Re: [CAD_CAM_EDM_DRO] Power Supply

In a message dated 29-Jul-02 22:12:31 Central Daylight Time,
tszaran@... writes:

> I was wondering why most stepper systems are using Toroid
> tranformers for the main V supplies. Is there any benefit to using
> that vs SCR's or Triac based supplies, or is it more of a convienence
>

Tom: The relatively-new TOROID transformer is a boon to "electrical nasties"
such as phantom electromagnetic racket, unwanted EM coupling, etc. Other
than a little extra money, a toroid-based power supply is "the WAY to go"!

I assume you are implying that you think SCR or Triac based supplies (like
light-dimmers?) would be an alternate source of lowered AC voltage for a PS.
NOT! All those semiconductors do to "full line-voltage" (120 or 240 VAC) is
"chop it up", letting only a "portion of time" through, so that the effective
power transmitted is lowered (thus, OK for a resistive lamp-dimmer
application). That "chopping up" is much, much more of an "electrical nasty"
than all the nekkid old pre-toroidal transformers (the "E-I kind") in the
world in one box!

I note professionally-manufactured stepper power-supplies/controls coming in,
now, with toroids, where they once had old "E-I" transformers, and these are
clearly an improvement in reduction of nebulous phantom steps, etc.!

Thought you might appreciate this opinion from an ignernt (non!-) "EE".
Jan Rowland


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