Winding Small Transformers For Smps

Here is how to wind small transformers for switching power supplies.

[@SatyajitRoy2048]

By far the best manual transformer making I have ever seen. Hats off to you!

[@mossvalebasketballau1513]

Excellent workmanship, I haven't seen transformers wound by hand with such presision and detail for us amateurs, Keep up your building skills in electronics.

[@chbonnici]

Prosit: First class explanation. People Like you make a difference

[@bradconnor3542]

you are great my friend, thanks a lot for such a wonderful info sharing dear, i hope to see more and more on smps from you, especially winding many type of AC/DC fly-back

[@crocellian2972]

Unbelievable skill and stamina. A true genius.

[@masarya8830]

Crocellian filem 17 tahun keatas .

[@fredriksjoblom5161]

to keep your wires side by side when you are winding a coil with several wires at once, try to take a piece of wood and drill a couple of small holes in it (max 1-2 mm) and drill the holes very close to each other, and before you start the winding you just thread a strand of wire through each hole and then you have a tool to keep the wires separated but still close to each other =D Thank you for this video. This was very useful information to me! If i did not watch this right now i would have been swearing and cursing sometime around 21.00 tonight when i would have been done wiring up my own SMPS transformer the wrong way!

[@supersilve]

Thanks for the tip

[@fredriksjoblom5161]

I'm just glad if i can help. Your teachings really saved me many many hours of work that would probably have been completely wasted if i did not't happened to watch this just before i was about to start winding an absolute catastrophe! I am on the last year of school to become an electrician. I can not meet you and discuss these topics but still you teach much better than many of my teachers, to me that is very impresive You are very good, not only at electronics but also teaching. Many people tend to forget this, but at least in my school i can clearly see that, sadly, the better our teacher is at electronics engineering the worse he is at teaching very often =)

[@ucupbintangtoedjoe4489]

@@fredriksjoblom5161 ea ea bisa juga dengan. Bahan plastik ga apa apa sing penting pokoke nyayur😁

[@TifinDragoshP-]

Good video! You should make a tool for many wires at the time. Using the nail is comfortable only with the thin wire by one . Thanks for the good video!

[@SLELECTRONICSCO]

work done well in a professional manner & explained well

[@1pcfred]

While I saw the winding machine in action I would have liked to have seen the operation of how the bobbin was mounted to it. I have an idea how it worked but seeing is knowing for sure. The video still gave me plenty to think about when it comes to winding transformers.

[@supersilve]

Please note that at the end of the treaded rod there is a brazed self tapping screw which will turn the spring that turns the counter. I can unwind the spring from the screw and the end of the rod will be free to be pulled back and gives me a chance to assemble the bobbin, I hope that helps.

[@1pcfred]

I was somewhat mystified about that one specific bit of hardware in your winder. To me it looked like a bit bent and chewed up smaller diameter threaded rod in the video. But now that you say I can see it being a spring too. Could almost be a piece of cable sheath? Like for a choke cable in a car, or lawnmower throttle cable. So thanks for the explanation.

[@stevekamala]

hi silivio nice job . good upload it is stewin of diysmps.

[@sethawuku1729]

This video is the best video ever great job Silvio

[@tedswimerr34]

Thank you for your excellent videos. I have learned much from your work!

[@aggpakelectrohobby]

Very helpful video.. ♥ Your winding machine is i like so much

[@ehimwenmataiwolouis1388]

Very nice job, keep It up sir

[@radoslavradoslavov3528]

Thank you very much! From your video i earned experince without any practice.

[@peep39]

Excellent video. Watching and learning

[@peep39]

Do you do your own PCB etching? That would be another good video

[@supersilve]

Yes I do my PCB etching. I use the iron method. There are a lot of videos on youtube regarding this subject.

[@peep39]

Thank you!

[@tacrom]

Very informative, thank you for taking the time to do this.

[@supersilve]

Thank you

[@worldentropy]

Nice work - goes to show what a pain in the proverbial winding transformers is, let alone SMPS ones. Question: why did you split the 6 wires for the first secondary layer across two pins? is it just a case of mechanics, and that soldering 6 wires on the same pin is difficult?

