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How the losses will reduce if you keep the flux density in high level in power transformer?
The flux density is set at the most the core material can stand, which for standard laminated transformer iron is around 1 Weber per square metre. Based on that and the cross-section area of the core, the volts per turn figure is calculated for both the primary and the secondary winding. If the operating voltage stays constant, so will the flux density and the iron losses.
What is overfluxing relay?
A transformer is designed to operate at or below a maximum magnetic flux density in the transformer core. Above this design limit the eddy currents in the core and nearby conductive components cause overheating which within a very short time may cause severe damage. The magnetic flux in the core is proportional to the voltage applied to the winding divided by the impedance of the winding. The flux in the core increases with either increasing voltage or decreasing frequency. During startup or shutdown of generator-connected transformers, or following a load rejection, the transformer may experience an excessive ratio of volts to hertz, that is, become overexcited. When a transformer core is overexcited, the core is operating in a non-linear magnetic region, and creates harmonic components in the exciting current. A significant amount of current at the 5th harmonic is characteristic of overexcitation.
How the voltage is induced in a single phase transformer?
The changing magnetic flux in the iron core of the transformer induces a voltage in the windings.
How do you improve the flux linkage between the primary and secondary windings in a transformer?
by using an iron core
What is the significance of stepped core?
A transformer's windings are pre-wound around insulated 'formers' or tubes of circular cross section. To achieve maximum flux density, the core should ideally be of circular cross-section, too. A 'stepped core', then, describes the way in which the widths of the outer laminations of a transformer's core are progressively reduced ('stepped') in order to achieve a roughly-circular cross-section.
How the losses will reduce if you keep the flux density in high level in power transformer?
The flux density is set at the most the core material can stand, which for standard laminated transformer iron is around 1 Weber per square metre. Based on that and the cross-section area of the core, the volts per turn figure is calculated for both the primary and the secondary winding. If the operating voltage stays constant, so will the flux density and the iron losses.
Why is the purpose of using core in transformer?
To maximise the magnetic linkage and flux density between the primary and secondary windings.
What is the effect of operating a transformer on its rated frequency and at a higher voltage with no load current -hysteresis losses or eddy current losses?
A transformer is normally designed to work at a definite peak flux density in the magnetic core, which implies a fixed number of volts per turn (or turns per volt) for its windings, and this set by the cross-section area of the core. The peak flux density is a property of the core material, and this is taken into account by the transformer designer. When the transformer is operated at a higher voltage, the hysteresis loss in the core is higher, and if the flux density is higher than normal it means that the core losses increase quickly as the voltage is raised. So the no-load losses can be substantially higher, but a 20% increase in voltage can be tolerated for short periods. An exception to the above applies to European transformers designed for 50 Hz when used in North America on a 60 Hz supply. The 20% increase in frequency causes a 20% reduction in the flux density in the magnetic core, which means that the transformer can be used at a 20% higher voltage while running at the original peak flux density, and its power rating is 20% higher.
Where does hysteresis in a transformer depend on?
The power lost by hysteresis depends on the peak flux density in the core. If the transformer is getting hot even when on no load, it should be run at a lower voltage.
What is the function of the iron core in a transformer?
The iron core is there to provide a path for the magnetic flux to link both the primary and the secondary with as little flux as possible linking only one of the windings. The cross-section area of the core determines how much magnetic flux there is, because transformer iron has a fixed maximum flux density, usually 1 Weber per square metre. The amount of flux determines how many volts per turn there are on both windings.
What is the function of the core?
the function of core is to provide path to magnetic flux,a core may be armature core or may be transformer core
What is overfluxing relay?
A transformer is designed to operate at or below a maximum magnetic flux density in the transformer core. Above this design limit the eddy currents in the core and nearby conductive components cause overheating which within a very short time may cause severe damage. The magnetic flux in the core is proportional to the voltage applied to the winding divided by the impedance of the winding. The flux in the core increases with either increasing voltage or decreasing frequency. During startup or shutdown of generator-connected transformers, or following a load rejection, the transformer may experience an excessive ratio of volts to hertz, that is, become overexcited. When a transformer core is overexcited, the core is operating in a non-linear magnetic region, and creates harmonic components in the exciting current. A significant amount of current at the 5th harmonic is characteristic of overexcitation.
What is ac flux in transformer?
The flux means the flux of the magnetic field passing through the iron core of the transformer. Because the applied voltage is AC, it means that the flux is also AC. The voltage and the flux are related by the basic formula v = N d/dt (phi) where N is the number of turns in the coil. At a steady frequency this becomes: v = N x 2pi x freq x (total flux in Webers) This is the basic design equation for transformers because the peak flux density in the core sets a physical limit and determines the size of the transformer, which is why transformers are always larger at lower frequencies.
What is the purpose of transformer core?
yes core is usefull in transformer since it it increase the permeability for the flux (i..e,it offers less relucyance path thanj air ).Their by decresing the losses in the transformer.
Why in transformer core is necessary?
A transformer core is a low-reluctance magnetic circuit, which ensures that most of the magnetic flux generated by the primary winding links with the secondary winding. Without a core, little of the magnetic flux generated by the primary winding will link with the secondary winding.
How the voltage is induced in a single phase transformer?
The changing magnetic flux in the iron core of the transformer induces a voltage in the windings.
In transformer core flux depends on voltage whereas leakage flux depends on current?
In a Transformer, Core flux is the difference of primary flux and Secondary flux which are opposite to each other in direction. There difference is equal to the no load flux at all loads. So, some of primary flux passes through the core and remaining becomes leakage flux (Because Secondary flux forces it to get out of the core). Same is the case with Secondary flux. Now, flux is directly proportional to Voltage and Current. When Current increases due to increased load (and voltage remains same): Then both primary and secondary flux increase. Because both of them increase, so there difference remains same. And all remaining flux is forced out. Hence leakage flux increases with current, but Core flux remains constant. When Primary Voltage is increased: Then only primary flux increases. So difference of this new increased primary flux and previous same secondary flux increases. Hence Core flux increases with voltage, But leakage flux does not. That's how In transformer core flux depends on voltage whereas leakage flux depends on current.
