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Electronics Forum / Design / July 2009Toroid for mains conversion?
I saw a site once that said toroids were much more efficient and much smaller in height then equivalent E-I type transformers. Why do we not see very many for mains conversion if this is the case? "Bob.Jones5400@gmail.com" >I saw a site once that said toroids were much more efficient ** False. The percentage efficiency of similar rated E-cores and toroiodals is the same. > and much > smaller in height then equivalent E-I type transformers. ** Makes them preferable in slim, rack style cabinets. However, a U-core transforemer is just as low in height. See pic: http://www.ecraftsmen.com/user_files/images/Image/450-VA-Single-Phase-Transforme r-sm.jpg >Why do we not > see very many for mains conversion if this is the case? ** Cos it is simply NOT the case - pal. Plus there are many drawbacks associated with toroidals. ..... Phil >>I saw a site once that said toroids were much more efficient > >** False. >The percentage efficiency of similar rated E-cores and toroiodals is the >same. They are less leaky. It stands to reason that any difference, even if too small to consider major, would be in favor of the toroid. "Dorothy with the Red Shoes on"... "Phil Allison" >>>I saw a site once that said toroids were much more efficient >> [quoted text clipped - 3 lines] > > They are less leaky. ** ?????????? > It stands to reason that any difference, even if > too small to consider major, would be in favor of the toroid. ** For the same VA rating, percentage efficiency ( under load) can go either way, by small margins. The subject is MAINS power toroidals BTW. ..... Phil > "Dorothy with the Red Shoes on"... > "Phil Allison" [quoted text clipped - 16 lines] > > The subject is MAINS power toroidals BTW. And toroids are a pain in the a.s to wind. Even if you have a machine doing it, it's still a pain in the a.s because the machines require a much greater degree of care and feeding than a simple wire winding lathe putting turns on a bobbin. (You can figure this out on your own if you consider what the machine has to do. I used to know a guy who had to maintain both types, and the toroid-winding machines were _always_ broken). So: you get an itty bitty bit more efficiency -- maybe -- and you have to deal with much more finicky machines on your production line. This probably explains why there are a few toroidal mains power transformers out there, but not a whole lot of them.  Signaturewww.wescottdesign.com "Tim Wescott is a f.cking LIAR " Phil Allison wrote: >> "Dorothy with the Red Shoes on"... >> "Phil Allison" [quoted text clipped - 18 lines] > > And toroids are a pain in the a.s to wind. ** Idiot, emotional opinon - not fact. > So: you get an itty bitty bit more efficiency -- maybe -- and you have to > deal with much more finicky machines on your production line. ** The efficiency claim is bogus and irrelevant in any case - since consumers always pay the electric bill. Less weight, low profile, very low external field, very low off load current draw (ie Imag) and very low leakage inductace are unique advantages. The dollar cost is the same or less. So PISS OFF - you pig ignorant moron. ..... Phil > "Tim Wescott is a f.cking LIAR " >So PISS OFF - you pig ignorant moron. Oh Phil, you having been doing so well. I was thinking we should have a celebration party for you. Mike > "Tim Wescott is a f.cking LIAR " > [quoted text clipped - 38 lines] > > So PISS OFF - you pig ignorant moron. And here I was agreeing with you and expanding a bit. Are you saying, then, that _anyone_ who agrees with you is a -- well, it's your language, I'll leave it to you. Do get back on your meds, you're a pleasant addition to the group when you're not foaming at the mouth. Signaturewww.wescottdesign.com >> "Dorothy with the Red Shoes on"... >> "Phil Allison" [quoted text clipped - 30 lines] >This probably explains why there are a few toroidal mains power >transformers out there, but not a whole lot of them. I found it entertaining... that last ground isolator (Xitel) I bought used ferrite pot core transformers for audio... and the bass response is excellent! ...Jim Thompson | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine Sometimes I even put it in the food >> "Dorothy with the Red Shoes on"... >> "Phil Allison" [quoted text clipped - 30 lines] > This probably explains why there are a few toroidal mains power > transformers out there, but not a whole lot of them. Isn't the object of a torroidal transformer greater isolation and less radiated energy? Bob On Jul 2, 8:30 pm, Dorothy with the Red Shoes on <Doro...