Mutual Flux Vs Leakage Flux - How to reduced Leakage Flux? - Electronicsinfos

What are Mutual Flux & Leakage Flux?

When the transformer is under no load condition All primary Induced flux is passed through the iron core and links with secondary coils But when the transformer is in load condition it's reduced the magnetic path permanence results in some primary flux passing through the Air to complete the magnetic circuit. 

if we discuss an ideal transformer there is no magnetic leakage that occurs in the core but in cases of a Practical transformer, some flux passing through in the air to complete the magnetic circuit is called leakage flux.

Mutual Flux Vs Leakage Flux 

Mutual Flux

The flux which is linked to both windings is called Mutual Flux and produces the secondary voltage or back emf.

In general, the greater the amount of mutual flux that is transferred between the windings, the more efficient the transformer will be. This is because the mutual flux represents the portion of the magnetic field that is used to transfer energy from the primary to the secondary winding. 

However, excessive mutual flux can also lead to saturation of the magnetic core material, which can result in losses and reduced efficiency.

Leakage Flux

The Flux which is linked only to one coil is called Leakage Flux. The effect of leakage flux is the same as External reactance. In small Units, The reactance is small as compared to the winding resistance but in large units, the reactance value is 10 times higher as compared to winding resistance. 

On no load or light load, The MMF is small so we neglect the Leakage Flux but on high load, max current is flowing in the primary and secondary coils and produces high MMF which also increases the leakage flux.

Important Points

1. Leakage flux is only linked with one coil at a Time either primary or secondary.
2. Primary voltage provides supply to the reactive drops I1X1 or I1R1 and the same as I2X2 or I2R2.
3. In an actual Transformer, Primary and Secondary windings consist of One core to reduce the leakage flux.

How to reduce Leakage Flux?

There are different methods used to reduce the Leakage Flux which are 

Method of Reducing Leakage Flux

1. Making The T/F Window Long & narrow
2. Arranging The Windings Concentrically
3. Sandwiching The Both Windings
4. Using Shell Type Construction

Making The T/F Window Long & narrow

The window area h*w is always calculated w.r.t cross-sectional area of windings. To increase the reluctance path and height we decrease the leakage flux and the other method is to decrease the width to reduce the leakage flux. practically there is some ratio in h and w that is limited to 4.

h/w = 4 In the case of a Practical transformer

Mutual Flux Vs Leakage Flux 

Arranging The Windings Concentrically

To reduce the Leakage flux One method is used a concentric winding arrangement. In this method, we wind first low voltage winding(LWV) on the core and use insulation then wind high voltage winding(HVW).

Mutual Flux Vs Leakage Flux 

Sandwiching The Both Windings

In this method, we use the sandwich method first we wind primary winding and surround it with both sides in secondary windings. we used more sandwich sections we need high insulation in adjacent Sections.

Mutual Flux Vs Leakage Flux 

Using Shell Type Construction

In this method, we used a Shell-type transformer in which The winding is used on the inner side and the core is used on the outer side.

Mutual Flux Vs Leakage Flux 

Conclusion

In conclusion, Mutual flux is essential for energy transfer in transformers, as it links the primary and secondary windings, enabling electromagnetic induction.

Leakage flux, however, energy loss as it does not contribute to the energy transfer between windings but instead leaks into surrounding materials.

Faqs(Frequently Asked Questions)

What is Mutual Flux vs Leakage Flux?

Mutual flux is the magnetic flux that links both the primary and secondary windings of a transformer, contributing to its operation. Leakage flux, however, does not link both windings and is considered undesirable as it does not contribute to the transformer's functionality.

How we Reducing Leakage Flux?

Reducing leakage flux in transformers is crucial for improving efficiency and minimizing energy losses. Here are several methods commonly used to achieve this

• Proper Winding Arrangement
• High-Permeability Core Material
• Minimizing Air Gaps
• Improved Insulation
• Shielding Techniques
• Symmetrical Winding Layout
• Optimized Core Design
• Quality Manufacturing Practices

what is the purpose of Magnetic Shields ?

Placing high-permeability material shields around the windings can help confine the magnetic flux and reduce leakage.

What is Interleaved Windings? 

Interleaved windings is a specific arrangement of winding coils around a transformer core.In this arrangement, individual coils are stacked and separated by insulating barriers and cooling ducts.

How Vacuum Encapsulation reduce leakage flux?

Encapsulating windings in a vacuum or high-permeability material can reduce the air gap and confine the magnetic flux.

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