[@Made2hack]

Excellent video Silvio. A question in regards to secondary voltage. How do I determine the secondary voltage? Is it the same way as in regular low frequency transformer (for mains ie 50Hz)? How can I determine a stable 36V output on secondary? Do you have such calculations?

[@supersilve]

Hi to determine the secondary voltage depend on a few things as you know the mains fluctuates up and down and the secondary voltage will also. Due to the output voltage is rectified and smoothed with capacitors the resultant voltage will be the peak voltage. This in turn will sag under load to around 15 to 19% and tends to stabilize there. For constant voltage on the output you need to have feedback to the PWM to maintain it. Headroom in the secondary voltage must be left so that a constant output voltage with load and no load can be maintained. However more complex circuitry and calculations are necessary.

[@jimis04]

Thank you for posting this video as you promised!

[@chapterone2967]

Thanks a lot Silvio for nice and Detail video on winding smps transformer...I have question regarding the winding of the CT secondary winding...when create a CT you start from the top of the transformer and both winding have same direction.....i have read another tutorial from other source that CT winding should opposite direction between 1st wind and 2 wind of secondary to create CT

[@supersilve]

Yes its true what you said but using a bridge rectifier in the output will still work perfectly. If however it was a split winding using only 2 diodes then it should be done in the proper way. Start at pin to CT the second winding then start at CT and finish at pin.

[@chapterone2967]

Ok tnx a lot Silvio., noted that your project use bridge rectifier so CT WINDING direction does not matter.....but if using 2 diode one must wind the correct direction...in this case opposite direction between CT winding....

[@fabiolucca]

Excellent demonstration, I recently disassembled a transformer from a computer source and by what I thought the windings (mainly the primary) are undersized (too thin wiring), compared to what I learned in school for traditional transformers (60Hz Silicon Iron) 3A / mm. How do you do the sizing for toroids?

[@supersilve]

The current rating for the copper remains the same for iron and ferrite transformers. A few things may have to be considered but. If the ferrite transformer is cooled with a fan than we can squeeze more current for a given copper diameter. The duty cycle also has to be considered if for example the transformer in a smps runs say at 20% duty than the current rating can be increased. Let us say that the smps is used for an amplifier here for example we calculate for around 60% duty as music does not draw a constant load. I hope that helps you understand better.

[@fabiolucca]

@@supersilve Thank you again for responding, yes I came to think of the case of forced ventilation, and in the case of the duty cycle less than 100%, but in my case I will use up to 300W (85%) which is already enough and maybe make the reuse of the source and transformer since the source board data is not very accurate I'm not sure that it provides real promised 350W ... I applied the calculation you demonstrated and the number of turns turned out quite different from the actual (34 for (the core area is 1cm² and 33.3kHz) so that leads me to believe that my transformer was originally not scaled correctly or is considering low duty cycle. Note: Originally this source used for a 5V winding a copper blade instead of wire to avoid the skin effect and improve the stacking on the reel. Also used insulated copper blade between the primary and secondary attached appendages on one of the primary pins, I believe it serves to avoid interference. Pictures: computeiromaluco.tumblr.com/tagged/atx

[@supersilve]

Hi Fabio. Usually computer smps work around 20Khz and use a flux density of 2000 guass. If you still have the source at hand you can determine the switching frequency from the timing capacitor and resistor on the switching chip (usually a TL494). The switching frequency at the output is half of that on the timing of the chip. With known frequency you can make out the flux density used. The number of turns will also vary with the core material depending on its AL value. A higher frequency will get you more power for a given core. If you use 60-68Khz for example you will get 25% more power out of it. The wire size for this frequency must not be more than 0.5mm. Flux density 1600 guass. The copper screen is for safety as well as it is coupled via the HV ground and a small capacitor to earth ground. The 5v used a copper foil for better current handling thus a better CSA and less space. The CSA for copper wire used in ferrite transformers is 4A/mm² for continuous use. However if you use forced ventilation then 6 or 8A/mm² can be used but you may suffer a little voltage drop at full load. Remember that a computer does not work at full load all the time and usually it is around 50 to 60% duty cycle.

