltage and the load current ($P_{out} = V \times I$); for this problem, $240\,V \times 150\,A = 36,000\,W$ or $36\,kW$.

Generator Efficiency ($\eta$)

The ratio of output power to input power ($\eta = \frac{P_{out}}{P_{in}}$). For the generator in Question 13, efficiency is approximately $80.4\%$.

Shunt field connection

A configuration where the field winding is connected in parallel with the armature and the load.