Re: Yet another power supply question

--- In CAD_CAM_EDM_DRO@y..., "jbolt001" <js3mc@a...> wrote:
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> Hi Mariss,
>
> > (2) It makes no difference whether the transformer is torroidal
> > or "E,I" core (standard transformer). Use whatever gives the
> required
> > current at the voltage you need. A 24V (RMS) secondary is a good
> > choice.
>
> My consideration for the torroidal trasformer is size. This may not
> be an issue yet but I would like to know what a comparable one
would
> be.
>
If you comparable electrically, go with the current and voltage you
need. The two multiplied together give you the VA of the xformer. The
bigger the number, the bigger the xformer.
>
>
> > (4) A 50VDC rated cap is the correct, most economical choice. The
> > capacitor is what is called an aluminum electrolytic. Use the
kind
> > that have the two threaded (10-32) terminal posts. Be sure to
mind
> > the polarity. One post will be marked with a "+" sign, make sure
> > the "+" output of your bridge rectifier goes there.
>
> Any brand recommendation? I searched a couple of online shops but I
> cannot tell what the terminals are.
>
Brand makes no difference to me. The kind you need are often
called "computer grade" capacitors. Also, when a cap is this size, it
can't be PC mounted so it will have the screw-post terminals. Get the
mounting bracket as well. It makes life easier.
>
> > (5) Use a 25A 100V rated bridge. They cost just about the same
and
> > will run a little cooler. Use a little heatsink compound
underneath
> > it when you mount it to the chassis.
>
> What case style will this be for chasis mounting? I'm amazed at the
> huge number of variations of the electronics.
>
The kind you want are about 1.5" by 1.5", have a metal base, spade
terminals on the 4 corners and have a hole in the middle that takes a
10-32 mounting screw.
>
> > (6) Use as heavy or heavier wire guage as what your transformer
> leads
> > are. Stranded wire of course. Use two different wire colors to go
> to
> > the drives. Red for "+", black for "ground". If you can't, use a
> > lighter color for "+". This will avoid mixing the two up and
> > destroying the drives.
>
> Ok ok I'm not THAT electronicly challenged. I work in the
> construction industry and I'm always amused when some EE attempts
to
> do some household wiring and can't understand what the white wire
is
> for and why the breaker keeps tripping because the black wire is
> connected to the ground. Thanks for the info.
>
Yeah, nature taught me to respect the difference between the black
wire and the white one (white good, black hurt!).

Mariss
>
> Jay