[@fabiolucca]

@@supersilve Hi, thanks again for the explanations are of great value to the community. Yes I have the Huntkey SMPS yet and I will use it for this transformer, I have done all the checks and modifications needed to use only the 12V over voltage voltage and overpower protection, and will include overcurrent, voltage and re-power the 12V line. This SMPS uses a C.I. similar to TL494 (KA7500) working at 33,333kHz. Soon I will redo the transformer and post the results.

[@fabiolucca]

@@supersilve Just out of curiosity, what insulation resistance do you consider minimum the transformer should have between primary and secondary? In my here it was around 212GΩ using 500V in the test (for one minute), which is very good ...

[@AIexanderHartdegen]

awesome video! I just wondering one thing. How do you calculate the idle current of your power supply, do you change the input frequency to keep a regulation or do you change the duty cycle? Thanks

[@supersilve]

The idle current depend on the flux density chosen this is usually between 1200 to 2000 guass. This also depend on the frequency of operation usually at 60Khz. The flux density (B) is around 1600 guass at 100Khz we use around 1200 guass. The variable frequency is used in special chips made for resonant power supplies, these vary frequency according to the load to maintain resonance and soft switching. Regarding regulation this depend on to control chip used, usually the pulse width is controlled to maintain a stable output voltage. Some headroom has to be left so that it can compensate for voltage drop during load ( Ex for regulation of 24v output the peak voltage for this has to be used thus 24 is multiplied by Sq root of 2 ) 34v.

[@AIexanderHartdegen]

thanks a lot for your help. I am making a home made car amplifier with PWM. This is why i am expecting some information about that. Thanks

[@yaghiyahbrenner8902]

I noticed ETD bobbins with terminals on opposite sides have doesn't have margins does this mean margins for these bobbins are not needed as the wingdings doesn't cross like the bobbin you have where terminals are all in one row.

[@nfg_racing7968]

Very informative videos on transformers I've been debating on winding my own high voltage Transformer for HV experiments what type of core would you recommend for a HV Transformer? I really wanna pull as much HV as possible from the 120V primary we have maybe 30KV - 40KV just not sure what core to start with I don't need a bunch of current but I do need some 100ma-500ma

[@supersilve]

High voltage is no easy task especially having square waves involved. Usually we divide the bobbin in sectoins to avoid arcing between windings. Some assumptions. 2000v at 500mA is already 1000w. If you need to calculate the current carrying capacity for copper wire then 3.35A per mm² for continuous rating. The amps per mm² will gradually increase if say the rating is 50% then 6A/mm². The core bobbin must be large enough to accommodate the windings and insulation needed. 40KV @ 100mA = 4KW. Are trying to kill yourself?

[@nfg_racing7968]

@@supersilve no no always safety first I'm trying to recreate tesla wardenclyff tower on a smaller scale of course but I just have a feeling I'm gonna need quite a bit of power from what I'm gathering looking over his patent for it I was thinking of running four NST in parallel and series that would give about 30kv at 120ma just not sure the transformers are gonna hold so I was looking in into building for the purpose but from researching its not as easy as I first thought there is quite a bit that goes into transformer design but for what I have gather so far a EE type core with the primary in the center and the secondary on the outer sections but I'm starting to think it's going to be quite a bit more work than I really wanna get into and MOT's I don't really think my house is set up for a bunch of them in series lol way too much current draw in reality there both dangerous but as long as I set up a safety protocol and follow it I'll be OK but thank you for the information I will definitely be subscribed and look forward to watching more videos and again thank you sir I appreciate your advice

[@supersilve]

@@nfg_racing7968 You can search for Diode gone wild on KZbin he made a tesla coil using MOTs.

[@nfg_racing7968]

@@supersilve thank you sir

[@nghiapham-ct1gf]

Great content, although the camera sometimes doesn't focus on where it needs to.

