What is phasor diagram of alternator?
The phasor diagram of an alternator supplying a load of lagging power factor is shown in Figure-3. Here, the power factor is ? lagging. To draw this phasor diagram, the terminal voltage V is taken as reference phasor and its direction is along OA where, OA = V.
How do you plot a phasor diagram?
By drawing out the two phasors to scale onto graph paper, their phasor sum V1 + V2 can be easily found by measuring the length of the diagonal line, known as the “resultant r-vector”, from the zero point to the intersection of the construction lines 0-A.
What is the power factor of alternator?
Power factor is actually determined by the nature of load connected to the alternator. Normally, the power factor is around 0.8 lagging. Ideally, power factor should be equal to unity (purely resistive load) which results in maximum efficiency and maximum capacity utilization.
What is excited generator?
motor is over excited: Leading PF. If a generator is under excited: lagging PF. If a Sync. motor is under excited: lagging PF.
What is difference between phasor diagram and vector diagram?
A phasor is a rotating vector. Whereas a vector represents quantity and direction, a phasor represents quantity and displacement measured in a counterclockwise direction. Phasors are used in electrical engineering to represent certain AC quantities -e.g. the relationship between current and voltage.
What is 0.8 power factor?
0.8 power factor is a measure of the delay or lead of current flow as compared to the application of the driving voltage. As A generator’s magnetic field is rotated around inside the stator the voltage it generates, when applied to a load, will force a current flow.
What is the EMF equation of 3 phase alternator?
= RMS value = Form Factor x Average Value, VAV = 1.11 x 4fΦT = 4.44fΦT Volts.
What is a three-phase alternator?
The three-phase alternator, as the name implies, has three single-phase windings spaced such that the voltage induced in any one phase is displaced by 120º from the other two.
What is the relationship between voltage and current phasor?
The current phasor lags the voltage phasor by the angle, Φ, as the two phasors rotate in an anticlockwise direction as stated earlier, therefore the angle, Φ is also measured in the same anticlockwise direction. If however, the waveforms are frozen at time, t = 30o, the corresponding phasor diagram would look like the one shown on the right.
How are voltage waveforms generated across each phase of an alternator?
The voltage waveforms generated across each phase are drawn on a graph, phase-displaced 120º from each other. The three-phase alternator as shown in this schematic is made up of three single-phase alternators whose generated voltages are out of phase by 120º.
What is the phase relationship between armature and current in alternator?
The phase relationship between armature induced emf E due to field flux φf and the current flowing through the armature I a depends upon the power factor of the load. When the alternator is driving a unity power factor load ( resistive ) i.e., cos φ = 1. The armature current I a will be in phase with V ph as shown below.