Why is air gap crucial for magnetic circuit?

Air-gap is one of the most crucial part of magnetic circuits, especially in high power inductors. It significantly modifies parameters of magnetic devices by increasing of saturation current, linearizes B-H curve of magnetic circuit and causes decreasing of the inductance.

What is gapped core?

What is a gapped core? In an ordinary inductor core the magnetic flux lines are guided all the way round the windings by way of the ferromagnetic material in the core. However, in a gapped core a small section of the flux path is replaced by a non-magnetic medium – such as air.

Why the OC test is normally done on the LV side?

Why OC test is performed on LV side? Explanation: Open circuit test can be performed on any side but for our convenience and supply voltage available we generally conduct the test on LV side, to get corresponding parameters on HV side we can use transformation ratio. Current by voltage will give net admittance. 6.

What happens when you include an air gap in a ferrite core inductor?

When you add an air gap to increase the reluctance of the core then it is almost as if you have decreased its permeability, and thereby lowered the inductance of a winding on it. Adding the gap therefore spoils the inductance.

What is the minimum air gap?

The minimum required air gap shall be twice the effective opening of a potable water outlet unless the outlet is a distance less than three times the effective opening away from a wall or similar vertical surface in which cases the minimum required air gap shall be three times the effective opening of the outlet.

Why do we add an air gap to a flyback transformer?

Adding an air gap to the the flyback transformer increases the reluctance of the magnetic circuit. Doing this does a few things: Decreases the effective permeability of the core Decreasing permeability (also decreasing inductance) increases the amount of current that can be supplied to the transformer before saturating.

Why iron core is used in transformer in place of air core?

The ability of iron or steel to carry magnetic flux is much greater than air. This ability to carry flux is called permeability. Thus iron core is used in transformer in place air core. Modern electrical steels have permeabilities in the order of 1500 compared with 1.0 for air.

What is the purpose of a gap in a transformer core?

The increase in the magnetizing current between nongapped and gapped cores is clearly shown by projection from the intercepts on the B/H loops. Thus, in the transformer example, the gap is used to reduce the inductance (perhaps for resonant applications).

What happens when you add an air gap to a core?

Remember why you use a core in the first place: to raise the inductance of your windings. When you add an air gap to increase the reluctance of the core then it is almost as if you have decreased its permeability , and thereby lowered the inductance of a winding on it.