[@sethawuku1729]

Best video and good explanation keep up the good work 👌💪

[@supersilve]

Thank you

[@martinda7446]

That was a bit of art. Looked lovely...How did it perform? Subscribed.

[@supersilve]

The transformer performed very well. You can see the load test of the finished power supply on this Link kzbin.info/www/bejne/qJaWlHqLoJedbJI

[@supersilve]

Here is the power supply on test with the transformer that I showed . link kzbin.info/www/bejne/qJaWlHqLoJedbJI

[@jonathwyllams]

Silvio, your video is a great way to show me how can I do my transformer, but I'd like to know: can I use an old transformer of a computer supply to build this one? Thank you for share your knowledge 🙏

[@supersilve]

Yes you can use the old core from a computer power supply. The number of turns will differ according to the core size.

[@jonathwyllams]

@@supersilve Tks!!

[@audiokees4045]

Hi Silvio, I have a question for you as a expert on transformers. I need a resonant transformer with more then one output, I need multiply outputs, like 12 v 5 amp 350 volts 150 mA 2 x 120 volts 300mA and 2 x 65 volts 15 amps. I do not now how much this wil change resonant possibillities, I can not just use a normal smps because of EMI. with resnant (open loop) it will be low. I have not found any transformer calculator who can help, so whencalculate for 2 output voltages like 2 x 25 v 15 amp and put then in the others by hand I think resonance will go lower, but when I do use the big amps and voltage first the other has possible little impact,. Can you advice me what to do best? thanks in advance.

[@supersilve]

Trying to build an smps with all these voltages and different currents is quite a challenge. First of all the last output of 2 x 65v @ 15A That is nearly 2000w! I guess this should be a stand alone smps for this load and is the one that most likely to make EMI. This I guess is going to power a class A or AB amplifier. Here you should also use a pfc circuit to help out apart from resonant smps. Regarding other voltages which between them are of around 200w This should be a separate circuit (smps) built on the same pcb if you like but not suggested. These I am guessing you need for a tube preamplifier. The preamp supply needs to be filtered properly otherwise you will have problems. Please note that if using an smps for this may fit as well as the switching frequencies are beyond the audio spectrum. (20khz) using 50 or 60Khz will clear you of this, any harmonics will be well above. Coming to regulation of the output voltages a well designed pfc stage will help out a lot when using high power. For the high voltages I guess a resonant smps will regulate well considering the low power involved. Regarding the typology used is another question if using flyback or any other typology. The output can be regulated instead with the help of zener diodes and an opamp and opto couplers. It all depend what type of chip you are to use for the PWM. This will get rather complex and maybe out of our scope not being engineers. A lot of research and trials have to be made until a final good result is to be achieved. Good luck.

[@audiokees4045]

@@supersilve Thank your for the nice explaining of the problems I can face with this build, I have to say that the smps will be open loop because a feedback is by far not fast enough to regulate a amplifier load, all smps has this who is used for amps. without a resonance system for zvs switching EMI wil much higher, so the use of the resonance smps will do mucho better, I can also use 100 khz or more ferquencies, Gan is quite interesting by the way, busy to design a clas D open loop with it. A pfc circuit is not needed persé the reason is the peaks for the 65 volts 15 amps is just a fast transients with music, the big capacitors on the output of the transformer are the most importance these need low impedance, because of the smps frequenc y is 100 Khz or more the need of 10.000+ uF is not anymore needed as is with a normal supply. For the tube I can also use a other kind of smps like flyback, what is by the way also suggested to me. I can do a resonance version however that need a mosfet with very high voltage breakdown, it has high voltage peaks when switching. So for me, I need to use smps resonace type of smps and maybe Gan mosfets will do even better, these have no body diode where the trouble come from. So for short, the winding of transformers is a bigger challence with multiply voltages, a good software is the best way afcourse. When the smps is open loop and the resonance point right I get a quite stable voltage and no unstable behavior because of feedback who needs te be to fast for audio amp use, then things I hope get more easy. I set up a 220 volt ac save system with earthleak switch and go try and see what happens, I start with normal transformer for tube and furter from there. Thanks and Have a nice dag. kees

[@beakytwitch7905]

Tis an arcane craft indeed !

