Phil Allison wrote:
"Patrick Turner" = asinine, criminal ****wit
The people at Tortech ( aust ),
http://www.tortech.com.au/toranalysis.html
say this
** Tortech is a small transformer winding business in Sydney. They buy lams
and wound cores from local and foreign suppliers. The owner is Mike
arkin - he supplied me with the 160VA wound core I use in my test. It is
the same as ones he uses to make AC power transformers.
I know Mike Larkin.
In 1995, he quoted me a huge figure for a PT, choke, and two OPTs.
He said he was unable to do the OPTs in Oz because the finest wire he could use
was 0.63 mm dia,
and that he'd have to subcontract the OPTs to a company called NZ Coils P/L,
which
I have never been able to track down.
I thanked him, and said I'd consider the deal for awhile.
Since the material costs were about 20% of the huge quote,
I figured i'd be better off winding all this stuff myself, because my hourly
rates
are far lower than his.
It is impossible for any Oz transformer winder to make me anything
at a price where I could then use in amps which I could then sell
to compete with chinese imports and make a wage.
Mike would understand this.
It is most likely you have good GOSS material in the test core you used in your
test.
Its not hard to find out just what you got.
Just measure the inductance at 50 Hz across a range of voltages until saturation
occurs, and note the maximum L.
Then work out what the Bmax is for where L is at a maximum.
Probably you may find L max is where B = about 0.8T.
Knowing what turns, Afe, and ML you got, you can work out what the U must be.
My point I made previously was that since there is such a **HUGE** variation in
the U and losses
in E&I lams and Ccores I have purchased, it follows thet not all of what is
claimed to be
GOSS is identical.
And I maintain that just because some GOSS is wound into a spiral,
the U compared to an interleaved E&I tranny won't necessarily be
10 to 15 times what it is in the E&I lams.
And I would maintain that if you had some "plain old transformer iron, ie,
not GOSS, and you wound some into a toroid, there would be a considerable
increase in the U compared to E&I, but just how much I don't know.
The para quoted below does not even contain the word "toroidal " so has no
relevance to the heading - as is usual for the Turneroid autistic .
But it was from Tortech, who praise the virtues of their toroidal wares...
These pages all give the steel strip material used by toroidal mains
transformer makers as being GOSS.
http://www.airlinktransformers.com/t...al_toroid.html
http://www.tabtronics.com/toroids.htm#core
http://www.isomatic.co.uk/toroidalcores.htm
http://avellindberg.com/transformers...ech_notes2.htm
................ Phil
Thankyou for the references.
From one they say
"Since toroidal cores are constructed of a continuously wound ribbon, there is
virtually no air gap. The windings are evenly
wrapped over the entire core allowing the transformer to operate at a higher
flux density than in standard transformers. Toroidal
transformers can operate at 1.6 to 1.8 Tesla (16,000 to 18,000 Gauss) while EI
cores are limited to 1.2 to 1.4 Tesla (12,000
to 14,000 Gauss)."
I have never seen a toroidal tranny set up to run at 1.8T
***ALL*** the several toroidals from Jaycar were set up to run at no more than
1.25T, and all were disgustingly noisy and unacceptable in hi-fi amps.
Two 800 VA toroidal transformers made by Harbuch were also unacceptably noisy,
and
also set up to run at 1.25T, and the only way I could shut the buggers up
was to remove the secondaries by winding the wire onto a notched
dowel shuttle by hand, and add 33% more turns to the primary, and then rewind
the
primary, all with a shuttle.
It took days.
But I got there, and the trannies finished up acceptably quiet for
use in tube amps with a main power going to a rectified plate plate supply,
despite the fact that the re-wound tranies were not vacuum varnished, but
empployed the same insulation technique of winding tight strips
of polyester on which is then further self tightening when layers of wire
are pulled tight ove them.
One amp has been in constant use since 1996, and the tranny runs quiet.
Needless to say, the core losses are negligible, but I measured it all, since i
assume nothing.
Since getting toroidal OPTs properly wound with all the taps and multiple
windings
i wanted and with epoxy resin
impregnant vaccuum impregnated is prohibitively expensive
and unlikely to even be available, I was forced to look around
for decent low loss E&I, and I came across Sankey who make the
GOSS E&I that measures U = 17,000.
I have to buy $400 worth each time, since their minimum order is
50 Kg.
I had previously bought some british made imported GOSS E&I,
I think it went about 7,000, not too bad....
Plitron wind some splendid toroidal transformers.
They do cost quite a bit though.
Patrick Turner.