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

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