@notinkansas.org> wrote: > >>I saw a site once that said toroids were much more efficient > [quoted text clipped - 4 lines] > They are less leaky. It stands to reason that any difference, even if > too small to consider major, would be in favor of the toroid. In the bad old days when I had to work for a living I had a rule of thumb for power transformers. 1) if the signal resolution was greater than 500uV use the general purpose laminated transformers. 2) if the signal resolution was between 50uV and 500uV use an enclosed transformer Google hammond 167 series transformer 3) if the signal resolution was below 50uV use a toroid Google toroidal transformer magnetic field leakage Open frame transformers can induce loop currents in the metal chassis. This can give you all sorts of low level errors that appear and disappear if the chassis moved or another chassis is placed close to it. >On Jul 2, 8:30 pm, Dorothy with the Red Shoes on ><Doro...@notinkansas.org> wrote: [quoted text clipped - 21 lines] >disappear >if the chassis moved or another chassis is placed close to it. That's ARRL type stuff... and true. > "Bob.Jones5...@gmail.com" > [quoted text clipped - 21 lines] > > ..... Phil http://www.eea-trafo.com/toroidal.html "Toroidal transformers typically are 90 to 95 per cent efficient; whereas E-I laminates have a typical efficiency of less than 90 per cent." Of course they do not mention anything about mains/low frequency but since they don't mention the frequency dependence I'd assume it is the general case. After all the reason why E-I is less efficient is because of the geometry which is probably frequency independent. "Bob.Jones5400@gmail.com" "Phil Allison" > >I saw a site once that said toroids were much more efficient > [quoted text clipped - 17 lines] > > Plus there are many drawbacks associated with toroidals. http://www.eea-trafo.com/toroidal.html "Toroidal transformers typically are 90 to 95 per cent efficient; whereas E-I laminates have a typical efficiency of less than 90 per cent." ** Complete pile of MARKEING bullshit !! Lots of it to be found on the web - fool. So do not use it as FACT !!! ..... Phil ..... Phil >http://www.eea-trafo.com/toroidal.html > >"Toroidal transformers typically are 90 to 95 per cent efficient; >whereas E-I laminates have a typical efficiency of less than 90 per >cent." You'd best take those efficiency figures with a grain of salt, also any claims to permissible operating flux level differences attributed to the structural differences alone. Efficiency is something you can pay for, but are unlikely to be more willing to do so than anyone else. Any road - if your concern is with audio frequency transformers, as stated elsewhere, efficiency will hardly be your first consideration. RL >> "Bob.Jones5...@gmail.com" >> [quoted text clipped - 32 lines] >general case. After all the reason why E-I is less efficient is >because of the geometry which is probably frequency independent. I know that, for some reason, European consumers LOVE toroidal transformers in products... Enough so that they might gravitate towards a product with a toroid xformer rather than one with-out a toroidal xformer. Since theyre tape wound, you don't have the round the corner magnetic grain path problem that you do with E-I lams. Maybe that's why ? But how would they even know this or care much ? You still have to get the wires out of the windings... This is where they tend to "leak", field wise AFAIK. bob > I saw a site once that said toroids were much more efficient and much > smaller in height then equivalent E-I type transformers. Why do we not > see very many for mains conversion if this is the case? Cost, you can wind 10 EI or U cor transformer bobbins at once. ( right off the wire spools ) A toroid can only be done one at a time. (unless the machine can handle more than one) A shuttle needs to be wound for each toroid. toroid winding equipment cost more. They do offer benefits, but the added cost is not justifiable in most cases. Cheers "Martin Riddle" > "Bob.Jones5400@gmail.com" >> [quoted text clipped - 8 lines] > A shuttle needs to be wound for each toroid. toroid winding equipment > cost more. ** Against that are facts like: 1. C-cores come ready to use, instead of a box full of lams to be assembled after the bobbin is fully wound and terminated. 