89893Re: [mach1mach2cnc] Power supply caps
- Apr 3 12:35 AMHi, well there are formuleas and then there is good enough, and then cheap
enough....the best i can say is more capacitance wont hurt.....something
around 33,000 uf to 40,000 uf should be fine, however i want to see 60 volt
caps so unloaded the cap wont be overvolted...even a bit higher is a little
more safety margin........however more expense....
if i was building i would get 65 or 70 volts, and look for something
33,000uf or a few thousand more up to 40,000 uf..
once you get beyond 40,000 then you need to think about soft start.......to
limit the inrush current(turn on current).....
i am available most anytime to chat off line, i suspect its a power supply
for a cnc machine. cul brian f.
----- Original Message -----
From: "Andrey Lipavsky" <alipavsky@...>
Sent: Wednesday, April 02, 2008 10:59 PM
Subject: [mach1mach2cnc] Power supply caps
> I'm building a power supply and have a question on cap size.
> My toroidal transformer will supply 40V at 24A. Now, according to the
> standard cap formula, I would need roughly 30K-uf to sustain the 55VDC at
> 20A (derated to 80%).
> My question is why none of the over-the-counter power supplies in this VA
> bracket seem to use so much capacitance? Is this really overkill or are
> they just cutting corners?
> Andrey Lipavsky
> Essex Jewelers
> 490 E. McMillan St.
> Studio 205
> Cincinnati, OH 45206
> (513) 826-0240
> www.machsupport.com - Web site AccessYahoo! Groups Links
> No virus found in this incoming message.
> Checked by AVG.
> Version: 7.5.519 / Virus Database: 269.22.4/1355 - Release Date: 4/1/2008
- << Previous post in topic Next post in topic >>