What is this strange encoder motor?

I

Ignoramus18921

Guest
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

Thanks
 
On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".
Click to expand...
My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
On 2010-08-03, Tim Wescott <tim@seemywebsite.com> wrote:
On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.
Click to expand...
There are some converters out there, Jon has one for sale too.

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

If this is too complicated, I may just look for the right sized modern
servo motor on ebay.


i
 
On 2010-08-03, Ignoramus18921 <ignoramus18921@NOSPAM.18921.invalid> wrote:
On 2010-08-03, Tim Wescott <tim@seemywebsite.com> wrote:
On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.


There are some converters out there, Jon has one for sale too.

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

If this is too complicated, I may just look for the right sized modern
servo motor on ebay.
Click to expand...
I forgot to add, or make a shaft adaptor if it is at all possible, and
mount an encoder.

i
 
I had a second look at the motor.

http://tinyurl.com/2vagsc7

You can see the rear end (ODE) of the motor shaft. It is kind of
roughly machined, as if cut off with a hacksaw or something.

If a recolver converter is not practical here for any reason, I think
that simply mounting a US digital E5 encoder on the back may be the
best option of all.

I think that it is a simple machining exercise to flatten that side,
locate a center and precisely drill a hole in the shaft (precisely,
here, means under 0.005" error) along the axis of rotation. Then I
would tap it and use a shoulder bolt with the head cut off, to mount
the encoder wheel.

If it does not fit under the cover, I will make a bigger cover from
aluminum.

i
 
"Ignoramus18921" <ignoramus18921@NOSPAM.18921.invalid> wrote in message
news:-6ednaefZKBHxMrRnZ2dnUVZ_hCdnZ2d@giganews.com...
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/


Does anyone have AN idea just what are they and whether I can use it
as a quadrature encoder.
Click to expand...

yes. And No
 
On 08/02/2010 08:09 PM, Ignoramus18921 wrote:
I had a second look at the motor.

http://tinyurl.com/2vagsc7

You can see the rear end (ODE) of the motor shaft. It is kind of
roughly machined, as if cut off with a hacksaw or something.

If a recolver converter is not practical here for any reason, I think
that simply mounting a US digital E5 encoder on the back may be the
best option of all.

I think that it is a simple machining exercise to flatten that side,
locate a center and precisely drill a hole in the shaft (precisely,
here, means under 0.005" error) along the axis of rotation. Then I
would tap it and use a shoulder bolt with the head cut off, to mount
the encoder wheel.

If it does not fit under the cover, I will make a bigger cover from
aluminum.
Click to expand...
Threads don't make a good center reference, in my limited experience.

I would bore the hole for the threads, then counter-bore and ream to a
light press fit of some handy drill rod. Then I'd make a bushing out of
the handy drill rod and press it (lightly) into the hole. Then I'd say
"whoa, look! a stepped shaft!" and I'd bolt an encoder disk to it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
On 08/02/2010 06:48 PM, Ignoramus18921 wrote:
On 2010-08-03, Tim Wescott<tim@seemywebsite.com> wrote:
On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.


There are some converters out there, Jon has one for sale too.

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?
Click to expand...
Um -- pretty damn good?

It's hard to say, because it varies with the resolver. But I'd expect
anywhere between one and ten minutes of an arc (no, you don't get
dimensions in degrees, or counts, when you're dealing with resolvers).
Resolvers that do better than that generally go to "multi-speed" units,
with a "high-speed" resolver that repeats itself 8, 16, or 32 times
around the circle, and a "low-speed" (1x) resolver to tell you what
quadrant of the high-speed resolver you're looking at.

If this is too complicated, I may just look for the right sized modern
servo motor on ebay.
Click to expand...
Aw, what's the fun in that?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
On 2010-08-03, Tim Wescott <tim@seemywebsite.com> wrote:
On 08/02/2010 06:48 PM, Ignoramus18921 wrote:
On 2010-08-03, Tim Wescott<tim@seemywebsite.com> wrote:
On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened 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 think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, 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 it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.


There are some converters out there, Jon has one for sale too.

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

Um -- pretty damn good?

It's hard to say, because it varies with the resolver. But I'd expect
anywhere between one and ten minutes of an arc (no, you don't get
dimensions in degrees, or counts, when you're dealing with resolvers).
Resolvers that do better than that generally go to "multi-speed" units,
with a "high-speed" resolver that repeats itself 8, 16, or 32 times
around the circle, and a "low-speed" (1x) resolver to tell you what
quadrant of the high-speed resolver you're looking at.
Click to expand...
Say, ten minutes of arc, gives you 360*6 = 2160 units of resolution
per circle. Very good in my view. Certainly enough in a geared way
down rotary table.

