From: Winfield Hill
Newsgroups: sci.electronics.design
Subject: Re: 12 vdc to 6vdc @ 30amps
Date: 14 Sep 2002 08:39:45 -0700
Organization: Rowland Institute
Message-ID:
References: <5f2e7e38.0209120741.1ab14efe@posting.google.com> <3e852f41.0209130356.54a5521b@posting.google.com> <4b75bb73cetonyw@ledelec.demon.co.uk>
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Tony Williams wrote...
>
> Spehro Pefhany wrote:
>> The renowned Winfield Hill wrote:
>>>
>>> What!! No heat sink!! You wimps, my circuit dissipates heat
>>> like a man's power regulator should, up to 325 watts!! Put
>>> that in your pipe and smoke it! Or put your pipe on the heat
>>> sink and it'll smoke, or ....
>
>> By cross milling channels into mating halves of the heatsink, and
>> hinging it, we could have a workable waffle maker. And the motor
>> could be used to mix the batter. It's all coming together. A
>> timer driven by a nice synchronous AC motor, some big oil-filled
>> chassis mount capacitors for one thing or the other, terminal strips
>> soldered with a 250W Weller gun. Yes! We have the technology.
>
> Wimps! ...... the pair of you. If either of you thinks that
> those pathetic attempts have any chance in this year's Brick
> Outhouse Of The Year competition, then think again. A miserable
> 12V/325W? Sit on that and it would barely give you a cheap thrill.
>
> The BOOTY is still safe by the looks of it......
Oh yeah? Look again, Mr. Tony Williams. I guess you didn't read my
reply to no-spam baggypants last week. It dissipates 12600 watts.
Winfield Hill wrote,
>
> no-spam@baggypants.com wrote...
>> cant find any quad-pentium mobo for my cars computer, so i,m
>> designing my own but the 1.8V power supply is hard- it needs up
>> to 250 amps from the engines 42V batt. i NEED a seatwarmer to
>> anybody has aome thoughts?
>
> Hi baggypants, you have two interesting problems, which I can solve with
> one circuit. You should use what we call a linear regulator, because a
> sensitive computer motherboard needs an electrically-quiet environment.
>
> +42V ____ 350A breaker
> (o)==|____|==+====+====+===+===+===+===+===+===+===+===+===+===+===+===,
> | | | | | | | | | | | | | | |
> ,--+----+ | | | | | | | | | | | | | |
> | | | | | | | | | | | | | | | | |
> | 270 | | | | | | | | | | | | | | |
> | 3W | | 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
> | | |/ | 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W
> ,---+ +--| | | | | | | | | | | | | | |
> | | | |\ | | | | | | | | | | | | | |
> 4k7 | | V |/ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
> | |/ | +--| 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W
> +-| | | |\ | | | | | | | | | | | | |
> | |\ | | V | | | | | | | | | | | | |
> | V | | | |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/
> | | | |/ +==|===|===|===|===|===|===|===|===|===|===|===|===|
> | +--|--| | |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
> | | | |\ | V V V V V V V V V V V V V
> | 1k0 | V |/ | | | | | | | | | | | | |
> | | | +--| | | | | | | | | | | | | |
> | | | | |\ | | | | | | | | | | | | |
> | '--|----+ V |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/
> | | | +==|===|===|===|===|===|===|===|===|===|===|===|===|
> | 270 | | |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\ |\
> +--, 3W 10 | V V V V V V V V V V V V V
> | | | 3W | | | | | | | | | | | | | |
> | \|_ | | 10 | | | | | | | | | | | | |
> | /_\ | | 3W 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
> | | | | | 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W 75W
> | | | | | | | | | | | | | | | | | |
> | '---+----+----+----+===+===+=+=+++++===+===+===+===+===+===+===+==='
> | 6.8V | |||
> | | ||| +1.80V, 0 to 250A
> | | '++====(O)=============,,.
> | 0.01 | |||
> '--+--||--, ,----------------|---------(O)--------, |||
> | | | | + sense \ |||
> __|__ 2k7 562 ,-----+ '--+++
> | | | | | | 2200uF |||
> | |---+----+ 1.5 |+ 6V QUAD PENTIUM
> |_____| 1.25V | 10W === |||
> | 1k24 | | ,--+++
> | LMV431 | | | - sense / |||
> '-----------+----------|-----|------+--(o)--------' |||
> RETURN | | | |||
> ,--(o)-------------------+-----+--33--' |||
> ==+========================================================'''
>
> Circuit Notes: Twenty-eight places 2n5686 or equivalent NPN TO-3, mounted
> on a pair of isolated leaf-blower heat sinks, with thin heat-sink grease,
> and no insulating pads; each heat sink dissipates about 4kW at 250A> and
> 5kW under 300A short circuit condition. Each resistor bank dissipates up
> to 0.7kW.
Well, gotta run, my wife's replanting a big orange tree.
Thanks,
- Win