An inverted V curve of synchronous motor shows variation of
A. power factor and DC excitation at constant load.
B. supply voltage and field current at constant excitation.
C. power factor and supply voltage during hunting.
D. supply voltage and excitation current at constant load.
Answer: A
Share your understanding of this question with the correct explanation.
An inverted V curve of a synchronous motor shows the variation of power factor and DC excitation at a constant load.
The inverted V curve is a graphical representation of the power factor versus the field excitation current of a synchronous motor. It shows how the power factor of the motor changes with variations in the DC excitation current while the motor is operating at a constant load.
At low levels of excitation current, the power factor is lagging, indicating a less efficient operation. As the excitation current is increased, the power factor improves and eventually reaches unity (1.0) or becomes leading. This is the peak of the inverted V curve. Further increasing the excitation current beyond this point causes the power factor to deteriorate and become lagging again.
The inverted V curve provides valuable information about the operating characteristics of a synchronous motor and helps in determining the optimum excitation level for achieving a desired power factor.
Therefore, option A, “power factor and DC excitation at constant load,” is the correct answer.