2. C-core winding is very fast, inclding all the layers of plastic wrap. 3. The winding wires can also be used to form the terminations in many cases. 4. No metal mounting frames or bolts need be fitted by hand to assemble the final product. 5. No resin coating or baking in an oven is needed to excluded moisture or make all the lams stick together. Fact is, that in the majority of VA sizes and styles, a toroidal tranny takes LESS time to complete than E-core types and uses less materials. ..... Phil > "Bob.Jones5...@gmail.com" <bob.jones5...@gmail.com> wrote in message > [quoted text clipped - 15 lines] > > Cheers This sounds like a much more reasonable answer. "Bob.Jones5400@gmail.com" This sounds like a much more reasonable answer. ** Hey listen - DICKHEAD !!!! YOU are in NO position to judge the answers. Cos YOU are a know nothing w.nker. ..... Phil > "Bob.Jones5...@gmail.com" > [quoted text clipped - 7 lines] > > ..... Phil So I'm suppose to listen to some retard who acts like an expert and claim he is an expert just because he wants to be an expert? You have the proof by authority down pat! Don't get me wrong. I'm sure your a genius. This is quite comical. You get all upset cause someone doesn't take your drool as gospel. Your proof humans haven't evolved very far from apes. "Bob.Jones5400@gmail.com "Phil Allison" > This sounds like a much more reasonable answer. > [quoted text clipped - 3 lines] > > Cos YOU are a know nothing w.nker. So I'm suppose to listen to some ... ** No need for anyone to simply *believe* anything I post. Politely ask me for the REASONS and I *will* supply them. But PITA trolls like you NEVER ask for reansons - cos they know it will all go right over your head. YOU do not even know what transformer "efficiency " IS nor how to quantify it nor if it is a variable or fixed number. So piss off - dickhead. ..... Phil > "Bob.Jones5...@gmail.com > "Phil Allison" [quoted text clipped - 23 lines] > > ..... Phil Keep telling yourself that. There is an obvious need you have to get people to believe you and believe you are a genius. This is a sign of insecurity. We are all insecure but some of us are intelligent to deal with it properly. > > "Bob.Jones5...@gmail.com > > "Phil Allison" [quoted text clipped - 28 lines] > insecurity. We are all insecure but some of us are intelligent to > deal with it properly. Phil is well known, and mentally ill. You are wasting your time arguing with him. SignatureYou can't have a sense of humor, if you have no sense! On Jul 3, 9:24 am, "Bob.Jones5...@gmail.com" <bob.jones5...@gmail.com> wrote: > > "Bob.Jones5...@gmail.com > > "Phil Allison" [quoted text clipped - 28 lines] > insecurity. We are all insecure but some of us are intelligent to > deal with it properly. I've designed using toroidal's, 5VDC => 180VDC PCB, with the toroidal being a step-up. The oscillator fedding the primary can be of a higher frequency to reduce the size of the X-former, however, at higher frequencies the EI type begin emitting EMF, I guess due to the corners, so the toroidal should be better in that application. At 60 hz primary the EMF emissions are likely nil (?). Ken "Bob.Jones5400@gmail.com" ** You are DEAD MEAT - you stinking cunthead. No matter where you post. .. Phil > Keep telling yourself that. There is an obvious need you have to get > people to believe you and believe you are a genius. This is a sign of > insecurity. We are all insecure but some of us are intelligent to > deal with it properly. Phil's problem is not ego, it's some sort of mental illness. He actually knows a fair amount of engineering, so cut him some slack. Cheers Phil Hobbs >I saw a site once that said toroids were much more efficient and much > smaller in height then equivalent E-I type transformers. Why do we not > see very many for mains conversion if this is the case? Cost Bob >>I saw a site once that said toroids were much more efficient and much >> smaller in height then equivalent E-I type transformers. Why do we not [quoted text