Parallel Operation of Alternators

When two or more alternators are connected in parallel, the following conditions must be met:

- Same frequency and phase sequence
- Same voltage magnitude
- Same phase angle

Effect of Changes in Driving Force

The driving force of an alternator is the mechanical power input required to rotate the rotor and generate electrical power. This is usually provided by a prime mover such as an engine or turbine.

If the driving force of both alternators is changed simultaneously, this will result in a change in the frequency of the output voltage. This is because the frequency of the generated voltage is directly proportional to the speed of rotation of the rotor, which is in turn proportional to the driving force.

Therefore, if the driving force is increased, the speed of rotation and frequency of the output voltage will also increase. Similarly, if the driving force is decreased, the speed of rotation and frequency of the output voltage will also decrease.

Effect on Back EMF and Generated Voltage

However, the change in driving force will not have a direct effect on the back EMF or generated voltage of the alternators. This is because these parameters are determined by the design of the alternator and the magnitude of the magnetic field.

Therefore, if the driving force is increased, the back EMF and generated voltage will remain the same. Similarly, if the driving force is decreased, the back EMF and generated voltage will also remain the same.

Conclusion

In summary, when two alternators are running in parallel, any changes in the driving force will result in a change in the frequency of the output voltage. However, the back EMF and generated voltage will remain the same.