If this is too complicated, I may just look for the right sized modern
servo motor on ebay.

Aw, what's the fun in that?
Click to expand...
I am having enough fun as it goes. I want some uncomplicated
solutions.

I have seen people having too much fun with unfinished machines
sitting for years. The second addiction is being too cheap. $30 servo
drives are not cheap enough for them, so they sit and wait until they
can find $5 servo drives or "make their own" from stuff they find in
dumpsters.

The first approach (too much fun) has some advantages, but
disadvantages are big enough, in my view, to not go there.

The second approach is uneconomical, if you are smart to make your own
servo drives it is better to buy one and make money doing something
more economically valuable.

i
milling out a bigger mold than yesterday and standing in front of EMC
 
....
I would bore the hole for the threads, then counter-bore and ream to a
light press fit of some handy drill rod. Then I'd make a bushing out of
the handy drill rod and press it (lightly) into the hole. Then I'd say
"whoa, look! a stepped shaft!" and I'd bolt an encoder disk to it.
Click to expand...
This is the best route to go. I did this to a 7.5 hp lathe spindle motor.

Karl
 
On 2010-08-03, Karl Townsend <karltownsend.NOT@embarqmail.com> wrote:
...
I would bore the hole for the threads, then counter-bore and ream to a
light press fit of some handy drill rod. Then I'd make a bushing out of
the handy drill rod and press it (lightly) into the hole. Then I'd say
"whoa, look! a stepped shaft!" and I'd bolt an encoder disk to it.


This is the best route to go. I did this to a 7.5 hp lathe spindle motor.
Click to expand...
Should be one evening's job with this little servo motor.

How would I pick a drill and reamer to make a press fit hole for, say,
a 1/4" shaft?

Say, McMaster has two reamers, 0.248" and 0.2495", for a 1/4" dowel
pin. Which one should I use?

i
 
Ignoramus30076 <ignoramus30076@NOSPAM.30076.invalid> fired this volley in
news:VsOdnUImjYrDY8rRnZ2dnUVZ_gydnZ2d@giganews.com:

Say, McMaster has two reamers, 0.248" and 0.2495", for a 1/4" dowel
pin. Which one should I use?
Click to expand...
If you use the small one, at only 1/4", it'll take a lot of heat to get
the hole to expand that one thou or so you'll have left to go. You'll
also have to work with confidence and speed when you press it on.

Some guys would use the larger one, and a drop of Loctite to secure the
joint. It won't be under any significant load.

Just for G.P.s, I'd figure getting a .250+ hole out of the .2495 reamer
unless _everything_ in the setup was spot-on.

One trick is to heat the work before reaming with the optimum-size reamer
(and keep it hot during reaming, so it doesn't seize up on the tool).
When the piece cools, it will be exactly the amount undersized to fit up
the way you want.



LLoyd
 
On 2010-08-03, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:
Ignoramus30076 <ignoramus30076@NOSPAM.30076.invalid> fired this volley in
news:VsOdnUImjYrDY8rRnZ2dnUVZ_gydnZ2d@giganews.com:

Say, McMaster has two reamers, 0.248" and 0.2495", for a 1/4" dowel
pin. Which one should I use?

If you use the small one, at only 1/4", it'll take a lot of heat to get
the hole to expand that one thou or so you'll have left to go. You'll
also have to work with confidence and speed when you press it on.

Some guys would use the larger one, and a drop of Loctite to secure the
joint. It won't be under any significant load.

Just for G.P.s, I'd figure getting a .250+ hole out of the .2495 reamer
unless _everything_ in the setup was spot-on.

One trick is to heat the work before reaming with the optimum-size reamer
(and keep it hot during reaming, so it doesn't seize up on the tool).
When the piece cools, it will be exactly the amount undersized to fit up
the way you want.
Click to expand...
Lloyd, I cannot heat it, it is a motor shaft mounted in the motor.

I think that .2495 and loctite would be perfect.

So, .2495 reamer, 1/4" dowel pin, and what drill should I use for
initial drilling of the hole?

i
 
Ignoramus30076 <ignoramus30076@NOSPAM.30076.invalid> fired this volley in
news:ltydnfJvi6Ojl8XRnZ2dnUVZ_oadnZ2d@giganews.com:

So, .2495 reamer, 1/4" dowel pin, and what drill should I use for
initial drilling of the hole?
Click to expand...
Unless that's a really short-shafted "pancake" motor, you're going to
play hell setting it up to run true for the initial spotting, unless
you've got enough shaft sticking out to mount the outboard end in a
steady rest.

