What are the advantages of MMF 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.

Which is the optimistic method of finding voltage regulation?

Armature turn method: It is also known as MMF method. It gives a value which is lower than the original value. That’s why it is called an optimistic method.

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

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

Which method is the most efficient method of predetermination of alternators?

For Alternators of such power and voltage ratings conducting load test is not possible. Hence other indirect methods of testing are used and the performance like voltage regulation then can be predetermined at any desired load currents and power factors.

What are the test data required for predetermining the voltage regulation of an alternator by MMF method?

Data required for MMF method are : • Effective resistance per phase of the 3-phase winding R • Open circuit characteristic (OCC) at rated speed/frequency • Short circuit characteristic (SCC) at rated speed/frequency 31. The phase sequence of the incoming Alternator voltage must be similar to the bus-bar voltage.

What is the difference between EMF and MMF?

EMF is the force that is responsible for driving the electrons in an electric circuit. Magnetomotive force is abbreviated as MMF. MMF is the driving force required to drive the magnetic flux through the circuit.

Which is the direct method for calculating voltage regulation of alternator?

Direct method of determining the voltage regulation is employed for smaller machines. In this direct method, a three phase load is connected to star connected alternator with the help of Triple Pole Single Throw switch. The field winding of alternator is excited using an external DC supply.

Why it is necessary to determine the voltage regulation of an alternator?

A knowledge of voltage regulation at different power factors are usually essential because it shows how closely a machine will maintain its voltage under the various conditions of load. This knowledge is also important from the point of voltage control, parallel operation and protection of the alternators.

What is mmf method of voltage regulation?

MMF Method is also known as Ampere Turn Method. The MMF method replaces the effect of armature leakage reactance with an equivalent additional armature reaction MMF so that this MMF may be combined with the armature reaction MMF. …

What is EMF and mmf method?