I would not consider 11 kg to be close to a 2kVA CCS transformer. The
AL-1200/1500/82 Dahl is 15 kg and that is ICAS (2570V/800ma) and a C Core
yet it still has to be derated for RTTY, etc.
A stock SB-220 transformer is close to 11 kg and its rated at 600VA.
Also remember those ratings are DC input power, not RF out. Add 15-20% to
the weight for E-I construction.
Carl
KM1H
----- Original Message -----
From: "Jim Garland" <4cx250b@miamioh.edu>
To: "'Ulf (SM0NOR)'" <ulf@sm0nor.com>; <amps@contesting.com>
Sent: Monday, March 04, 2013 7:55 AM
Subject: Re: [Amps] Transformer choice
Hi Ulf,
To me the choice depends on how much you trust Company B. If Company B can
be trusted to meet their quoted specifications (2000VA with 2.5% voltage
drop at full load), then I'd go with them. As you note, 11 kilo is as big
or bigger than the transformers in many ham-rated commercial amps of the
same power rating. If you're planning on heavy contest use, or RTTY
service, then Company A is probably the better choice, but for routine ham
operation I'd think Company B makes mores sense, considering the large
price differential. An interesting choice.
73,
Jim W8ZR
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Ulf (SM0NOR)
Sent: Monday, March 04, 2013 4:29 AM
To: amps@contesting.com
Subject: [Amps] Transformer choice
Hi Guys,
I'm looking for some feedback on two transformer offers I have. I'm
intending to build a
table top amp, so I'm accepting some compromises regarding the
transformer. I have made
inquiries to a couple of winders and I have boiled them down to 2 offers.
I was asking for
2000 Volts @1A =2000VA (+ G1 and G2 windings). I'm targeting to get
2200-2400 watts
output in PEP service and about 1K in continuos service.
Both companies claim 2000VA but at different core weights
Company A:
17 Kilo toroid, D=200 mm, H=110. About 3% voltage drop at full load. Max
temp rise =
105C over 40C ambient. DC resistance, about 25 ohms.
Price: €480
Company B:
11 kilo toroid, D=180 mm, H=85mm. About 2,5% voltage drop at full load.
Can't, or don't
want to specify other data.
Price: €195
So what are your reflections? The A is obviously a the better choice.
They are serious and
they offer detailed specs, exact delivery times etc. But all comes at a
premium price.
Company B is smaller and they obviously compromises with their
specifications, but the
price is a lot lower and so is the weight.
Now, I don't expect the cheaper and smaller core to do wonders. The
bigger one will for
sure be more rugged and closer to "true 2000VA", especially if I run it
in true continuous
mode. I'm inclined to go for the the bigger one, because I want the best.
But OTOH, I don't
want to waste money because of a "feeling". Perhaps the smaller one will
be enough given
the table-top size/PEP service I'm targeting? After all, it matches
what's inside most
commercial amps in this category.
I'm happy for any feedback...
73's
Ulf (SM0NOR)
ulf@sm0nor.com
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