clipped - 3 lines] > >Bob Switchers. John "John Larkin" "Bob.Jones5400@gmail.com" >>>I saw a site once that said toroids were much more efficient and much >>> smaller in height then equivalent E-I type transformers. Why do we not >>> see very many for mains conversion if this is the case? >> > Switchers. ** Aside from the fact the OP's information is WRONG - I suspect he can tell a SMPS from an iron core transfomer PSU. The Q is why do you see far more E-core than toroidals in commercial equipment, given the oft claimed "efficiency" and size advantage of the latter ? ..... Phil >"John Larkin" >"Bob.Jones5400@gmail.com" [quoted text clipped - 11 lines] >equipment, given the oft claimed "efficiency" and size advantage of the >latter ? Switchers are getting more common as they get cheaper and include PFC. The great advantage is the continuous 100-240 volt input range. I buy a PF-corrected Mean Well 150 watt switcher (48 volts DC out) for about $38. Has all the UL and CE stickers. No failures so far. I can't buy a 150 watt toroidal transformer for that, much less the rectifiers, caps, line-voltage-switch stuff. John "John Larkin" ** Completey off with the faries. And the dopes. <jjSNIPlarkin@highTHISlandtechnology.com> wrote in message news:kees45pegmo58a6pacguu91otujulf019o@4ax.com... >>"John Larkin" >>"Bob.Jones5400@gmail.com" [quoted text clipped - 22 lines] > > John >"John Larkin" > >** Completey off with the faries. > > And the dopes. Afraid of switchers? Lots of people are. One project I want to do would series 8 of the 48-volt switcher outputs to make a 400 volt supply. All I need is a customer for it. John >I saw a site once that said toroids were much more efficient and much > smaller in height then equivalent E-I type transformers. Why do we not > see very many for mains conversion if this is the case? The only toroidal transformers I have seen are in high end low level audio equipment. Bob <castlebravo242@att.net> > The only toroidal transformers I have seen are in high end low level audio > equipment. ** Then you have seen sweet f.ck all audio gear. Cos the majority of high powered amplifiers used in pro-audio have toroidal transformers. .... Phil >>I saw a site once that said toroids were much more efficient and much >> smaller in height then equivalent E-I type transformers. Why do we not [quoted text clipped - 4 lines] > >Bob 'high end' 'low level' How retarded. >>I saw a site once that said toroids were much more efficient and much >> smaller in height then equivalent E-I type transformers. Why do we not >> see very many for mains conversion if this is the case? > >The only toroidal transformers I have seen are in high end low level audio >equipment. I see 'em all the time in Rohde & Schwarz test equipment. > >>I saw a site once that said toroids were much more efficient and much > >> smaller in height then equivalent E-I type transformers. Why do we not [quoted text clipped - 4 lines] > > I see 'em all the time in Rohde & Schwarz test equipment. Some old monochrome computer monitors used them as well. It allowed them to use a smaller & thinner case. SignatureYou can't have a sense of humor, if you have no sense! >>I saw a site once that said toroids were much more efficient and much >> smaller in height then equivalent E-I type transformers. Why do we not >> see very many for mains conversion if this is the case? > > The only toroidal transformers I have seen are in high end low level audio > equipment. I saw one in a (driveway) gate closer controller. (step down transformer for the logic board and the motor) >>I saw a site once that said toroids were much more efficient and much >> smaller in height then equivalent E-I type transformers. Why do we not [quoted text clipped - 4 lines] > > Bob I've got one in a low voltage lighting fixture. The only reason I can see for its use is that it provides a somewhat lower profile than would a 'standard' configuration core. SignaturePaul Hovnanian paul@hovnanian.com ---------------------------------------------------------------------- Have gnu, will travel. > I saw a site once that said toroids were much more efficient and much > smaller in height then equivalent E-I type transformers. Why do we not > see very many for mains conversion if this is the case? Co$t. |
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