Saturation in transformers.

The simple answer to your toroid question is this:

Saturation occurs when the excitation losses in the core
are excessive and reflect an excessive primary no load current.

The quantity that you are looking for is VA/lb. loss:

i.e If you experience any value over 10VA/lb. you are
in or approaching saturation.

For example: If your toroid weighs 4 lbs. and you had
40 VA, the primary no load current would be .3333Amperes.

That amount of current would occur at 16 kilogausse @ 60Hz.

Normally we do not design for any flux density higher than
14kilogausse, so these losses are not prohibitive.

I know that Patrick is going to bite his tounge at any flux
density over 10KG, but I design for the high volume world
where economics do come into play. Also, we use other
core materials in the 26Ga. non-oriented steel arena.
Most toroids are wound with thin, grain oriented steel.

Hope this helps.

Jerry
.

Relevant Pages

  • Re: Toroids for power transformers
    ... with NO LOAD. ... If the transformer has much inductance and low hysterisis ... If one buys a toroid with all the usual horrid problems most of them ... from the core. ...
    (rec.audio.tubes)
  • Re: Toroids for power transformers
    ... with NO LOAD. ... A loaded transformer passes much greater primary current ... If one buys a toroid with all the usual horrid problems ... from the core. ...
    (rec.audio.tubes)
  • Re: Saturation in transformers.
    ... >are excessive and reflect an excessive primary no load current. ... If your toroid weighs 4 lbs. and you had ... >core materials in the 26Ga. ... The excitation current is in phase quadrature ...
    (rec.audio.tubes)
  • Re: Smps Toroids on a Ground Plane
    ... Could I blanket my toroid with some foil and ground the foil? ... contained in the core. ... high dv/dt node at one end and a lower dv/dt node at the other. ... Placement of the high dv/dt pinshould be away from potential EMI ...
    (sci.electronics.design)
  • Re: Smps Toroids on a Ground Plane
    ... Could I blanket my toroid with some foil and ground the foil? ... contained in the core. ... high dv/dt node at one end and a lower dv/dt node at the other. ... Now I switch to that special winding technique.. ...
    (sci.electronics.design)