What is the nature of armature reaction of alternator with the power factor is zero power factor leading?
Zero power factor lagging: The armature reaction is entirely De-magnetising in nature. The net flux reduces the load to reduce the terminal voltage. Voltage regulation is positive.
What is zero factor leading the effect of armature reaction in an alternator on the main flux is?
Detailed Solution
| Power factor | Alternator |
|---|---|
| Unity power factor (UPF) | Purely cross magnetization |
| Zero power factor (ZPF) lagging | Purely demagnetization |
| Zero power factor (ZPF) leading | Purely magnetization |
| 0.9 lagging | Partly demagnetizing and partly cross magnetization |
What is armature reaction in generator?
3.10 Armature reaction in d.c. generators. Armature reaction is the effect on the main field flux of that flux set up by the currents in the armature winding. 3.7 shows the two main poles of a d.c. generator and the distribution of the magnetic flux which crosses the airgap and enters the armature.
When the power factor of an alternator is unity then armature flux will be?
22. In an alternator, when the load power factor is unity. Answer: (b) the armature flux will be cross-magnetizing.
What is the armature reaction in an alternator?
Armature reaction is defined as the effect of armature flux on the main flux produced by the field poles. When the load is applied to the alternator, current starts flowing through the armature conductors. Since the current is alternating in nature, it induces a flux in the conductor, called as armature flux.
What is armature in alternator?
In electrical engineering, the armature is the winding (or set of windings) of an electric machine which carries alternating current.
What is armature reaction in alternator?
What is armature reaction effect in alternator?
This reverse effect is referred as armature reaction in alternator or synchronous generator. In other words, the effect of armature (stator) flux on the flux produced by the rotor field poles is called armature reaction.
What is armature reaction of alternator?
How do you reduce the armature reaction in an alternator?
1) The armature reaction causes the distortion in main field flux. This can be reduced if the reluctance of the path of the cross-magnetizing field is increased. The armature teeth and air gap at pole tips offer reluctance to armature flux. Thus by increasing length of air gap, the armature reaction effect is reduced.
What are the main effects of armature reaction?
Armature reaction has two undesirable effects: First, it distorts the main field. Secondly, it reduces the main field flux or both. When the main field is distorted, then there will be a cross magnetizing effect.
What is the effect of power factor on armature reaction?
When an alternator supplies a load at unity power factor, the effect of armature reaction is partly cross magnetizing and partly distorting. The effect of armature reaction is demagnetizing, when an alternator supplies a load at lagging power factor.
What is the effect of armature reaction on an alternator?
The effect of armature reaction is demagnetizing, when an alternator supplies a load at lagging power factor. When an alternator supplies a load at leading power factor, the effect of armature reaction is magnetizing.
When an alternator supplies a load at leading power factor?
When an alternator supplies a load at leading power factor, the effect of armature reaction is magnetizing. When an alternator supplies a load at intermediate power factor, the effect of armature reaction is partly distorting and partly demagnetizing.
Is armature reaction of alternator at lagging zero power factor purely demagnetising?
So, it can be concluded that, field flux φ f leads E by 90 o. Therefore, armature flux and field flux act directly opposite to each other. Thus, armature reaction of the alternator at lagging zero power factor is a purely demagnetising type. That means, armature flux directly weakens main field flux.
What happens when an inductive load is connected to an alternator?
When an inductive load with zero lagging power factor is connected to alternator, the load current starts to flow through the armature conductors. The load current will be delayed by 90 0 and so the armature flux produced will also be shifted by 90 0 with respect to the poles.