Re: Re: Resolvers vs Encoders

Jon

The need for the small encoder is the product of trying to use the
existing feedback packages with the Hardinge Lathe. This would only be a
problem if you wanted to use the existing GE drive amps which require
tach feedback. If you used newer servo amps that derive velocity from
position you would not have this problem and could use any diameter
encoder up to 3 inch.

Yes, I believe that you might be able to fit a 1 inch diameter encoder in
the feedback package where the resolver was. Three problems spring
immediately to mind. Finding a drive gear for it's shaft, making an
eccentric collar so that the gears can be adjusted, and being certain
that the encoder's bearings can handle the the radial force required to
drive it. The existing tach and resolver also have a small groove around
them near the drive end that is used to mount them to the feedback
package.

This would not be an easy conversion and make the cost of the chip based
resolver to pulse coder solution attractive -- or replace the drive amps
as well as the feedback.

Ray

On Thursday 24 October 2002 06:16 am, you wrote:
> Message: 17
>    Date: Thu, 24 Oct 2002 00:34:52 -0500
>    From: Jon Elson <elson@...>
> Subject: Re: Resolvers vs Encoders
>
> Dave Engvall wrote:
> >On 10/21/02 3:19 PM, "doug king" <evelle97530@...> wrote:
> >Hi all,
> >Ray Henry and I had considerable discussion about resolvers on
> > Hardinge lathes as he has several. Space seems a little limited; the
> > resolvers are geared off the shaft but the main problem is
> > space....only about an inch. Once could always custom make an encoder
> > from US Digital parts that would work.
> >The alternative would seems to be to look at the Analog Devices
> > resolver to digital converter. Not too expensive.
> >
> > 
>
> Gee, I thought the 2S80 series ran about $100, and the older 1S80
> series needed several chips
> that cost $50+ each.
>
> I have 3 Sumtak encoders that are barely 1" diameter.  That is a 3
> channel (ABZ) differential
> encoder, with 1000 cycles/rev.  I'm sure some other outfits make
> similar miniature encoders.
> (No, I can't sell them, they are on my mill, but they are VERY nice and
> compact units.)
>
> Jon