Re: [CAD_CAM_EDM_DRO] Why don't we use ferrites??

Would op-amp based active filters provide better
performance and lower cost?

Chris


--- Jon Elson <elson@...> wrote:

> tauscnc wrote:
>
> > Hey all,
> > When I pulled apart an old scanner and printer I
> kept finding these
> > metal tubes that have wires wriped around them
> before going to their
> > final place. I also find this on my digital camers
> wire and other
> > wires that connect to the computer. I later found
> they are
> > called "Ferrites" and are used to decrease noise.
> >
> > Why don't we use them in our stuff, like the
> camtronics board or the
> > wires going from the drivers to the steppers?
>
> I put a 2-pole output filter in my servo amps to
> remove unwanted EMI
> signals from the motor output. This is the same
> problem that any
> bipolar chopping-type stepper driver would produce.
> For cost reasons,
> they usually leave out the filter. I can even use
> an AM radio near the
> CNC machine. But, I will note that the output
> filter adds up to be the most
> expensive part of the whole unit. Ferrite beads
> won't do the job. I had
> to use 4 J. W. Miller toroid inductors that cost
> about $12 each.
>
> Jon
>
>
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