You sure did mention "continuous" twice and you also asked for feedback.
Transformers should always be specified at CCS when ordering as reputable
manufacturers do not work with ICAS, IVS, or other ham versions of ratings.
What it is capable of in ham use is up to the individual.
I dont see either one of those quotes being capable of 2.5-3% regulation at
twice CCS with any sane value of filter C
Carl
KM1H
----- Original Message -----
From: "Ulf (SM0NOR)" <ulf@sm0nor.com>
To: "Carl" <km1h@jeremy.mv.com>
Cc: "Jim Garland" <4cx250b@miamioh.edu>; <amps@contesting.com>
Sent: Monday, March 04, 2013 5:13 PM
Subject: Re: [Amps] Transformer choice
No one mentioned CCS here, Carl. I was into "ham specs" already from the
beginning. This particular project calls for a certain level of mobility.
Compromise is fine..
Sent from a wireless device of an unrevealed brand.
On 4 mar 2013, at 21:57, "Carl" <km1h@jeremy.mv.com> wrote:
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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