Transformer efficiency - Z-11,H-14, c-core, r-core , toroidal

[flyboi]

High guys!


Need your pointers on the percentage of efficiency for the different type of transformer core. I've tried to search it in this forum n google it from the internet, but so far I only managed to find that toroidal has about 80-90% efficency n R-core has a better efficiency than the toroidal. I just need a percentage of efficiency for Z-11, H-14 n C-core transformer coz I plan to order a transformer for my power amp project. Just don't wanna make a mistake of ordering one n at the end found out that I've made a mistake of ordering a lower value one bcoz I did not take into account about the transformer lost of efficiency. Hope u guys can share some infos. Thanks!



Cheers!

Eddy.

[mzzj]

Originally posted by flyboi
High guys!

Just don't wanna make a mistake of ordering one n at the end found out that I've made a mistake of ordering a lower value one bcoz I did not take into account about the transformer lost of efficiency. Hope u guys can share some infos. Thanks!

Cheers!

Eddy.

Umm, what is your problem? If you order 300VA trafo it outputs 300VA no matter if its 80% or 99% efficient. ?
BTW. Toroids can be custom-ordered for higher effiency also.

[mzzj]

Its hard to believe that R-core could have higher effiency than toroid. Sure either of these types can show higher effiency if different materials or different amounts of material are used. For example reducing core losses and using more copper for wiring effiency can be improved, but this increases price drastically.

[flyboi]

Originally posted by mzzj

Umm, what is your problem? If you order 300VA trafo it outputs 300VA no matter if its 80% or 99% efficient. ?
BTW. Toroids can be custom-ordered for higher effiency also.

Hi mzzj!

Thanks for your reply. Actually i'm very green on this subject n need a clarification. From your explanation, let's say if the trafo has 60% efficiency, the output will still be 300va. But bcoz of total lost of 40% in efficiency, wouldn't it perform like a 180va trafo? So, based on your explanation, a 300va trafo will still have a sonic or performance of a 300va transformer eventhough it hast lost 40% efficiency. If that is the case, I should not be to worry about efficiency then. Thanks!

Originally posted by mzzj
Its hard to believe that R-core could have higher effiency than toroid. Sure either of these types can show higher effiency if different materials or different amounts of material are used. For example reducing core losses and using more copper for wiring effiency can be improved, but this increases price drastically.

This is what I found during googling lastime. So, I must be wrong. Thanks for the highlights.


Cheers!


Eddy.

[mzzj]

Originally posted by flyboi


Hi mzzj!

Thanks for your reply. Actually i'm very green on this subject n need a clarification. From your explanation, let's say if the trafo has 60% efficiency, the output will still be 300va. But bcoz of total lost of 40% in efficiency, wouldn't it perform like a 180va trafo? So, based on your explanation, a 300va trafo will still have a sonic or performance of a 300va transformer eventhough it hast lost 40% efficiency. If that is the case, I should not be to worry about efficiency then. Thanks!


This is what I found during googling lastime. So, I must be wrong. Thanks for the highlights.

Cheers!


Eddy.

Transformers are rated by output power, so 300VA transformer can supply 300VA no matter what effiency. Difference is how much power that transformer is drawing from wall outlet. 300VA transformer with 60% effiency needs 500VA from outlet, and 90% efficient transformer takes 330VA. But amplifier have same 300VA availlable in both cases.

Googling is highly recommended, but when it comes to audio-related stuff you have to assume that 80% of information is snakeoil and BS.

[mzzj]

Originally posted by flyboi


I just need a percentage of efficiency for Z-11, H-14 n C-core

Cheers!

Eddy.

C-core, R-core and Toroidal are shapes of core.
Z-11 and H-14 are different types of silicon steel material that can be used in any shape of core. Z-11 is better and more expensive material than H-14.

[Tweeker]

O-core is the most efficient core shape.

[NickC]

Efficient is often attribute to design
Z11, h14,m19 are transformer grade which just reflects the core loss at 1.5 T. Z11 is 1.6W, h14 and m19 are 3.5w.
Maximum T for z11 is 1.75 to 1.8(high B). While h14 and m19 is 1.6

In reason times transformer designers have often increase this T figure to say 1.1 T for m19 and higher for the m6/z11 series. This way they can pack more va into the same trans. However this inturns reduce the efficiency of the design. But due to rising more like sprinting markets in india and china. Shipping cost needs to be reduce Thus making transformer design less efficient just to save weight. Amp manufactures like sony and others, find that their biggest cost is the transformers. It weights down their amp to much.

What happens this states that z11 is able to take higher T thus allowing more overloads. What happens when the mag field goes close/ than bigger than maximum T for the material, the material cant hold the magnetic field and start to emit lots of mag field.
what happens is that All transformer whether c,ei, o(toroidal), r will always emit this mag field.

However do note ei mag field is radiating along the axis of the copper wire while r and o emit this field within its hole thus preventing spraying of mag field everywhere.

In our normal practice when making audio transformers, we specify our designs of Z11/m6 to run at 1.05 T to reduce power loss. Eff of up to 90% is acheivable. This inturns sacrifies lots of va in return for efficient. Being an audio fan. I have studied that lowering the va and bring up eff is offten very beneficial to audio. THe music just flows better period. It often pays to get custom wound trans for an audio transformer winder. The benefits is often more inreturns than a blackgate, no run in requires just the big jump in performance. Being custom allows the insertion of E.static screen which is so beneficiary in audio. Everything is quieten down due to this

Also in reason time toroids vs EI core question has often come up. I believe at lower va say 10-300va standard toroids have a better edge over standard EI. However everything above 300va some how EI just have the music in hand. This is because they require less current when turning on, don't saturate with dc involve unless excessive. This result is thru blind testing. So no maths involve to prove other wise. Most Japs, avoid the use of toroids and often still stick to EI core transformer due to this .

When custom making smaller trans ask the vendor to spec the mag field to 1.05T to 1.08T with e.static screen and goss shield and you will see it beating the run of the mill toroids in this class

Hope this info helps to clear some doubt.
Nicholas
PromitheusAudio

[Tweeker]

There is a type of toroidal core where the section is circular rather than rectangular in area. Its the toroid version of the r-core.

O-core.

[davidsrsb]

Transformer effiency depends on the power rating, low power are typically very poor.
The guage of copper used is also in there.

Cheap transormers are rated at 230V and are entering saturation at 240+, getting hot.

Basically you get what you pay for.