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From: D Yuniskis on 19 Apr 2010 22:53
Hi John,

John Larkin wrote:
> Can anybody suggest a good one?

You might check Analog Devices. I seem to recall they
had a fair bit of literature on the subject in the
late 70's (how much of this has survived is the issue).

We used to use them (made our own) in some avionics (?)
kit back then (AD was across the street :> ). I doubt
I have kept any of the literature that I had (at least,
not on *those* sorts of things! :> ) from that era.
From: Tim Wescott on 19 Apr 2010 23:50
John Larkin wrote:
> Can anybody suggest a good one?

Ha ha ha ha ha he he he he he ho ho ho ho ho aaaaaaaaaaaaaaaaagh!

(I'm not making fun of you here, that's hysterical laughter).

Call Renco Encoders and see if you can sweet-talk them out of a copy of
"Feedback Devices in Motion Control Systems", by Robert M. Setbacken.

Then call Moog Components -- wade through the Moog website and find the
guys that sell the precision industrial and aerospace encoders. Sweet
talk them, too.

Be aware that all the electronics whizzes who worked on encoders have
died of old age -- it's all mechanical engineers; they know bearings,
they know winding machines, and they know how to test things, but when
you start asking questions about impedance vs. frequency and other
seemingly obvious things the best you'll get is a friendly shrug.

They're variable transformers. They're really inefficient. Their
impedance is pretty close to the wiring resistance plus the inductance
times radian frequency (no surprise there). They work over an
astonishingly large frequency range, although they are traditionally
only specified at the frequency that the first customer wanted to use.
The drive amplitude is specified in voltage, although if you read
between the lines they're limiting the I^2R losses in the primary. Try
to ask the guys who design them these days and at best you'll get a
friendly shrug...

You can order them specified for other frequencies, or sizes, for "some"
NRE. "Some" is relative, and Moog is an aerospace company...

How tightly are you gonna simulate the resolvers? Just behavioral?
1st-order with inductances and winding resistance? Parallel
capacitance? Electrical nonlinear effects? Spatial nonlinear effects?
Are you gonna simulate multi-speed resolvers?

There's probably a market for a general-purpose resolver simulator, and
possibly even more so for a general-purpose resolver _meter_ (I recall
looking and not finding one, at a time that one was desperately needed).

But there's lots of metrology issues to overcome if you want the meter
or simulator to exceed the accuracy that you can get from a resolver --
the really good ones work down to arc seconds, which is "don't breath"
territory if you want to check out the physical system.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
From: Rich Webb on 20 Apr 2010 19:59
On Mon, 19 Apr 2010 16:58:15 -0700, John Larkin
<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote:

>
>Can anybody suggest a good one?

Hop over to DDC Corporation http://www.ddc-web.com/ and navigate down to
http://www.ddc-web.com/FileLibrary/GenericDocs.aspx. Pick up a copy of
their "Synchro/Resolver Conversion Handbook." DDC are the go-to guys for
a cubic butt-ton of Navy synchros and S/D & D/S converters and the
handbook contains quite a lot of good general info.

There's also a NEETS training module on synchro/servo/resolvers over at
http://www.tpub.com/content/neets/14187/

--
Rich Webb Norfolk, VA
From: John Larkin on 20 Apr 2010 22:11
On Tue, 20 Apr 2010 19:59:18 -0400, Rich Webb
<bbew.ar(a)mapson.nozirev.ten> wrote:

>On Mon, 19 Apr 2010 16:58:15 -0700, John Larkin
><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote:
>
>>
>>Can anybody suggest a good one?
>
>Hop over to DDC Corporation http://www.ddc-web.com/ and navigate down to
>http://www.ddc-web.com/FileLibrary/GenericDocs.aspx. Pick up a copy of
>their "Synchro/Resolver Conversion Handbook." DDC are the go-to guys for
>a cubic butt-ton of Navy synchros and S/D & D/S converters and the
>handbook contains quite a lot of good general info.
>
>There's also a NEETS training module on synchro/servo/resolvers over at
>http://www.tpub.com/content/neets/14187/


I stumbled across pdfgeni.com, a pdf search engine, and found this
page...

http://www.pdfgeni.com/book/synchro-handbook-pdf.html

which includes a bunch of the DDC stuff.

John

From: JosephKK on 24 Apr 2010 06:32
On Mon, 19 Apr 2010 17:31:31 -0700, John Larkin
<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote:

>On Mon, 19 Apr 2010 17:24:14 -0700, VWWall <vwall(a)large.invalid>
>wrote:
>
>>John Larkin wrote:
>>> Can anybody suggest a good one?
>>>
>>For their use in old time systems, Rad Lab Series Vol.21.
>
>I have that. And most of the other books don't seem to be much newer!
>
>>
>>If you need to connect between a synchro and a resolver, use a Scott-T
>>transformer. :-)
>
>An expensive transformer seems to be a silly way to do a little trig.
>Adding another multiply to an ARM program costs ... calculates
>furiously ... $0.00.
>
>I'm contemplating designing an LVDT/synchro/resolver simulator. The
>sensible way seems to be to digitize the excitation voltage and make
>the various winding voltages with DACs, and do all the rest in a uP or
>FPGA.
>
>John
>

I am presuming that you have the wit to digitize ratiometrically between
the excitation and the output(s). Then the fancy transformers are
unnecessary.

And all the decent books i knew of were Military tech training manuals
from the 1970s and earlier. It is not that complex but it has some
twists.
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