[@sajytvm4367]

Very interesting and informative. Thank you very much for your patience for the tedious work and good effort to share the experience with electronics enthusiastic like me. Just one doubt! I have seen in some of the SMPS transformers (100 to 200KHz)- a thin copper foil in between the high voltage layer and connected this to the ground terminal (low line of the Aux winding). Is it of any use? if so, should it be full round, touching either end? will it not make shorted single turn? Also I have seen a full round copper strip (ends soldered) after the assembly of the E-E cores, parallel to the winding, and connected to the same ground point? will you please explain the significance of these ?

[@supersilve]

The first case of a safety screen is generally used for safety. This is normally placed between primary and secondary windings so that if there is a short the primary winding will never come in contact with the secondary winding. This safety screen is not a complete turn and the ends must never come in contact with each other. As you said this is usually connected to the ground side of the high voltage. The other case of putting a copper screen around the outside of the core the ends are indeed soldered and this is to prevent EMI from the transformer core. This is not connected to anything.

[@saicusko]

Настоящая хорошая работа! А не рекламное шоу...

[@supersilve]

Thank you

[@vivekkumarthakur7190]

I want to ask why primary turns is wind half half please elaborate reason behind that. If I want to wind the primary at once can I do tha ??

[@supersilve]

The reason for winding the secondary between two half primaries is to get better coupling between the windings. However you can still wind primary then secondary.

[@vivekkumarthakur7190]

@@supersilve Thankyou somuch for your response brother. I want to ask 1 think more if I first wind primary and then secondary will there be any change in output voltage and current ?? If yes will it be negligible or (more or less than 1volt) in relative to the winding of (1st Half Primary then Secondary and 2nd half primary) ?

[@advertiva]

Learn a lot, thank you very much

[@glenndoringuez9560]

Does SMPS transformer needed an insulating Varnish?

[@supersilve]

Yes it will be better to immerse in varnish when ready. It helps insulation and also prevent windings from vibrating during operation.

[@anuwattanaiatkhlik1306]

Thank you very much

[@ioduremetallique]

if i would be you, i would place margin tape for all windings, this is more safe for creepage distance and better for the magnetic coupling; (reduction of leakage inductance) > important for minimize loss in flyback topology for example;

[@supersilve]

Thanks for the advice

[@ottodeacon303]

instablaster.

[@alialpha8982]

good job friend i learned a lot of things by watching your technic but what about shielding ?

[@chbonnici]

silvio please can you tell us how to calculate the power of the transformer core.

[@audiokees4045]

You can use ExcellentIT google it.

[@joelmathews3934]

Is it litz wire

[@seshansesha7645]

Thanks a lot professor....

[@sayyidsahal4533]

Lot of information 👍👍👍👍

[@ruption9865]

smartest winding machine ever

[@supersilve]

Really simple when you know how, well it suits my needs and does the job just the same.

[@SevenDeMagnus]

Hi. When do you know if a power supply needs to be rewinded or some other components like the capacitor or resistor or transistor, need to be replaced instead? I have a Famicom power supply, it's a video game console. When I measure it at the end of the power supply jack (where it plugs to the unit), the measurement is less than 0.5v only. The specifications of the power supply is: MODEL HVC-002 MITSUOKA D.S AC100V 50/60Hz 18VA DC10V 850mA Our mains/outlet is 220v (s.e. asia). It'd be nice to restore it to its original. I've already opened it (it's got the rarest screw I've seen, tough to unscrew) it. When I test the voltage (using a step down transformer), what comes out of the jack (the end you plug into the Famicom) is less than 0.5v Thank you. God bless, Proverbs 31

[@supersilve]

I guess your supply is a flyback type. what you should look for if there is nothing evident is for a high value start up resistor usually 1mega ohm or so which is open circuit. Change it. Look also for bloated capacitors, these may be the cause also.

