// Does the flux in transformer core increases with load ?

# Does the flux in transformer core increases with load ?

In a transformer, the flux in the core does indeed change with the load, and this phenomenon is fundamental to the operation of transformers. To understand how the flux varies with load, let’s delve into the working principles of transformers and explore the relationship between flux and load.

### Working Principles of Transformers:

1. Mutual Induction:
• Transformers operate based on the principle of mutual induction. When an alternating current (AC) flows through the primary winding of the transformer, it produces a changing magnetic field around it.
2. Induced EMF:
• This changing magnetic field induces an electromotive force (EMF) in the secondary winding according to Faraday’s law of electromagnetic induction. The induced voltage in the secondary winding is proportional to the rate of change of magnetic flux.
• The magnetic flux produced by the primary winding links with both the primary and secondary windings. The concept of flux linkage refers to the magnetic flux passing through a coil, considering the number of turns in the coil.

1. Ideal Transformer:
• In an ideal transformer (one with no losses and perfect coupling between windings), the magnetic flux in the core is primarily determined by the applied voltage and the number of turns in the windings.
2. Relationship with Voltage:
• The core flux (ΦΦ) is directly proportional to the voltage applied to the primary winding (��Vp​) and inversely proportional to the number of turns in the primary winding (��Np​). Mathematically, this can be expressed as: Φ∝����Φ∝Np​Vp​​.
• When a load is connected to the secondary winding, it draws current. The load impedance (�Z) affects the current flowing through the secondary winding. The relationship between current (�I), voltage (�V), and impedance (�Z) is given by Ohm’s law: �=��I=ZV​.
4. Current in Primary Winding:
• The current in the primary winding is related to the secondary current by the turns ratio: ��=����⋅��Ip​=Np​Ns​​⋅Is​, where ��Ip​ is the primary current, ��Ns​ is the number of turns in the secondary winding, ��Np​ is the number of turns in the primary winding, and ��Is​ is the secondary current.
5. Impact on Flux:
• The primary current affects the magnetic field in the core, and as a result, it influences the magnetic flux. An increase in load current leads to an increase in primary current, which, in turn, affects the magnetic flux.
6. Saturation Consideration:
• It’s important to note that the magnetic core material has a saturation point beyond which an increase in current may not result in a proportional increase in flux. Saturation limits the maximum magnetic flux that the core can handle.