I Need A (Big) Rectifier

[MicroE]

I need a rectifier and a 1N4004 diode just won't cut it. I've never bought one this big before so I need a person that is knowledgeable about big rectifiers.

Output:
0 to 12 Volts DC
600 Amps, minimum.
Less than 5% ripple.
Air-cooled.

Input: 230V 3-phase

I thought about putting this post in B/S/T, but I believe that the Electronics forum has a better chance of reaching any CPF members that are in the industrial equipment business. All things being equal, I would rather buy from a CPF'er.---Marc

P.S. - Some people would call this machine a variable voltage DC power supply, but in our business we simply refer to them as "rectifiers".

 

[James S]

Well, you're not going to find anything at the consumer level that can do that /ubbthreads/images/graemlins/wink.gif The closest you'll find is a heavy duty arc welder. These can supply the amperage at around that voltage (I think they may be even lower voltage though) but I think are ususally AC output.

Also you won't find much in the consumer space that uses 3 phase power either.

You might try asking over at another one of my favorite BBS's on the web:

http://4hv.org/?op=forum

There are some people there that know a bit more about high power applications /ubbthreads/images/graemlins/grin.gif

Now that you've posted this, you have to cough up the info on just what the heck you're going to use it for. You could run about 2400 luxeons off that /ubbthreads/images/graemlins/smile.gif That would be something to see...

 

[Doug S]

[ QUOTE ]
MicroE said:
I need a rectifier and a 1N4004 diode just won't cut it. I've never bought one this big before so I need a person that is knowledgeable about big rectifiers.

Output:
0 to 12 Volts DC
600 Amps, minimum.
Less than 5% ripple.
Air-cooled.

Input: 230V 3-phase

I thought about putting this post in B/S/T, but I believe that the Electronics forum has a better chance of reaching any CPF members that are in the industrial equipment business. All things being equal, I would rather buy from a CPF'er.---Marc

P.S. - Some people would call this machine a variable voltage DC power supply, but in our business we simply refer to them as "rectifiers".

[/ QUOTE ]
Diodes in that current range are usually the "hockey puck" style. You should be able to find some that meet your needs on the IRF site

IRF

 

[JSWrightOC]

I thought most welders were DC, because the AC currents would cause weird or otherwise undesirable formations in the weld. At least I believe most welders give you the option of -, +, or AC.

Yes, please tell us what you're building!!!

 

[Tomas]

I do believe that most welders offer DC output, but at about 100% ripple ...

I used rectifiers easily in that current range (from Lorain, for example) but all of them I used to spec. were fixed voltage (24, 48, 130, etc.) rather than variable. (I also had things like up to 40,000Ah of battery plant to "filter" the ripple to better than -90dB.)

An 800A, 48VDC rectifier was about the size of two kitchen ranges stacked attop one another, and was normally fed 660V, 3Phase power. Smaller ones with about the capacity/voltage you want would be maybe a quarter that size, but the addition of "variable" might increase it to rather large, again.

I really can't imagine a "variable" output plant in that range, but I'm sure they make 'em, somewhere ...

Good luck!

 

[Doug Owen]

[ QUOTE ]
MicroE said:
I need a rectifier and a 1N4004 diode just won't cut it. I've never bought one this big before so I need a person that is knowledgeable about big rectifiers.

Output:
0 to 12 Volts DC
600 Amps, minimum.
Less than 5% ripple.
Air-cooled.

Input: 230V 3-phase



[/ QUOTE ]

If I understand what you're after, an interesting prospect. What's the application?

A possible solution might be as others have suggested commercial welders. Specifically, there's a unit I used to maintain years ago that looked like a bathtub size propane tank on wheels. It was a horizontal motor/generator with various taps (including 208 three phase, what I assume you meant?) for input voltage. It used field control and output zero to 600 Amps DC through six inch wide, inch think carbon brushes.

In straight up supplies, I've never worked past 500 A (although that was into two half ohm magnet coils, 250 volts out on that 500 A....). IIRC it's 12% ripple 'barefoot' on three phase, at this level you'll need a truckload of capacitor or a medium serious inductor or be willing to give up (and deal with) a lot of losses in a pass element.

Switchers I've known in this current range have been limited to 5 Volts (still a serious beast at two kW in), two or three of them would be a pile as well, but would do the defined job.

Three 'solutions', what's the problem?

