The ‘synchronous-impedance method’ of finding the voltage ...
As unsaturated value of Zs is more than the saturated value, voltage regulation computed by emf method is much higher than the actual value. It is because of this reason that the emf method is called a pessimistic method.
View all questions of this test
The ‘synchronous-impedance method’ of finding the voltage ...
Synchronous-impedance method is a commonly used method to find the voltage regulation of a cylindrical rotor alternator. It is based on the assumption that the rotor of the alternator has a uniform distribution of magnetic poles and that the rotor and stator are aligned perfectly. The method involves finding the synchronous impedance, which is the ratio of the open-circuit voltage to the short-circuit current at synchronous speed.
Pessimistic Method
The synchronous-impedance method is considered a pessimistic method because it does not consider the saturation of the rotor iron. Saturation occurs when the magnetic flux density in the rotor iron reaches its maximum value, which causes a reduction in the inductance of the rotor. This reduction in inductance results in an increase in the rotor current and a decrease in the output voltage, which is not taken into account in the synchronous-impedance method.
Optimistic Method
The synchronous-impedance method is not considered an optimistic method because it does not consider the effects of saturation, which can cause the voltage regulation to be higher than predicted. An optimistic method would assume that the alternator operates at its ideal conditions, which is not the case in practice.
Accuracy of Method
The synchronous-impedance method can be a fairly accurate method of finding the voltage regulation of a cylindrical rotor alternator, especially when the power factor is taken into account while determining the synchronous impedance. However, the method does not take into account the effects of saturation, which can result in a higher voltage regulation than predicted.
Conclusion
In conclusion, the synchronous-impedance method is a commonly used method to find the voltage regulation of a cylindrical rotor alternator. However, it is considered a pessimistic method because it does not consider the effects of saturation, which can result in a higher voltage regulation than predicted.
To make sure you are not studying endlessly, EduRev has designed Electrical Engineering (EE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Electrical Engineering (EE).