Joe,
I still can't see $2500.00 for that. Take into consideration the large
C-core plate transformers by Dahl. They all run $350.00 each and are
heavy suckers. It would take seven of these to equal that. Now smaller
transformers I won't be much into, under say 100 watts so I couldn't
quote those by guessing. But, a plate transformer, B+ choke,
screen-bias-heater-control transformer (813 is a tetrode), using Dahls
prices at the $350.00 mark, is only $1050.00. Of course the cost of the
choke and the screen-bias would be cheaper. My cost for just those three
is about $475.00-$500.00 or so. The audio transformer shouldn't be no
more than the cost of the plate transformer. So that would get us about
$725.00-$750.00 for the four. Don't hold me to that as I didn't actually
calculate the sizes I'd use so the cost could be more or less.
Whoever quoted you $300.00 for that modulation transformer was robbing
you! It doesn't take that long to design a two winding transformer. That
transformer isn't that big. Matter of fact, you could re-wind that
yourself easily. Just set down one night where you wont be disturbed and
slowly count the turns on each coil. Just write down on a piece of paper
every 10 turns or so. One or two turns off doesn't matter a hill of
beans. Fortunately, I built this transformer winder so it will run in
any direction and the counter will count them off so it's easier for me
to re-wind one. I'm not sure if they used a paper bobbin back then or
not. Some used plastic going way back. Plastic bobbins are generally
jumble wound and do not have any layered insulation. These types have
one coil next to the other instead of one over the other. If it's paper
layered, it easier. Count the first layer, then count the second. The
second will have a full winding to the margins. Then, simply multiply
this by the number of layers left for that winding, and add the number
on the first one. These go really quick. After your done, gage the wire
for size. Use that size for the same type to rewind with. If you can't
find paper, brown paper bags will do if they're the heavy ones. You need
a minimum of .005" thick but preferably .007" per layer. The varnish can
be air-dry polyurethane and will work just fine. Just let it set for 48
hours before you use it. One word of caution about the wire. You need to
determine the wire length you'll need. You take the middle section of
each winding and find its' circumference. Multiply the circumference by
the number of turns. If you run out of wire while winding, it's a bad
idea to try and splice it. If I can help you, just holler.
Will Matney
Joe Isabella wrote:
Keep in mind that a project like that will require multiple XFMRs. HV, Fils,
possibly a choke
input, screen (do these need screen V?? Can't remember...), modulation XFMR,
and various other
interstage XFMRs. So $2,500 worth of iron isn't unbelievable, especially from
Dahl. I was quoted
almost $300 for a Johnson VikingII mod XFMR (not even from Dahl!), and that's
only a 100W AM
rig...
Joe, N3JI
--- craxd <craxd1@ezwv.com> wrote:
Manuel,
It's very easy for me to compete using EI cored transformers, the C-core
is another case. C-cores are expensive to buy one at a time. The only
way you can come out is buy about three of the same size at a time.
That's the reason Ameritron has that price due to ordering maybe 20-50
transformers at a time. One C core rated for about 1 KVA might run
$140.00 each, but buying three might drop them to $60.00 each. This was
what the Magnetic Metals rep told me about two weeks ago. The steel in
these C-cores is Microsil which is the same as Hypersil. Either is just
a CRGO silicon steel with 3.5% silicon.
On quantity orders for EI transformers, you can drop the price due to
running the windings all at one time. Sometimes you can wind two or more
coils at once on the same lathe. The steel gets cheaper on larger orders
too. By agreement, my steel and copper prices are about the same that
Dahl pays.
My major problem is being handicapped and handling heavy transformers. I
can handle up to about a 3000 watt by myself. I'll be able to do larger
as a custom, but won't unless I have to. Another thing is it takes me
slightly longer to build one up than what it would if I was up and about
so the labor goes up. The more I get into this, the costs will drop some
by coming up with easier ways of doing things here.
The one that you mentioned costing $2500.00, what was the requirements,
voltage and amperage? I can tell you pretty quick a rough quote for
using EI cores. A C-core, I have to get quoted. What you wanted don't
sound to me like a lot of transformer.
Best & 73's
Will Matney
Manuel R. Alonso / KC4MNE wrote:
Hello,
I am excited to have a new player in the Ham transformer market. Can't wait
to see your pricing on plate transformers, and maybe even some plate
Modulation and audio iron. But pricing is an issue. I see you comparing a
lot to Dahl, well You can buy a Dahl made transformer that Ameritron uses in
the 3cx1200, 3cx1500, and dual 3-500z amps from Ameritron for about $250.00.
(2560 V .8 A CCS)The price to purchase directly from Dahl is MUCH higher.
Hopefully we can get equal pricing one the 1 pc orders from you, that Dahl
only gives to the volume customers like AMERITRON, QRO, ALPHA, ETC. It would
be nice.
Had Dahl quote me on iron once for an am transmitter, think it was for a
pair of 813's modulating a pair of 813's. His iron quote was like $2,500 for
all the pieces, That was the end of that project!!
Sincerely,
KC4MNE
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
Behalf Of craxd
Sent: Tuesday, October 05, 2004 11:49 PM
To: gdaught6@stanford.edu; amps@contesting.com
Subject: Re: [Amps] Transformer shop update
George,
I was actually going to make them heavier than that. The screen windings
were going to be rated at 250 mA, the bias at 125 mA, the 12 V at 2
amperes, and the 6 V winding at 10 amperes. Most all the supplies will
have losses and actually require more current than the DC output. These
will be able to run full wave, half wave, and doubler circuits with room
to spare, running at CCS. I wanted to do this to keep the heat way down
to where they could be mounted in chassis that wasn't ventilated well. I
figured a rough price of $100.64 each with a watt rating of 205 watts to
compare to Dahls pricing of similar. These use an EI 1-5/8" laminate
1-1/2" in depth. The physical size of the core is 5-1/4" wide x 4-3/8"
high x 1-1/2" deep, with the steel weighing 8 pounds. The estimated
finished weight will be about 12 pounds. You can look up a similar
transformer at Dahls website weighing 12 pounds and 205 watts. Thanks
for the interest, I should be up and running around December.
Best & 73's
Will Matney
gdaught6@stanford.edu wrote:
Hi Will,
By December, we should be winding as scheduled. I will first be
offering some screen/bias transformers with heater and control
windings included. The screen will have taps for 315 Vac, 275 Vac, and
236 vac. That will give 445 Vdc, 389 Vdc, and 334 Vdc.
At how many mA? 100mA would be good.
They will have
a 90 Vac bias winding, 12 vac control winding, and 6 Vac heater
winding.
One Ampere on the 12v winding; and how many on the heater winding?
Heater for what?
If the price is right, I'd like one (or even two!)
I hope there's enough of a market to make it worth your while! Good
luck, and keep us posted on the Amps reflector.
73,
George T. Daughters, K6GT
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