| schematic for a + -30v ,300va smps - Click HERE for Original Thread |
| sagarverma |
| does anyone have schematic for a + -30v ,300va smps:D |
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| sagarverma |
i have already made that one .its working great in my car:)
i want a mains smps schematic, + -30v,300va i.e input is 220v ac,o/p is + -30v for power amp.googled but zilch.:bawling: |
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| Eva |
| I'm just curious: Why do you need conventional 50Hz transformers when you have built SMPS that can be extended to provide these outputs? |
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| richie00boy |
Basically you run the control circuitry off e.g. a 12V little transformer, then rectify the mains to give you a DC rail to connect your SMPS transformer primary to. Adjust SMPS transformer pri:sec ratio to suit.
I believe further discussion on these forums is prohibited due to the lethal voltages involved. If you can't make instant sense of the above scheme then DO NOT ATTEMPT IT YOU WILL LIKELY DIE DUE TO VERY HIGH DC VOLTAGES |
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| pinkmouse |
Thanks Richie! :)
:cop:
Sagarverma, please don't hijack threads. I'm splitting this off on it's own. |
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| sagarverma |
| quote: | Originally posted by richie00boy
Basically you run the control circuitry off e.g. a 12V little transformer, then rectify the mains to give you a DC rail to connect your SMPS transformer primary to. Adjust SMPS transformer pri:sec ratio to suit.
I believe further discussion on these forums is prohibited due to the lethal voltages involved. If you can't make instant sense of the above scheme then DO NOT ATTEMPT IT YOU WILL LIKELY DIE DUE TO VERY HIGH DC VOLTAGES |
this is exactly what i had in mind(but not the dying thing,i use adequate safety[more safety] after a heart breaking accident).
will it work?have u tried it(in any design of smps)?
PFC circuit will also be required for mains,how to include it?
| quote: | | Sagarverma, please don't hijack threads. I'm splitting this off on it's own. |
hey,cops r here:D
Sagar |
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| richie00boy |
Of course it works, that's how it's done commercially :) PFC is not required for such a small VA.
IMO for such a small VA I would just use a conventional linear supply, much safer and easier to get working and probably no bigger/heavier. |
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| pinkmouse |
| quote: | Originally posted by sagarverma
hey,cops r here:D |
Have you never seen the movie, Minority Report? ;) |
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| sagarverma |
| quote: | Originally posted by richie00boy
Of course it works, that's how it's done commercially :) PFC is not required for such a small VA.
IMO for such a small VA I would just use a conventional linear supply, much safer and easier to get working and probably no bigger/heavier. |
is it?i opened up an smps(12v,1amp),it was a telephone charger and had small transformers,tl494,and fast bridge.transformer didnt looked like standard 12-0-12.
cost savings will be great for smps.in my case,almost halved.+weight issues,linear power supply has ugly bulky xformer,very heavy +space savings.
can u suggest suitable core dimensions(torroid),will the same core as of car smps do?any special components that can be included?
any precautios or suggestions?
| quote: | Originally posted by pinkmouse
Have you never seen the movie, Minority Report? ;) |
TOMMy,cops forsee,arrive b4 murder:o
pinkmouse,r u planin same system here:D.moderators forsee postjacking,they come in n say"hey!u can't post today". |
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| richie00boy |
It may not be 'standard' 12-0-12 transformer, but remember it's not an audio device ;)
The same core for your existing SMPS will be fine as it's the VA rating that counts, voltage is not a factor.
I was trying to say that for just 300VA, by the time you have added the control transformer and it's recitifying parts, the control circuitry, the mains rectifiying parts and the transformer, the whole thing won't be much smaller than a linear supply, as it's harder for the DIYer to make it so small. You also need to be well aware of creepage and clearance distances for the mains parts.
I say again that I would strongly advise you to keep to a simple and safer linear power supply. Do you realise that you will have near 400V DC present and DC is totally lethal at high voltage -- worse than AC. |
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| sagarverma |
| quote: | | I say again that I would strongly advise you to keep to a simple and safer linear power supply. Do you realise that you will have near 400V DC present and DC is totally lethal at high voltage -- worse than AC. |
u r scaring me.and really i m scared.400v,which part?i suppose car smps also has high dc?it went safely and is still runnin safely.
what is control transformer?
worse than ac,,,,no bec avg value of ac will b high. |
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| ashok |
"........i suppose car smps also has high dc........"
If you don't know that after building and using a low voltage smps , you better not handle any high voltages. Someone might have to write your obituary. We sure wouldn't like that kind of a situation.:dead: |
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| richie00boy |
| I agree ashok and I will not comment further to save him from fate. sag please heed my advice to build a linear PSU. |
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| sagarverma |
| quote: | Originally posted by ashok
"........i suppose car smps also has high dc........"
