Transformer Core Saturation

[iamakda]

Dear all,

Could any one tell me in detail that what is the meaning of TRANSFORMER CORE SATURATION and how it works and how it happens?

I will be really really obliged.

Thanks.

[rievax_60]

Re: Transformer Core Saturation

Dear all,

Could any one tell me in detail that what is the meaning of TRANSFORMER CORE SATURATION and how it works and how it happens?

I will be really really obliged.

Thanks.

This link describes the fundamentals of magnetic saturation in a not too confusing way,
http://www.electronics-tutorials.ws/...ysteresis.html

Transformer cores can saturate for various reasons depending on the application type.
50/60Hz mains transformer cores will saturate with excessive primary winding "magnetizing current" flow. This "magnetizing current" is the current that flows through the primary winding's inductance before any load is connected to the secondary.
Excessive mains voltage or a drop in frequency causes an increase in this "magnetizing current" which can lead to core saturation, which in turn leads to a large drop in primary inductance and further increase in damaging current.

[iamakda]

Re: Transformer Core Saturation

This link describes the fundamentals of magnetic saturation in a not too confusing way,
http://www.electronics-tutorials.ws/...ysteresis.html

Transformer cores can saturate for various reasons depending on the application type.
50/60Hz mains transformer cores will saturate with excessive primary winding "magnetizing current" flow. This "magnetizing current" is the current that flows through the primary winding's inductance before any load is connected to the secondary.
Excessive mains voltage or a drop in frequency causes an increase in this "magnetizing current" which can lead to core saturation, which in turn leads to a large drop in primary inductance and further increase in damaging current.

Dear Rievax,
Thanks for the reply but could you also tell me what is the disadvantage if the core get saturated?

Thanks.

[iamakda]

Re: Transformer Core Saturation

Dear Rievax,

What dose core saturation exactly means? Does it mean after the core saturation no more flux can be passed ?

[rievax_60]

Re: Transformer Core Saturation

Dear Rievax,

What dose core saturation exactly means? Does it mean after the core saturation no more flux can be passed ?

It means that the core flux stops increasing with increasing primary "magnetizing current".
For transformers to work properly, the flux needs to be continuously changing.
Its the changing flux that causes voltage to be induced at the secondary winding.
Its important to say "magnetizing current", because "load current" has little affect on core flux.

[rievax_60]

Re: Transformer Core Saturation

Dear Rievax,
Thanks for the reply but could you also tell me what is the disadvantage if the core get saturated?

Thanks.

If its a mains transformer that has too much core saturation, the primary current can be high enough to burn out the winding.
If saturation happens in the ferrite core of a high frequency switch mode power transformer, a large and sudden current spike will flow through the primary winding and the power transistor driving it. I have seen this destroy the transistor on the first saturation occurrence. The transformer usually survives this.

[iamakda]

Re: Transformer Core Saturation

If its a mains transformer that has too much core saturation, the primary current can be high enough to burn out the winding.
If saturation happens in the ferrite core of a high frequency switch mode power transformer, a large and sudden current spike will flow through the primary winding and the power transistor driving it. I have seen this destroy the transistor on the first saturation occurrence. The transformer usually survives this.

Dear Rievax,

Thank you so very much for your last 2 replies...I really appreciate this.

[gautham]

Re: Transformer Core Saturation

It means that the core flux stops increasing with increasing primary "magnetizing current".
For transformers to work properly, the flux needs to be continuously changing.
Its the changing flux that causes voltage to be induced at the secondary winding.
Its important to say "magnetizing current", because "load current" has little affect on core flux.

Why does the "load current" not have any effect on core flux? If the load is partly inductive, will it no draw magnetizing current and cause magnetizing current to change in the primary?

[japlytic]

Re: Transformer Core Saturation

On a self-oscillating power supply (e.g. DC-AC inverter), I have read that the phase of the moon can affect its output frequency in the case of a particular Tripp-Lite inverter model.

[rievax_60]

Re: Transformer Core Saturation

Why does the "load current" not have any effect on core flux? If the load is partly inductive, will it no draw magnetizing current and cause magnetizing current to change in the primary?

While the transformer has AC voltage applied to the primary and is unloaded, the
alternating core flux is inducing voltage across the secondary as well as across the primary. This self induced primary voltage almost completely opposes the applied primary voltage, resulting in small current flow (magnetizing current).

When the secondary winding is loaded, the direction of the instantaneous current flow tries to cancel the core's magnetizing flux. This causes a drop in the primary's self induced voltage causing the primary to draw more current to maintain almost the same core flux.

I am not certain what happens with an inductive load.