[@SevenDeMagnus]

Thanks. Describing the insides: There's no fuse, there's a small board w/ 16v 2200uF capacitor, then 2 larger than normal resistors (if they are resistors), it's black, each with two silver or white bands at one end. They have the label M2. The there's the big metal with coils of copper in it where this board is connected (3 connectors). The two prongs are also connected to this heavy square metal with coilings in it. Is the next step to desolder the capacitor and the resistors (if that's what the black small cylinder are- it's laying flat on the board). How do I test if the capacitor or black things are broken? By the way, what's the symptom that an adapter needs to be rewound? I hope this one doesn't need that and it's just the capacitor or resistor. Thank you. God bless, Proverbs 31

[@SevenDeMagnus]

By the way. I'm replacing a ceiling fan's capacitor. The problem is the capacitor has two red wires. How would I know which is the negative or the positive. I'm replacing it with two 3uF 250VAC, connected in series. Thank you, in advance.

[@jonasribeiro3479]

What is the number of first and second AWG wires, EE65 Inverse from 12v to 220v? Thank you

[@supersilve]

For the first winding Primary for 12-0-12 it is best to use copper sheet 0.2mm thick insulated with Mylar tape. You will be needing around 4 to 6 turns depending on the core material. For the secondary 220v well I think 0.8 to 1mm will be ok

[@suhailasaba1051]

Is there an explanation regarding for why as increasing frequency would give more power for a switching mode power supply ?

[@supersilve]

With a higher frequency the flux density in the core will be higher. The higher the flux density the higher the power. So for the same core if operated at 20KHz will give a certain amount of power and say for 100Khz the same core will give nearly double the power. At higher frequencies the losses are also greater so do not take it for granted because there are special core materials to work at higher frequencies more than 100kHz.

[@suhailasaba1051]

@@supersilve Thank you for your answer. Is there a formula that shows the relationship between the flux density and the frequency? Is there a formula that shows the relationship between flux density and power ?

[@supersilve]

@@suhailasaba1051 There is software available than can work out the power of a particular core so that one can avoid the complicated mathematics involved. The size of the core, the core material and frequency used will all depend on the power for a given core. This subject is quite vast but if you are interested you can follow Robert Bolanos and also professor Sam Ben Yaacov videos on youtube.

[@suhailasaba1051]

@@supersilve Thank you for your answer. Thank you for your time Silvio. Thanks for your good video.

[@wilberallccahuamanyarasca3978]

Good video teacher, could you tell me where I get the diagram and the pcb to download it. Please, if you give it to me, I will thank you forever. See you soon, God, sell it.

[@TheWeftmen]

Sir, I have ERL 35-2 for atx computer psu power transformer, I want to rewind but I can't, in this transformer 4 primer pin and 7 seconder pin, how can I start rewind? And I want to know atx smps topology but I don't know, it is 'Powerman 350 watt' can you control on internet this atx smps then say me what is the topology, in my psu hot side only one power mosfet and one big power transformer other small transformer..

[@supersilve]

It all depends on were are your traces on the pcb to decide where to start and finish your windings. For your second question regarding having only one mosfet the topology of that smps is most likely a flyback. The small transformer is probably the 5 and 12v standby smps.

[@TheWeftmen]

@@supersilve okay thank you, can I ask again something on my mind later

[@wargaming67]

Hi! I have seen your vid about your 1000W SMPS and have already seen your schematics on diysmps, and I would like to ask, if you can recommend any books, online courses or any resources on the design of SMPSs? Not neccessary to be a "for beginners" material. I plan to build a 450W +50V, 0V, -50V (maybe smaller other voltages also for EQ) SMPS for a 100W RMS/120W (peak) stereo audio amplifier.

[@supersilve]

You can look for SMPS cookbook from Marty Brown. You may find circuits available on line but the very good ones are not easily published by everybody. Not everyone will like to share his hard work.

