In what way does the ampere turn method differ from synchronous impedance method?

29. In what way does the ampere-turn method differ from synchronous impedance method? The ampere-turn /MMF method is the converse of the EMF method in the sense that instead of having the phasor addition of various voltage drops/EMFs, here the phasor addition of MMF required for the voltage drops are carried out.

Why EMF method gives the higher value of voltage regulation?

The voltage regulation of alternator by EMF method involves the EMF quantities of all the armature parameters (armature resistance, Armature leakage reactance, armature reaction). This method is also called pessimistic method, because the voltage regulation obtained by this method is more than the actual value.

Which method gives large value of synchronous reactance?

synchronous impedance method
The synchronous impedance method or the EMF method is based on the concept of replacing the effect of armature reaction by an imaginary reactance. This method gives result which is higher than the original value.

Why is the synchronous impedance method of estimating voltage regulation is considered as pessimistic method?

Synchronous impedance method gives result which is higher than the original value. That’s why it’s called the ‘pessimistic method’. Armature turn or mmf method gives value which is lower than the original value. It is based on the separation of armature leakage reactance drop and the armature reaction effects.

What are the advantages and disadvantages of synchronous impedance method?

Advantage: synchronous impedance Zs for any load condition can be calculated. Hence regulation of the alternator at any load condition and load power factor can be determined. Limitation: This method gives large values of synchronous reactance. This leads to high values of \% regulation than the actual.

Why synchronous impedance method is called EMF method?

The synchronous impedance method or EMF method is used to determine the voltage regulation of the larger alternators. The synchronous impedance method is based on the concept of replacing the effect of armature reaction by an imaginary reactance.

Why EMF method is called synchronous impedance method?

Which of the following method gives more accurate voltage regulation?

Which of the following voltage regulation method is accurate? In Potier Triangle or ZPF method, voltage quantities are calculated on emf basis and mmf quantities are calculated on mmf basis. Therefore, ZPF method is most accurate among all these four methods.

Why MMF method is known as optimistic method?

The field mmf (If1) required to induce the rated terminal voltage is obtained by conducting open circuit test. This method is also called an optimistic method because the voltage regulation obtained by this method is less than the actual value.

Why is EMF method of voltage regulation called pessimistic method?

The synchronous impedance method or the EMF method is based on the concept of replacing the effect of armature reaction with an imaginary reactance. This method is not accurate as it gives a result that is higher than the original value. That’s why it is called the pessimistic method.

Which method gives most accurate result for voltage regulation of an alternator?

Z.P.F method gives most accurate result for finding voltage regulation of an alternator.