Doug Owen

 

[MicroE]

Oh, come on. The application is easy: electro-polishing.
You immerse a piece of metal in a conductive liquid (water plus sulfuric acid, for instance) and then run A LOT of current through the piece of metal. It is electro-chemically etched.
Thanks for all of the suggestions.---Marc

 

[Doug Owen]

[ QUOTE ]
MicroE said:
Oh, come on. The application is easy: electro-polishing.
You immerse a piece of metal in a conductive liquid (water plus sulfuric acid, for instance) and then run A LOT of current through the piece of metal. It is electro-chemically etched.
Thanks for all of the suggestions.---Marc

[/ QUOTE ]

That's some serious electropolishing. At my day job, it's miliamps and dozens of Volts. Then again it's 3 mm electron microscope specimens we're doing.....

Bummer part is the solutions are acids and alcohols. A common one is nitric acid and methanol (AKA rocket fuel.....). Some use hydrofluoric, really nasty stuff, or perchloric (explosive when dry). You cool it off with liquid nitrogen so it takes say 2 minutes to eat through the foil, then run for 115 seconds, the result is only a few dozen atoms thick. Eventually.....

I'd look to DC welder technologies for sure. Maybe big battery chargers?

Doug Owen

 

[MacGyver]

[ QUOTE ]
Tomas said:
I do believe that most welders offer DC output, but at about 100% ripple ...

I used rectifiers easily in that current range (from Lorain, for example) but all of them I used to spec. were fixed voltage (24, 48, 130, etc.) rather than variable. (I also had things like up to 40,000Ah of battery plant to "filter" the ripple to better than -90dB.)

An 800A, 48VDC rectifier was about the size of two kitchen ranges stacked attop one another, and was normally fed 660V, 3Phase power. Smaller ones with about the capacity/voltage you want would be maybe a quarter that size, but the addition of "variable" might increase it to rather large, again.

I really can't imagine a "variable" output plant in that range, but I'm sure they make 'em, somewhere ...

Good luck!

[/ QUOTE ]

I work for Lorain!! Well, now it's actually www.marconi.com but same company /ubbthreads/images/graemlins/smile.gif
Voltage adjustments on our rectifiers are limited to a few volts above or below the output spec (most commonly 24 or 48V as Thomas noted). The variable power supplies we use in our repair facility are <100A, and aren't made by us LoL.
We did sell some small 12V 50A supplies years ago but they are no longer offered, plus quite honestly our products are prohibitively expensive for non-commercial applications. /ubbthreads/images/graemlins/broke.gif

I agree your best bet (easiest & cheapest) may be pursueing the welder or automotive battery charger routes.

 

[mattheww50]

I don't think a battery charger is going to helpful, they tend to have minimal filtering, so the 5% ripple is likely to be a problem. My own advice would be to talk to one of the big power supply houses, ASTEC, Condor, Power-One.

Earlier in my career (1970's) we used ganged supplies, a master and 2 slaves. The provided 5 volts at 500 amps (Conducted to the mainframe CPU by a solid copper bus bar somewhat larger then your thumb!

The bind I see is the really big stuff is 48V only (means it is designed to run telephone gear).

For the kind of power your are looking at, and voltage needs, it may be worth looking at rotating machine solutions (M-G sets) as opposed to an all electronic solution.

 

[Tomas]

(Sorry, Marc, this is a bit off topic, but ... )

MacGyver, one thing I always liked about the Lorain stuff was it's near absolute reliability. Expensive, yes, but VERY solid products.

There were other products (Reliance comes to mind - I replaced a number of those with Lorain) but I learned from experience to stick with the best stuff. The one time I had problems with Lorain units (a half dozen little high-frequency 50A, -48V rack-mount units, IIRC) Lorain had spares and a guy there the next morning and got us sorted out with no service interruptions.

When an equipment failure is measured in hundreds-of-thousands-of-dollars-per-minute, only the best gear is good enough. /ubbthreads/images/graemlins/grin.gif

I like products that just sit quietly in the corner and do what they are supposed to do. /ubbthreads/images/graemlins/thumbsup.gif

 

[NikolaTesla]

HOW big? How many volts? How many amps? How much ripple on the DC? My company can make you one. 6Kv At 6 Ka. is that enough? /ubbthreads/images/graemlins/grin.gif

 

[Tweek]

Hah! 36 miiiilion (Dr. Evil voice) watts!

Got a substation in your backyard? /ubbthreads/images/graemlins/grin.gif


Chris

 

[Marked]

http://www.dynapower.com/

http://www.google.com/search?num=20&hl=en&ie=UTF-8&oe=UTF-8&safe=off&q=electropolishing+Power+Supplies+&spell=1

 

[Clifton Arnold]

I belive that your best bet would be to check out an electro-plater plant. There they use rectifiers that are
variable voltage and current. The only one in the area that I know of personaly is Lincoln Plating Corp. in Lincoln NE.