Re: [CAD_CAM_EDM_DRO] Cheap Power Supply was Re: low cost drivers

In a message dated 01-Jun-02 15:17:17 Central Daylight Time, asdf@...
writes:

> So how
> old is too old, what brands hold up better? And finally, what is the best
> new source, and should one buy two smaller ones than one large one.....
> example if one needs a 22,000 mfd @ 50 volts, would it be more economic to

I will TRY to make sense for you, but know: I am NOT a "degreed" electrical
engineer. I HAVE been "doin' it" for years, but someone EDUCATED like Mariss
is a much better source of REAL info. But I will try:

I would say if you can be SURE an electrolytic cap. is no older than ten
years, maybe even 15, it'd be OK for another five. IF not "stressed" in use.
(E.g., had a "working voltage" rating of 50, and you ran it on 49.9 volts,
continuously, with occasional "spikes" to 60 or 75 volts, not lasting over a
few milliseconds). Brands? Whew. That's kinda like saying "Which are
better Americans, Republicans or Democratz?" CD, Mallory come to mind. SO
many Pacific Rim names that are JUST as good, if not actually BETTER, that I
can't even bring one to mind! I must admit, if the cap WORKED for me, I
didn't pay much attention to the brand! A "bad" cap maker wouldn't LAST long
if his stuff went dead after 8 years! OR, had, say, 85% rated capacitance,
etc.

New source? Depends on the QUANTITIES you plan on buying! For
"onsey-twosey", Digikey, Jameco, JDR are fine. Probably most of the
advertisers in the back pages of the "popular" magazines. Local OEM
distributors, if you live in a city with more than, say, 150K people.

NO! ONE cap at some capacitance is cheaper than TWO at HALF that
capacitance! Even if the SPACE is abundant, the labor to mount and hook-up
two is MORE than twice the hassle! I mean for caps larger than, say, 500
µF/60 WV, particularly larger than, say, 2000 µF.

Lots a luck! If you have questions about lektrikul stuff like this you don't
wanna put on the whole list, try me direct. If I read your inquiry while I
am in a good mood, I will answer with civility.

Jan Rowland, old troll


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