Re: Power Supply

> 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.!

>

I suspect that the newer units, to keep size down below the size of a
buffalo head, are using switching type power supplies to convert the
lines into the bulk DC. Toroids make sense for that configuration or
where there is not enough room to distance the magnetic components a
few inches apart. Low frequency transmits poorly through the air and
the nice gentle transitions of the AC sinewave create no high
frequency transients. It is true that the ground in a system can be
a source to transmit noise and the ground loops are the bane of
designers. With proper filtering on the bulk DC (low AND high
frequency bypass) the only noise from a normal 60HZ supply is not
normally a concern. If I were a manufacturer and I could build
whatever I wanted, a switching front end supply with a nice little
molded E core or toroid would allow me to product a light and
efficient unit I could hold in my hand. A good 700W DC powersupply
with 60HZ magnetics is a chunk-o-iron! (expensive to ship). Of course
then I would have to deal with the high frequency noise from the
switching power supply...

I am getting a vision of the list member that is going to rewind his
toroids. By the time he finishes that project he will be completely
ready to pay someone else to build his next toroid with one of their
special coil winders! ;-)

As for the concept of building a triac or SCR non-transformer
isolated supply: Make sure your life insurance is paid up and your
family knows how to do CPR!

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