Understanding Ideal Transformers: Where Does the Flux Come From?

[noobish]

something i read from the textbook and i don't understand.

"in an ideal transformer, no magnetizing current is required to produce the flux"

so, where does the flux come from?

 

[Andrew Mason]

something i read from the textbook and i don't understand.

"in an ideal transformer, no magnetizing current is required to produce the flux"

so, where does the flux come from?

If the secondary is open there is no power drawn from the power source. But there is current in the primary. The current in the primary is the cause and result of the buildup and collapsing of the magnetic field in the primary (it is self perpetuating).

If the primary coil is a perfect inductor (in an ideal transformer R = 0) the current lags the voltage by 90 degrees. Since Power is $VIcos\phi = VIcos90 = 0$ the currrent does no work.

AM

 

[noobish]

TQVM. i think i understand it already.