Toroid Trafo as choke

[flyinglemur]

Hey,

Rooting through the storeroom today produced a toroidal 20-0-20-0 PSU, which when metered across the mains inputs (115-0-115-0 wired for 230V), yields 7.2H.

Anyone else done similar, and if so, did you just insulate the original taps?

L

 

[kevinkr]

Toroids have very limited tolerance for dc on their windings, likely if you use it as a choke the core will saturate and you will be left with just the winding dc resistance. Not recommended.

 

[flyinglemur]

<200mA limited ? No harm giving it a shot and seeing what happens, have access to non-toroid as well, so just a matter of experimentation

 

[woody]

I have tested a transformer as a choke and a toriod autoformer
as a choke in a choke input power supply. I Iloaded them to ~80% of there ac current rating with darn good results.
I think my results were about 5% different than calculated using
Duncan's power suply designer. Now this may not work in all cases but in the 2 cases I tried it sure did.

 

[flyinglemur]

Ta! Not massive current here, so I think we're well within our reach, it's a 50VA trafo, so...looks to be okay