For that purpose, you should use a short, stiff "spotting drill". A
center drill will work. But if you want the hole not only true in size,
but also perfectly centered in the work, you should bore it to reaming
size, not drill it. (pre-drill, of course...) That's a teensy boring
tool.

Somehow, I envisioned turning a "hub" type shaft extension, and pressing
it ONTO rather than INTO the motor shaft. That would be a lot more
accurate to set up and make, and wouln't involve modifying the motor
itself (along with the concomittant problems of getting a heavy weight on
a relatively long spindle to run true in total overhang.

If you did it the way I envisioned, then you could even mount the whole
affair between centers after joining, to true everything up and finish
the stub shaft to size.

LLoyd


LLoyd
 
On 2010-08-03, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:
Ignoramus30076 <ignoramus30076@NOSPAM.30076.invalid> fired this volley in
news:ltydnfJvi6Ojl8XRnZ2dnUVZ_oadnZ2d@giganews.com:

So, .2495 reamer, 1/4" dowel pin, and what drill should I use for
initial drilling of the hole?

Unless that's a really short-shafted "pancake" motor, you're going to
play hell setting it up to run true for the initial spotting, unless
you've got enough shaft sticking out to mount the outboard end in a
steady rest.

For that purpose, you should use a short, stiff "spotting drill". A
center drill will work. But if you want the hole not only true in size,
but also perfectly centered in the work, you should bore it to reaming
size, not drill it. (pre-drill, of course...) That's a teensy boring
tool.
Click to expand...
I can have up to 0.01" shaft error.

Somehow, I envisioned turning a "hub" type shaft extension, and pressing
it ONTO rather than INTO the motor shaft.
Click to expand...
I cannot do it, the shaft sticks out only by 1 mm or so.

That would be a lot more accurate to set up and make, and wouln't
involve modifying the motor itself (along with the concomittant
problems of getting a heavy weight on a relatively long spindle to
run true in total overhang.
Click to expand...
I would do it on a mill, not on a lathe. 0.01" is not space age
accuracy, I think that I can do it.

If you did it the way I envisioned, then you could even mount the whole
affair between centers after joining, to true everything up and finish
the stub shaft to size.
Click to expand...
 
On Mon, 02 Aug 2010 17:56:29 -0700, Tim Wescott wrote:

My educated guess is that it is a resolver.
Click to expand...
That's exactly what it is. Would be a three phase motor to give the
electronics part of the Machinery precise info on speed and position
by calculating phase angles and such. Every CNC machine has them in one
form or another.
 
Ignoramus18921 wrote:

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

The AD2S1200 converter chip I use in my converter board gives 4096
Click to expand...
quadrature counts/rev, with an index pulse.

Jon
 
On 2010-08-03, Jon Elson <jmelson@wustl.edu> wrote:
Ignoramus18921 wrote:

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

The AD2S1200 converter chip I use in my converter board gives 4096
quadrature counts/rev, with an index pulse.
Click to expand...
Sounds like a luxury item.

I already bought this converter from you. Things seemingly are going
well.

Igor
 
Tim Wescott wrote:
I would bore the hole for the threads
Click to expand...
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?
 
On Aug 3, 8:23 am, Ignoramus30076 <ignoramus30...@NOSPAM.
30076.invalid> wrote:
On 2010-08-03, Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:





Ignoramus30076 <ignoramus30...@NOSPAM.30076.invalid> fired this volley in
news:VsOdnUImjYrDY8rRnZ2dnUVZ_gydnZ2d@giganews.com:

Say, McMaster has two reamers, 0.248" and 0.2495", for a 1/4" dowel
pin. Which one should I use?

If you use the small one, at only 1/4", it'll take a lot of heat to get
the hole to expand that one thou or so you'll have left to go.  You'll
also have to work with confidence and speed when you press it on.

Some guys would use the larger one, and a drop of Loctite to secure the
joint. It won't be under any significant load.

Just for G.P.s, I'd figure getting a .250+ hole out of the .2495 reamer
unless _everything_ in the setup was spot-on.

One trick is to heat the work before reaming with the optimum-size reamer
(and keep it hot during reaming, so it doesn't seize up on the tool).  
When the piece cools, it will be exactly the amount undersized to fit up
the way you want.

Lloyd, I cannot heat it, it is a motor shaft mounted in the motor.

I think that .2495 and loctite would be perfect.

So, .2495 reamer, 1/4" dowel pin, and what drill should I use for
initial drilling of the hole?

i-
Click to expand...
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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