On Wed, Feb 15, 2006 at 01:10:36PM +0000, Howard Winter wrote:
> On Tue, 14 Feb 2006 22:32:48 -0500, Peter Todd wrote:
> >...
> > I built a linear power supply using a 28A
> > 6.3V transformer from digikey. 237-1255-ND. 4x LM396K 10A regulators in
> > parallel through load-sharing resistors regulate the voltage. For my
> > first attempt I used a standard 50A 600V diode bridge, MP506W-BPMS-ND
> 
> You haven't mentioned capacitors - hopefully you have some huge electrolytics across the output of the 
> bridge-rectifier?

Relatively large electrolytes, one 100,000uF, 25V unit. I did check if
there was any ripple present, if I recall correctly it worked out to be
about 0.05Vpp ripple when everything was running.

> > I ordered three 115CNQ015ASL-ND 15V 110A
> 
> 15V doesn't sound like much headroom above the supply - the 6.3V is RMS, so you'll be getting peaks of about 
> 9V.  Added to that, the 6.3V is what it will give when fully loaded - at lower loads the voltage will rise.  
> Without detailed specs I don't know how high that would be, but it *could* be enough to exceed the diodes' 
> reverse voltage rating when the motors all happen to go quiet together.

Hmm... Sounds quite plausable allright, and as I mentioned to antoher
poster, it looks liek the 15V can be much less under the right
circumstances.

-- 
pete@petertodd.ca http://www.petertodd.ca
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