If you don't know that after building and using a low voltage smps , you better not handle any high voltages. Someone might have to write your obituary. We sure wouldn't like that kind of a situation.:dead: |
i know bout high voltages involved.i didnt 'see' them with mm,but i tested smps,it did 900w continous n was jus warm.
| quote: | Originally posted by richie00boy
I agree ashok and I will not comment further to save him from fate. sag please heed my advice to build a linear PSU. |
ok richie,got it.thanks for sound advise.
linear psu,i made two,very good,but very heavy and bulky.
u guys taking me a novice(i m new to diy),,but i wouldnt have made car smps and had such wonderful amps in the car had i backed off bec of dangers involved.
i have done experiments on heavy duty dc motors,induction motors
(all part of my studies),so heavy currents and adequate safety with their handling is not new to me.moreover,the dc power supply that i used to test car smps has 100amps output capability.
i really appreciate the sincere concerns of both of u.:angel:
Sagar |
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| ashok |
Hi Sagar,
The warnings are not to deter you from making a HV power supply. It is to prevent you from doing so till you REALLY are 'ready' to do such a thing. You can interpret that anyway , but we mean ' abudance of caution ' which I don't see in any of your posts. Overconfidence is the biggest killer !
High current has nothing to do with all this. Just lethal high voltages , in this case even more lethal , dc voltages. You need only a few milliamps to kill you . Depends on how you get the shock. Being paralysed is even worse than being killed ! So do be careful .
Handling electric motors is much easier and safer than handling high voltages on a circuit board !
Do not underestimate what electricity can do to you.
Keep DIY'ing ..............very carefully !
Cheers. |
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| richie00boy |
| Just to second everything what ashok said there. Good luck with your project sag. |
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| sagarverma |
so,for mains voltage,should i start with low power?
i want an smps,i envisage a small class d amp(200 to 300w),powered by an smps power supply.Imagine the light weight and space savings of smps and class d amp.no bulky and costlier-than-components heatsinks.no heavy transformers.all in a small and smart little casing.IMAGINE!the little devil than can pump out huge power:devilr:
could u guys be kind enough to tell me the requisite safety precautions that need to be taken?any special components to be used on primary side,any protection circuits that should be included?:)
----------------------------------------------------
.1 amp is SUFFICIENT to kill. |
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| richie00boy |
NO NO NO please read what we are saying. The power is irrelevant, the issue is the lethally high DC voltage that will be present for ANY mains powered SMPS no matter how low power.
Apart from the physical safety issues there will be creepage and clearance issues which you will have never encountered before.
I appreciate your enthusiasm but this is not a project that you are ready for yet. |
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| mzzj |
A good overview on safety aspects:
http://focus.ti.com/lit/ml/slup227/slup227.pdf
Then there are safety issues during prototyping and measuring performance of prototype. First, dont even think about it without isolating transformer. Second, keep one of your hands always in pocket. Wear safety glasses. |
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| ashok |
Hi Sagar,
Don't think that the previous few posts are written in a light hearted spirit. They are accurate and dead serious.:att'n:
Working with high voltage is lethal for anyone. If you haven't done it before you need to work with somone who is expert at it and get some experience yourself before doing something on your own.
Before you know it , you will touch some part of the circuit you ' think ' is safe and get zapped. God help you if you aren't using an isolation transformer -- it's like being connected to the mains with a few components in between. Dicey.... eh ?
:hot: |
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| sagarverma |
i didnt use isolation transformer for car smps.i suppose story different here,i know theory of isolation transformer but never used it in practice
i suppose its gettin to much dangerous here.
in theory,its so easy,but from what u guys sayin,good only for seasoned diy'er.
.moreover,if its so much of pain in ***,i better drop it.
i will get the smps constructed(as i did b4).
Thank u everyone for your right suggestions.
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hey cop!please delete this thread altogether(lest i change my mind). |
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| pinkmouse |
| I'll just close it, but well done for coming to your senses. :) |
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| Eva |
| I've arrived too late since the thread has been just closed, but I wanted to say that, judging by the content of your posts, I feel that you are not serious nor rigorous enough in order to do offline SMPS experimentation in a safe way. I'm Sorry if this sounds too harsh, but I think that I'm not the only people that got that impression. |
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| sagarverma |
well thats an old story,when Sagar used to be careless.carelessly making ckts.,with zero or no safety(even the etching was done barehands,fingers in acid).wires were strewn all over my 'lab',hotch-potch everything.
one bad day changed it all.due to some stray wire,one of my amp shorted,and so badly,it took the whole setup along with my costliest and dearest woofer.whole setup smoked out in seconds.
that day and this day,"east or west ,safety is the best'.
rubber(latex) gloves,mask and glasses(even when soldering to avoid fumes).proper planning,and ordered 'lab'.each thing at its place.
regarding your comments,i m open to 'constructive' criticism,not u-r-good-for-nothing variety.
if my post sounds like careless,then wait n watch,these sounds will disappear too.in practice,carelessness has been eliminated,it will surely go away from my words(if it is present there).
for its said that::
habits die hard, habit, remove h,there is still 'a''bit',, remove a, there is still 'bit'.
Sagar |
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| pinkmouse |
:cop:
OK guys, I've moved your other posts here, let's call the debate finished. |
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