Question

When a rated load with 0.8 lagging power factor is supplied, the terminal voltage of a single phase alternator with a certain interference is 200 V. With the same interference, the voltage developed in the open circuit is 230 V. What will be the voltage regulation of the alternator?
1. 25%
2. 13%
3. 15%
4. 10%

Answer 1

Correct Answer - Option 3 : 15%

Concept:

The voltage regulation of an alternator is defined as the ratio of the rise in voltage when full-load is removed (field excitation and speed remaining the same) to the rated terminal voltage.

% voltage regulation \( = \frac{{{E_0} - V}}{V} \times 100\)

Where E0 is the no-load voltage

And V is the rated voltage

Calculation:

Given: no-load induced emf (E0) = 230 V

Rated terminal voltage (V) = 200 V

Voltage regulation \( = \frac{{230 - 200}}{{200}} \times 100 = 15\% \)