Mell Why does the flux in the core remain constant even when the transformer is loaded?
Because a transformer is a constant flux device on any load and on any power factor. This is because of load component of current. In brief. As the load increase the primary current increase and cause more flux to flow through core so that the load could be satisfied.
How does the flux in the transformer remain constant from no-load to full load?
(b) Eddy current loss: Since flux in the core of a transformer is alternating, it links with the magnetic material of the core itself also. This induces an emf in the core and circulates eddy currents. The flux set up in the core of the transformer remains constant from no-load to full load.
Why flux is constant in a transformer?
Hence a transformer is always called a Constant Flux Machine. Because it follows the lenz’s law, for every change in flux density caused by loading on secondary, it will draw the magnetising current proportinately from primary. So, the net flux in the core is always constant.
How is the flux produced in transformer core is constant under all load conditions?
Any secondary load current will produce an extra current in the primary and these load-currents together produce NO NET FLUX, leaving just the magnetization flux i.e. it is constant under all load conditions.
What is constant in power transformer?
The power transformer is a constant flux device because it follows the Lenz’s law, for every change in flux density caused by loading on secondary it will draw the magnetizing current proportionately from primary. So, the net flux in the core is always constant.
How is the flux of a transformer determined?
It’s determined by mains voltage, frequency and primary winding inductance. If you connect a load to the transformer, the primary current will increase in a way to keep the core flux close to what it was without load.
How does the secondary leakage flux affect a transformer?
This flux also has its magnetic path in air and not in the core. The secondary leakage flux is proportional to the secondary current. There is a resulting reactance voltage drop in the secondary winding. Both the primary and the secondary leakage fluxes reduce the secondary terminal voltage of the transformer as the load increases.
What is the exciting current in a transformer?
When there is no load attached to the secondary winding, the current input to the primary winding usually ranges from 2% to 5% of the full-load current. The primary current at no load is called the exciting current. This current supplies the alternating flux and the losses in the transformer core.
How does the alternating flux affect the core?
As the magnitude of the alternating flux increases and decreases, the metal core is cut by the flux, as are the turns of the primary and secondary coils. Voltages are thus induced in the metal core and give rise to eddy currents. These eddy currents circulate through the core and cause I2 R loses, which must by supplied by the exciting current.