Machine Parts

When a current is flow through the armature conductor, a magnetic field is set up around the conductor. The interaction between this magnetic field flux and main field flux is called armature reaction.              The armature magnetic field has two effects- ·          If demagnetizer or weakens the main field flux. For the weakness of the main field flux the generated voltage is reduced. ·          It’s cross magnetizing component produces spark at the brushes due to the resultant field flux. Which is not in the same direction as the original main field flux but runs from the tip of one of the poles across the armature to the tip of the other pole.   Monocrystalline solar cell used in Smartphone                       Mechanism of Solar Collector for Flat Plate                            Why a self excited shunt generator will not build up voltage?     How can the voltage, current and power ratings of a generator be adjusted?

       Armature reaction : The current flow in the armature conductors of a dynamo has an important and undesirable effect upon the dynamo’s operation. The current in the armature produces a flux and it is the interaction between this flux and the field flux that is called   armature reaction.       Cross magnetizing and demagnetizing effect :   The effects of the armature flux   my be analyzed by considering the flux to consists of two components that are at right angle to each other as shown in fig. One component is at right angle to the field, and because this component crosses the main –field   flux, it is known as the cross –magnetizing component of the armature flux. The second component is in the same plane as the main field flux . The direction of this component is opposite to the direction of the main field flux, with the result the it tends to reduce the effect of the main field flux. This component of the armature flux , is known as demagnetizing component

In the shunt generator power furnishes to the load. As more devices are connected in parallel, the load on the generator increases; i.e. the generator current increases. Because the generator current increases, the terminal voltage    of the generator decreases. There are three factors that cause this decrease in voltage. Armature circuit resistance : When no current flows through the armature, there is no IR drop in the armature and the voltage at the terminals is the same as the generated voltage. But when there is current in the armature circuit a voltage drop exist due to the armature resistance, and the terminal voltage is less than the generated voltage. The terminal voltage may be calculated from the following equation: Vt =Eg-IaRa Armature reaction : When current flows in the armature conductors a flux surrounds these conductors. The direction of this armature flux is such that it reduces the flux from the field poles, resulting in both a reduced genera

Armature reaction:                                              When current flows in the armature conductors a flux surrounds these conductors. The direction of this armature flux is such that it reduces the flux from the field poles, resulting reduction in both generated voltage and terminal voltage. So we can say that the interaction between armature flux and field flux is called armature reaction. Effects on a loaded generator:                                                  When a load is connected to a generator, of course current flow exists. When current flows through a conductor a magnetic field is set up around the conductor. When several conductors are placed together, the flux from each conductor is combined to produce a resultant flux. The flux from the conductor on the left side of the armature and the flux from the conductor on the right side of the armature cause a resultant flux in the centre of the armature that is downward in direction. There