Re: [CAD_CAM_EDM_DRO] Spherosyn

majorityuk2000 wrote:

>Has anyone looked at making Spherosyn type encoders and electronics, or
>know of any designs for them, please?
>
>

I suppose you could look up the Newall patents and try to
make one. It gives quadrature output at twice the period
of the balls, so if you use 1/4" balls, you get a resolution of
1/8". Everything beyond that is done by interpolating. That's
why the exact design of the coils in the sensing head is REALLY
critical, because they are sub-interpolating the the balls to a
high degree.

Once you have the exciting and sense coils worked out, you
could probably use the Analog Devices AD2S1200 resolver to
digital converter. I think you'd end up with a resolution of
.000122" if you can get the magnetics linear enough.

You need to use magnetic steel balls in an aluminum or non-magnetic
stainless tube. If the balls get magnetized, even the Newall scales
become inaccurate.

Jon