What is this strange encoder motor?

Ignoramus18921 · 2010-08-02T23:50:50+00:00

Lots of new pictures here. is a servo motor driven rotary table Troyke U12PNC.I thought that it was a simple servo motor with a tachometer andencoder on the back. Nothing could be further from the truth. When Iopened it up, the tach was on the back alright, but no encoder. I took off a box hanging on the front of this contraption and I thinkthis is where the encoder is. There are two cylinders. One is called "Electro-craft moving coil tach generator". Part0100-00-022. The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500Hz, rotor 1 phase, stator 2 ph, spec code H.S.C.T., 11BRW-300-70/10."Does anyone have AN idea just what are they and whether I can use itas a quadrature encoder. On the rear of the motor, there is not enoug free hanging shaft tomount a modern encoder. My uneducated guess is that it is a "resolver".Thanks

Aug 02, 2010 24 Replies

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Jon Elson 16 years ago

same type of

some issues

An Inductosyn is similar in concept to a resolver, where a coil is energized with an AC field, and by varying magnetic coupling to other coils the position is detected. Inductosyn is a registered trademark of Farrand Controls, but their patent has run out. The classic Inductosyn has an exciting winding consisting of a serpentine trace on a PC board like material. Very close to this is another short piece with two serpentine traces of the same pitch a the spar. The two traces are offset by 1/4 of a pitch, to provide the quadrature relationship.

The problem with the Inductosyn is that it takes a LOT of drive current to provide a useful signal from the sense windings, often several amps of drive.

Jon

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Clifford Heath 16 years ago

And the easiest way to help get the hole concentric is to fix the drill bit and rotate the shaft in a lathe. Since you probably can't chuck the motor's armature, is is possible you could drill the hole using the motor's own power to rotate the shaft?

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pentagrid 16 years ago

I've had good results with precision shaft extensions by running the motor on it's own bearings. Chuck the motor housing in a 3 or 4 jaw chuck and support it near the shaft extension end with a 3 or 4 jaw steady.

With the motor running on it's own power bore and then press fit or locktite the extension shaft. Finish machine the fitted shaft on the same setup.

Jim

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Jim Wilkins 16 years ago

Unless the hardened dowel pin is necessary I would ream it 0.250" or whatever reamer I have and turn down a shaft to fit. When I do this sort of job I cut the shaft long and a few thousandths oversized and make short test cuts on the end, then turn the rest of the shaft to the size that fits and part the shaft to final length.

I found second-hand 0.4995" and 0.501" reamers which have worked well with drill rod for press and running fits on my home projects, such as the pivot pins on the front end loader.

jsw

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