Sage-Tips

Should the brushes of a loaded DC generator be placed along GNA?

Brushes should be placed where the direction of current are changes or production of zero e.m.f., under no load condition MNA and GNA coincides with each other.

What is meant by armature reaction explain how compensating winding and Interpoles are used to minimize the effect of armature reaction?

Interpoles Interpoles are similar to the main field poles and located on the yoke between the main field poles. They have winding in series with the armature winding. Interpoles have the function of reducing the armature reaction effect in the commutating zone. They eliminate the need to shift the brush assembly.

What are the types of armature reaction?

Types of Armature-Reaction

• Demagnetization of the stator field.
• The cross magnetization of the stator field.

What is armature reaction explain in detail?

Definition of armature reaction : a magnetomotive force set up by the current induced in the armature of a dynamo that results in altering as to both magnitude and direction the flux due to the field magnet.

What is geometrical neutral axis?

The geometrical neutral axis (GNA) is the axis that bisects the angle between the centre line of adjacent poles. The magnetic neutral axis (MNA) is the axis drawn perpendicular to the mean direction of the flux passing through the centre of the armature.

What is the meaning of magnetic neutral axis?

MNA (Magnetic Neutral Axis) may be defined as the axis along which no emf is generated in the armature conductors as they move parallel to the flux lines. Brushes are always placed along the MNA because reversal of current in the armature conductors takes place along this axis.

Which factor determines the difference between the types of armature windings?

2. Which factor determines the difference between the types of armature windings? Explanation: The armature windings are all connected to the commutator in the case of DC machines. Commutator is nothing but device which converts dc voltage to ac voltage.

What is GNA and MNA definition?

MNA (Magnetic Neutral Axis) may be defined as the axis along which no emf is generated in the armature conductors as they move parallel to the flux lines. GNA (Geometrical Neutral Axis) may be defined as the axis which is perpendicular to the stator field axis.

What is Interpole winding?

Interpoles, also known as compensation windings, are extra field poles “in-between” the main field poles, thus “interpoles”. (Not the same as INTERPOL the Intl. police agency.) It does electrically what advancing the brush angle does mechanically, only better.

What is the neutral zone in DC machine?

Neutral zones are those places on the surface of the armature where the flux density is zero. When a generator operates at no- load, the neutral zones are located exactly between the poles. No voltage is induced in a coil that cuts through the neutral zone.