Building a transformer

In message , dated Tue, 8 Aug

2006, ian field writes

That depends on how the leakage inductance is produced, and whether you can remove it, which you must in order to use it as a conventional transformer

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2006 is YMMVI- Your mileage may vary immensely.

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

I said it was silicon. The Ge device I used in HS was a Delco doorknob power device. I did 10W class-A ;-)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

They were, and were already pretty cheap. I used them at work in a big current regulator in '74 or '75.

John Perry

So......

Fuck man! Switch that shit!

Nope, nothing else I can say without profanity.

SMPS, use a range of supplies, or just go SOL.

I mean, are you really planning on water cooling the maximum 600W you'll dissipate? Heatsinks that size can get pricey. Don't say it won't happen (the full dissipation).

Tim

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Deep Fryer: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

I was only taking issue with your tense -- the 2N3055, while venerable, appears to be in current production. So it's an 'is' part, not a 'was' part.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Posting from Google?  See http://cfaj.freeshell.org/google/

"Applied Control Theory for Embedded Systems" came out in April.
See details at http://www.wescottdesign.com/actfes/actfes.html

Put a search in Ebay and store that page. Keep looking - odd and large transformers come up often, and go for quite reasonable prices. But what you want (roughly) is common on large audio power amps, so shouldn't be difficult to find.

Because of economies of scale buying the materials needed to make one will cost you much more than a factory - and that's without the time and difficulty involved.

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    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

Yup - Quad were using them in the 'late '60s in the 303.

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    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

What pray-tell is an RMS Watt? " Put out 400W RMS into 4 x 16 ohm speakers in parallel."

Sine wave into equivalent of 4 ohm load... 4 each 16 ohm speakers in parallel... I think... it was 30 years ago, might have been 4 each 8 ohm speakers... 2 ohm equivalent load. All I remember is the 400W ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Do you need both + and - power at the same time? If not, just have 0-50V would save you half the power. If you need to use 1V at 5A, your power supply would become pretty inefficient (supplying 5W and wasting > 300W). Are you planning to fan cool it? If not you need a huge heat sink.

If you use a switching design, it would be a lot more efficient.

A watt is a watt - a measure of power. So can't be qualified by RMS or whatever. Although that doesn't stop the advertising boyos trying...

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    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

I was just trying to distinguish the number from those that the "music power" types like to bandy around.

For instance peak instantaneous power would be 800W ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Get a copy of the 1980 book: Practical Transformer Design Handbook Eric Lowdon Howard W. Sams & Co. book publisher ISBN: 0-672-21657-4

I would need the option of both +v and -v in respect to ground, but only sometimes at the same time (ie when testing audio circuits, but not when doing logic circuits) if I switched one of the secondary windings off... would I still be saving half the power?

Wastage is becoming more apparent as I read more and more posts... and am considering rethinking to a more energy efficient design now.

I was (originally) thinking big heatsink with some thermal controlled fans screwed on.

switching psus I know nothing about, but think I will research this. Any good places to start (apart from the obvious google)?

Does nobody knows howto calculate transformers anymore?

this will be a 600Watt transformer

you will need iron of 150mm EEE and III (a standard dimension) a form of 50x54mm

primary: use 1.35mm diameter wire roll 377 spirals

secondary: use wire of 1.77mm diameter (if this does not exist, get the after next in diameter) weld first out line (60v) roll 104 spirals weld second out line (0v) roll 104 spirals weld third out line (60v)

put the irons one by one always alternate positions tight as much as you can the irons dive it into hot varnish and let it dry

this is just the transformer, i guess you will also want to pass AC to DC and maybe a voltage regulator controlled by a variable resistor, but that is another story ;)

regards ArameFarpado

2N3055s are as common as 2N2222s. Salvage them from junked supplies or amps, and the cost is nothing.

Yea I know. That's very common in the audio industry but we Engineers should know better and use the proper terms. America is stupid enough without us adding to it, don't ya think?

I've run out of library shelf space, so I've been donating out of date books (like "Mother of All Windows" for Win95) to charity book sales ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

It's in my GE handbook from 1973. ISTR some magazine article from 1971 using it, but I'm not going up in the attic dusting off that pile of old mags.

- YD.

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