Re: [CAD_CAM_EDM_DRO] Schematic help

In a message dated 3/9/2003 5:11:43 PM Central Standard Time,
jfolson4@... writes:

> Then the combined black and the combined white connect to their respective
> points on the rectifer bridge. Is this a
> correct asumption of this connection?
>

John:

Yes, assuming the manufacturer of the two "identical" transformers has
connected the black and white lead-wires to the SAME end (start of winding,
or END of winding) of the secondary-windings in BOTH transformers. These
colors ARE almost-CERTAINLY connected properly, so, "black to black" and
"white to white" would give you the SAME voltage, but permit you to draw
TWICE the current-rating of just ONE transformer.

Now, if you connected BLACK of ONE transformer to WHITE of the other, you'd
get TWICE the voltage (nearly 60 volts) from the remaining "ends", a BLACK
and a WHITE. NEVER connect those last-two also together, unless you are
ready to blow fuzes, ruin the two transformers, at least burn insulation, and
possibly set fire to property!

The latter connection would still give you ONLY the ampacity of ONE
transformer--just twice the VOLTAGE.

HOWEVER! ALL of the above statements ASSUME that you will first have the
"Beginning of windings" and the "Ends of windings" of the PRIMARIES correctly
polarized! That is, if these are colored or numbered, the SAME colors or
numbers of leads must be connected in PARALLEL, just as Mariss' schematic
shows. That is, if you had them "crossed", the "polarity" of those Black and
White wires discussed above for the two transformers would be OPPOSING, not
"same" in each! "Polarity" such as thought of for a DC power-supply,
including a flashlight-cell, is simply "+" and "-". The input and output of
a TRANSFORMER is AC, so that "polarity" changes 120 time per second in the
USA (100 times/sec. in most of the rest of the world). So, at any given
INSTANT, there is a "polarity" which must be correct for these connections we
are discussing.

If you need still more basic assistance with such, e-mail me direct, as we
will likely be scolded for carrying on a chat about "basic electronics", not
CNC machining! Sorry, List-Bosses!

Jan Rowland


[Non-text portions of this message have been removed]