[@wargaming67]

+Silvio De Leonardo Thank you for the reply, I will check that out!

[@joshnabours9102]

It is low key genius to use odometer parts to count your desired number of windings down to 0.

[@aesvlog8056]

yan din gusto ko mashare sa mga gustong magaral

[@supersilve]

Yes you can share it if you want.

[@mojtabahoseini8975]

20:53 Dude the camera is focused on your junk 😂😂

[@electronic7979]

Excellent

[@davey2k12]

why not twist all of the coils second winding looks like a nightmare lol ....very good video ..good work

[@supersilve]

Well it is true about the second winding. It was not actually planned like that at first but 2 twisted bundles. I would have glued the wires before hand side by side prior to winding if it was planned to do them that way.

[@BritishEngineer]

1:10 what dk yeh orange capacitors do?

[@supersilve]

They divide the rail voltage to create a centre ground.

[@minazulkhan8287]

Great

[@shahidayaz9090]

Sir what is the important of slive

[@supersilve]

The sleeve is important to ensure good insulation between windings.

[@leonardorommelescalantequi8027]

I got a question but before "excelente video" my question is why in the secondary 6 wires

[@supersilve]

The amount of wires used is according to the current handling in the secondary this being in the region of 6 to 9 amps.

[@leonardorommelescalantequi8027]

Silvio De Leonardo thanl you i got it, i am a beginner in this topic and your video is very useful, i have a lot of question yet like i have to wind in that way for every topology for example half bridge i mean first half primary then secondari and then other half primaryand if it s posiible only use that yellow tape i forgot its name i don t have the other one

[@supersilve]

If you are a beginner I suggest you work with low voltages first as Mains voltage is lethal and can kill you. SMPS is no joke when they blow. Transformer winding for Mains voltage has to be done with care as I showed in the video. If ever there is a leak between the primary and secondary mains potential will be present on the low voltage and you will get electrocuted. It is advisable that you have an isolation transformer so that you will not be playing with mains directly.

[@supersilve]

The way to wind transformer for tight coupling, yes the way I showed is a good practice to sandwich the secondary inside the primary winding, It will not always be possible to fit the winding in one layer and considerations will have to be made before hand in what type of thickness of wire, frequency used, the size of the core you have etc. There are other methods where loose coupling will be needed such as resonant smps. These in turn do not need tight coupling but that is a different story. Make some reserch on the net and you will know better.

[@leonardorommelescalantequi8027]

thank you mr.silvio by the way i m from Peru go on your videos are great

[@lovely2561]

Dear can you full explan and circuit daigram 12v 2amps

[@devdevan551]

Sir ,can you give details of tranformer 52-0-52,16 amp with 12-0-12 1 amp?? Please

[@supersilve]

You will need a bigger transformer and more powerful transistors. You are talking of an smps of more than 1600w, which needs a whole new design.

[@repairing1118]

Thanks I did nt know what are you doing after 47:10 minutes but anyway itis useful thanks

[@supersilve]

Maybe you where staring and thinking of something else lol

[@feryboomerssidabutar8468]

👍

[@doriantech9064]

What about EMI? What about parasitic capacitances? What about skin effect?

[@supersilve]

The subjects you mentioned are beyond this video and it requires another video to explain these topics. However there are a lot of material on the internet that explain them.

[@SevenDeMagnus]

New subscriber here.

[@rahulkumar-qu2xo]

why you are using 6 wires during secondary wind-please explain

[@supersilve]

The 6 wires are there so that it can handle more current than a single wire

[@rahulkumar-qu2xo]

thank you -so basically is there any handy rule to understand how many wire used-as in primary you used 3 wires-sir i am not able to open any pic in your website after log in-please give permission for access-username-rahulrahulll

[@supersilve]

The website is not mine but you have to register with user name and password. Then you can see and download all. The number of wires used in primary are 4 twisted and in secondary are six side by side. The number of wires is calculated from the cross sectional area of each wire. The amperage is calculated as 6 amps per mm squared. That is why I used 4 and 6 wires depending of the current drawn by the smps in the primary and secondary respectively.

