[Amps] Transformer choice

[Hsu]

I just order a 2kVA toroid , OD=200mm, H=130mm
weight over 20kg, Price=$180

-----原始邮件----- 
From: Carl
Sent: Tuesday, March 05, 2013 4:57 AM
To: Jim Garland ; 'Ulf (SM0NOR)' ; amps at contesting.com
Subject: Re: [Amps] Transformer choice

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 at miamioh.edu>
To: "'Ulf (SM0NOR)'" <ulf at sm0nor.com>; <amps at 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 at contesting.com] On Behalf Of Ulf (SM0NOR)
>> Sent: Monday, March 04, 2013 4:29 AM
>> To: amps at 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 at sm0nor.com
>>
>>
>>
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>
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