How flux is created in a transformer?

Flux is magnetic flux or a magnetic field created in the iron core of the transformer by the AC current flowing in the primary winding. A constantly changing magnetic field created by the AC applied to the primary is the means by which an AC voltage and current is induced in the secondary winding of the transformer.

What is alternating flux?

The overall strength of a magnet is measured by its magnetic moment or, alternatively, the total magnetic flux it produces. Leakage flux results in energy being alternately stored in and discharged from the magnetic fields with each cycle of the power supply.

What causes the alternating current in a transformer?

Transformers work only with alternating current. That’s because it’s the change of the magnetic field created by the primary coil that induces voltage in the secondary coil. To create a changing magnetic field, the voltage applied to the primary coil must be constantly changing.

What current sets up an alternating flux in the core of a transformer?

When an alternating current (AC) generator supplies current to the primary winding of an unloaded transformer, its magnetomotive force (MMF) produces an alternating mutual flux (ɸm) in the core. This small current is called the exciting current. Its magnitude is about 3\% or less of the full load current.

Is flux constant in 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.

Why does a transformer flux flow through the core?

Transformers cores use ferromagnetic materials with a permeability much higher than the air. Their permeabilities vary with the flux density, and a given mmf produces a flux whose magnitude changes. Inside the cores, there are losses due to hysteresis and eddy currents, manifested in the form of heat.

Does alternating current have polarity?

Alternating current (AC) flows half the time in one direction and half the time in the other, changing its polarity 120 times per second with 60-hertz current. Though AC itself has no polarity, when AC electrodes are used on DC they usually operate best on one specific polarity.

Why does a transformer work with alternating current and not with direct current?

It is because transformer workes on the principle of electromagnetic induction i.e. it will work only with currents that produce varying magnetic field that will cut the conductors and induce emf (as alternating current does ) , but dc produces a constant magnetic field which can not cause induction statically .

What is the nature of flux produced in a transformer?

The nature of the flux produced depends on the nature of the current in the primary winding. Hence, when we pass alternating current through the primary winding, we get an alternating flux in the transformer. As current supplied to transformer coil is AC therefore flux induced is also alternating.

How does a transformer work?

We apply an alternating voltage at the primary side. This creates a flux inside the transformer core ( ). Some voltage is induced on the secondary side winding according to the Lenz’s Rule ( ). This voltage crates a current through the load ( ). And this current creates an opposing flux in the core ( ).

What is an exciting current in a transformer?

When an alternating current (AC) generator supplies current to the primary winding of an unloaded transformer, its magnetomotive force (MMF) produces an alternating mutual flux (ɸm) in the core. This small current is called the exciting current.

What is the magnetic effect of electric current on transformer?

As per Oersted’s theory which gives the Magnetic effect of Electric current; when current is passed through a conductor, it produces a magnetic field around the conductor. The same principle is applied in case of a transformer. When current is circulated through the primary winding of a transformer, it produces a magnetic field around it.