Lowest frequency of a transformer

[Crazymechanic]

Hi , I've been wondering about this one thing.
Well a transformer works on indcution , so a increase/decrease in voltage amplitude and/or periodical polarity reversal is needed to induce a current and voltage in the secondary.

Now if we leave the current reversal aside for a bit and look at the increase then highest point and then decrease of a waveform that " feeds" the transformer primary , I wonder what's the lowest frequency a transformer can still be able to work ?
The bigger the wavelength the longer it takes for the voltage to reach and then drop drom a certain level in one half period, but since we can also say that AC is just DC if looked at from a " point in time" perspective then since the time it takes for a very low frequency half wave to change is pretty long does the transformer secondary can still sense that?

Or maybe I should ask , what is the lowest rate of change in voltage/current that a transformer can still work with ?

 

[nsaspook]

Or maybe I should ask , what is the lowest rate of change in voltage/current that a transformer can still work with ?

What are the size limits of the transformer for the working frequency, house size, planet size or known universe size?
http://www.atltransformers.co.uk/pages/frequency.htm
http://www.electronics-tutorials.ws/transformer/transformer-basics.html

 

[Crazymechanic]

there are no limits of size , this is a theoretical question , I'm theoretically interested.

So if i get it right from the article you gave me , a transformer could work on dc if only for one thing , after a given amount of time , or the time it took for a given material and size transformer core to reach saturation , so if the core won't saturate then the transformer could transfer usable power , but I guess it's just late nad I got something wrong because a static magnetic field can't induce current can it ..?

 

[nsaspook]

It's the 'ideal' transformer model:

http://www.beigebag.com/case_xfrmer_1.htm
https://www.physicsforums.com/showthread.php?t=145290

 

[voko]

Theoretically, the minimal frequency of transformation is zero. Which is, of course, nonsensical in practice.

Practically, it is one the many parameters of a transformer that must be very carefully chosen for optimal performance. It is in the domain of electrical engineering, not theoretical physics.