[@rahulkumar-qu2xo]

thank you-can you please request website to allow--i have registered and done verification with activation code but still not able to see pics-error seen-for past 3 days--Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system? If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.

[@DolezalPetr]

very good

[@nicolabarlaba3298]

Ciao! Complimenti per il video. Non ho ben capito perché lasci quei 4 mm di spazio alla fine degli avvolgimenti. Ti dispiace spiegarmelo? Grazie

[@supersilve]

You can use the subtitles on youtube and use the auto translate in Italiano. You will understand better that way.

[@nicolabarlaba3298]

Hi Silvio, please forgive me i tought you spoke italian because of your italian name. I actually understood what that margin is, but i can't understand the reason of this. You say that it has to be done because we don't want windings leak out each other, so i would like to know if there is only this mechanical reason or there is a coupling reason too. Thank you so much

[@supersilve]

Ok I will make a brief explanation. The side margin for windings in these type of transformers is mandatory for safety. The path distance must not be less 4mm. This could be divided in two thus having 2mm on each side of the winding this includes all the windings. On the other hand it could be on the winding that is carrying the mains supply but has to be 4mm and there is no need to leave margins on the secondaries. If you need more information you can visit diysmps.com and find my blog post called Transformer winding practices for smps. You can download the pdf file attached with this blog post. I hope this helps you understand better.

[@nicolabarlaba3298]

Thank you for your answer Silvio. I've just seen your blog, downloaded the pdf and read it. It is pretty clear about my question and seems that the reason of that clearance is the isolation between windings. Now i'm an electrical engineer, but as i'm 24 i have not a lot of practical experience about this. Do you think that isolation may be a such big problem in this SMPS with output voltage within 100-400 Vdc ? Have you ever seen any arc during normal operation of these transformer without margin clearance? Do you think that the lack of that space will ever cause arc or its just precaution and such "good way to do that"? Thank you very much

[@supersilve]

No I did not encounter any sparks yet, we must not forget that square waves tend to have a lot of DC content in them. DC tend to spark more readily than AC. See ratings on relays and that is a good example. The environment the smps is working also plays an important factor and at times they get very dirty due to fans pulling in dust, moisture also plays its part in this regard. Above everything else this is something mandatory with the EU specs . I had to give a good example in my video at least its best to learn the good way. I cannot be responsible for anyone who gets electrocuted due to a bad example.

[@coloradowilderness3139]

Nice .

[@ammaralyasiri4191]

can you provide the book about smps transformer and thank you very much

[@supersilve]

Sorry no I make my research on line

[@anant814]

hi silivio,how to make this machine?

[@supersilve]

which machine are you referring to?

[@anant814]

how to make my own winding machine setup similar to your winding machine so that I can also build my own inductors and high frequency transformers at home.

[@supersilve]

The machine is very simple as you can see. I use a treaded rod of 8mm with some nuts and washers. the base frame can be made of wood if you want. The handle for turning the treaded rod well you can leave the rod longer and make the handle with the same rod by twisting it to shape. for the counter well I used an odometer from an old truck and fitted it to the wining machine. You have to use your head to make things and I cannot explain all the detail here. You can take a look at it and it is very simple to make.

[@anant814]

ok thanks silvio

[@Rayan-oi3od]

Winding EC42 transforme. please Mr

[@crazzzymick1]

You used the word leakage to explain the need for a margin is that mechanical, electrical or magnetic leakage

[@supersilve]

The word leakage will explain both electrical leakage regarding the margin clearance . Magnetic leakage inductance however in the case of the type of smps I am building is kept to a minimum by keeping the coils tightly wound together with minimum clearance as possible.

[@bijinapallitrinadh3002]

Can I know schematic

[@PawanKumar-sk8tj]

Sir, increase my skill by you

[@supersilve]

Very good that is why I posted the video

[@putrasepuh3487]

PDf sir🙏🙏🙏

[@truongxuan9508]

share file smps

[@sksksamim5588]

sk