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From: John Woodgate
Subject: Re: 2.5kW-3kW-SMPS-(cheap)-suggestions?
Date: Tue, 17 Dec 2002 13:00:25 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Tue, 17 Dec 2002 13:56:13 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that John Jardine
wrote (in ) about '2.5kW-3kW-SMPS-(cheap)-suggestions?', on Tue, 17 Dec 2002:
>110-50 transformer?. No thanks!. Extremely efficient but too heavy, too
>expensive (toroidal or otherwise). Fixed voltage ratio gives consequent
>problems with power factors at other than nominal i/p.
>I'll willingly put up with heavy heat-sinks and more waste heat.
Gibbo obviously forgot that you posted originally:
The suggestion is for a piece of portable kit that will be powered from
an on-site 110Vac generator (95V-140V building site type!) and will give
as o/p (unsorted yet) 40-50V DC (say 55amps max). The power will be
dumped into a resistive heating element (one shot) for up to maybe 30
minutes a time. Operating duty cycle about 60%. ('tool' rating).
The kit needs eventually engineering to a best cost, as it would be
compared to existing equipment using mains transformers
The SMPS design is FAR from simple, especially with the wide input
voltage range and the need for intensive PFC. The obvious question is
'why are the heaters designed for 40 to 50 V?' You have no electrical
problems, no weight, no cost, if you only can get 110 V heaters.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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