what my professors and textbooks told me 30 years ago ... 40% more efficient than EI type ...
Honestly speaking, I refuse to doubt you.
based on the post, the toroid can have as high as 96%, and toroid is 40% more efficient than EI. doing the math, this puts the EI core at about 69%.
If it is power efficiency you are talking about, this is easy
Pout
eff = ------------- x 100
Pin
(do you remember your textbook?)
And transformer (EI or torroids) are basically efficient motors averaging more than 90% in efficiencies. 69% efficiencies are worse than motors’ efficiencies averaging 70-80% - and this is simply not true!
Our 3-phase HV adaptation transformers on our new 160KVA UPSs are not torroids. I look up at the post beside out building and really, I wonder whether it has an oil-cooled torroids inside it. I peek in the substation beside the former Manuela in EDSA/SHAW – could it be torroids in there? Honestly, I don’t know. I have to confirm with my brother in Meralco to verify it for me, and will report it back to you.
If you mean by efficiency as the amount of material you put into it vis-à-vis the power output, probably you are right
– but power losses, no, you’re not (they average basically the same as torroids)! SO this should clear that cloud of your ‘so called’ efficiency.
Toroidal Transformers employacylindrical core wound with a copper wire. This transformer does not suffer from magnetic fluxleakages which usually occurin the coil of thetransformer. Hence,thecoils of the toroidal transformers arecharacterized with higher efficiency,and there is no interference in operationby leakage fluxes originating in the coil.
The overall efficiency lies between the E-I core and the toroidal......The toroidal core has no air gap at all, and is therefore more efficient (magnetically speaking)
Because of their construction tape-wound toroidal transformers are more efficient and produce less acoustical and electromagnetic noise than standard E-I transformers.
The strip construction ensures that the grain boundaries are optimally aligned, improving the transformer's efficiency by reducing the core's reluctance. The closed ring shape eliminates air gaps inherent in the construction of an EI core
I will also ‘paste’ my source finding regarding the torroid performance in a sound gear – but will reserve it for now until I search my ‘mahiwagang baul’.
l chose the Plitron toroidal transformer because of its exceptional bandwidth: -3 dB at over 200 kHz, the result of high primary inductance (the good stuff) and low leakage inductance (the bad stuff-- kind of like HDL and LDL cholesterol)-- much better than can be achieved with a conventional EI transformer.
I probably could go on forever. But this is getting to be a bore.
Also, your tube DIYer – whats the purpose of his torroid, for power output or for audio output? if it is for power output, I dont know what the bandwidth has got to do with it!
If it is for audio output, oh well, its not my taste for amplification, sorry – but the tube amp need it by force, not by choice!
Don't worry ... i am not getting bored ... now I am having more fun !