Table of Contents
- 1 Why armature reaction is not present in induction machines?
- 2 What is armature reaction in dc machines How can the effect of armature reaction be minimized?
- 3 What is armature reaction in DC machine?
- 4 Why do armature reactions occur?
- 5 What is an armature reaction in a DC machine?
- 6 What happens if both armature current and field current are present?
Why armature reaction is not present in induction machines?
In case of Induction Machine there is only one magnetic field is presence, i.e singly excited machine so there is not any armature reaction.
Is there armature reaction in synchronous motor?
The effect of Armature (stator) flux on the flux produced by the rotor field poles is called Armature Reaction. When the current flows through the armature winding of the alternator, a flux is produced by the resulting MMF.
What is armature reaction and how it affects the operation of a DC machine?
Armature reaction weakens the main flux. In case of a dc generator, weakening of the main flux reduces the generated voltage. Armature reaction distorts the main flux, hence the position of M.N.A. gets shifted (M.N.A. is perpendicular to the flux lines of main field flux).
What is armature reaction in dc machines How can the effect of armature reaction be minimized?
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 causes armature reaction?
The reaction caused by armature magnetomotive force is usually called armature reaction. The effect of armature magnetic field on the main magnetic field will distort the main magnetic field and produce armature reaction: The armature magnetic field distorts the main magnetic field, half strengthens and half weakens.
What is armature reaction and its effect?
Definition: The armature reaction simply shows the effect of armature field on the main field. In other words, the armature reaction represents the impact of the armature flux on the main field flux. The armature field is produced by the armature conductors when current flows through them.
What is armature reaction in DC machine?
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. The effect is the same for both lap- and wave-wound machines.
What is armature reaction What are the effect of armature reaction on synchronous machines at different power factors?
Lagging Power Factor Load:
| Sr. No. | Loading Condition | Effect of Armature Reaction |
|---|---|---|
| 1) | No Load | No effect |
| 2) | Unity Power Factor | Cross-magnetizing |
| 3) | Zero Power Factor Lagging | Purely demagnetizing |
| 4) | Zero Power Factor Leading | Purely magnetizing |
What is the effect 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.
Why do armature reactions occur?
The cross magnetizing armature reaction effect is mainly caused by armature conductors which are located under the pole arc. At high loads, this effect of armature reaction may cause excessive flux density in the trailing pole tip (in generator) and leading pole tip (in motor).
What is armature reaction and what are the effect of armature reaction?
What is armature reaction of dc machine?
The armature reaction is the effect of the armature flux on the main flux. In case of a DC motor the resultant flux is strengthened at the leading pole and weakened at the trailing pole tips.
What is an armature reaction in a DC machine?
In a DC machine, two kinds of magnetic fluxes are present; ‘armature flux’ and ‘main field flux’. The effect of armature flux on the main field flux is called as armature reaction.
What are the adverse effects of armature reactions on DC generators?
The adverse effects of armature reaction: Armature reaction weakens the main flux. In case of a dc generator, weakening of the main flux reduces the generated voltage. Armature reaction distorts the main flux, hence the position of M.N.A. gets shifted (M.N.A. is perpendicular to the flux lines of main field flux).
What is the armature reaction diagram for magnetic flux?
The armature reaction diagram is shown in the figure below. The armature flux produces some effects on the main field flux whenever the two fluxes get interacted. The effects produced on the main field flux are of two types. One is the effect that distorts the magnetic field and the other weakens the magnetic flux.
What happens if both armature current and field current are present?
If both armature current and field current is considered. The figure which depicts both the armature and field current is shown in the figure below. In this case, at ON-load both the armature and the field flux will act producing an armature reaction. Due to this, the resultant magnetic flux will not be uniform.
https://www.youtube.com/watch?v=30KTzBIiuo4