Need sources for pot with planetary drive
 

Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor at
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

i remember these used to have slippage problems at the ball to shaft (after
a few hundred rotations) and required feedback looped mechanical drives to
accurately position anything they were used to control.

try something new!


"msg" wrote in message
...
Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor at
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

On Jul 13, 10:12 am, msg wrote:
Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor athttp://www.cybertheque.org/homebrew/rcvr/images/antennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Wow, I had seen those in the past but not for many many years.

If you are truly updating some rotators, there are some articles in
QST, CQ, 73, etc. from the past 20-30 years on doing it using
something other than 360-degree pots. Some of them use essentially
homebrew shaft encoders.

Tim.

Need sources for pot with planetary drive
 

On Jul 13, 8:02 am, "HapticZ" wrote:
i remember these used to have slippage problems at the ball to shaft (after
a few hundred rotations) and required feedback looped mechanical drives to
accurately position anything they were used to control.

try something new!

"msg" wrote in message

...

Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor at
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Regards,

Michael
msg _at_ cybertheque _dot_ org

I remember them, also, and the slippage. I used to lube them to make
them work better. They didn't.

I now know they must never be lubed and must be kept really clean.
They work because of the friction between the shaft, the ball and the
housing. Our pick-and place machine, used to place SMT components on
circuit boards, uses the same technology to convert rotary motion to
very accurate linear motion. The wheels and shaft must be kept very
clean, or we get positioning errors.

I have no clue about the current source of the devices, but probably
have a few in the junk box!

Paul, KD7HB

Need sources for pot with planetary drive
 

agreed, i have used pc mouse encoders with a hacked mouse circuit board for
various projects.

2 axis, three butttons , plenty of easy to use software, even write your
own visual basic

can even determine direction and speeds!

its all simple enough and uses standard rs232 ports.

mouse click buttons can be used to determine limit positions at extreme
points

the newer mice with some 6 or 7 variables can do lotsa stuff!



"Tim Shoppa" wrote in message
ups.com...
On Jul 13, 10:12 am, msg wrote:
Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor
athttp://www.cybertheque.org/homebrew/rcvr/images/antennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Wow, I had seen those in the past but not for many many years.

If you are truly updating some rotators, there are some articles in
QST, CQ, 73, etc. from the past 20-30 years on doing it using
something other than 360-degree pots. Some of them use essentially
homebrew shaft encoders.

Tim.

Need sources for pot with planetary drive
 

http://cgi.ebay.com/CTS-Potentiomete...-Bearing_W0QQi
temZ7595963466QQihZ017QQcategoryZ58164QQrdZ1QQssPa geNameZWD1VQQcmdZViewItem

try ebay search "ball potentiometer"


"msg" wrote in message
...
Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor at
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

msg wrote in news:139f22h91ghhna7
@corp.supernews.com:

I need the form factor for modifications to antenna
rotator assemblies

Do you mean the rotator or the controller?

For the rotator, you can maybe use a standard pot with gearing. I made an
old 3 wire rotator a 5 wire with a pot an a 4 to 3 gear. One gear was fixed
to the output shaft, the other to the pot, so that one full rotation (360
degrees) of the rotator shaft turned the pot its full path, or therabouts
(270 degrees). The controller just had a typical 270 degree pot and a 3/4
scale that rotated N-E-S-W-N.

Need sources for pot with planetary drive
 

On Jul 13, 7:12 am, msg wrote:
Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor athttp://www.cybertheque.org/homebrew/rcvr/images/antennas/pot.jpg
Resistance = 1K

Interesting. I've never seen a pot like this.

So the turns ratio is determined by the shaft diameter to ball
diameter ratio?
And the wiper arm is connected to the ball carrier?
So this assumes the metal to metal, shaft to ball won't slip, but the
ball will turn in the carrier, causing the carrier to have 1/3 the
rotation of the shaft?

Sorry, this doesn't help you at all...
Alan Nishioka

Need sources for pot with planetary drive
 

Gary Tait wrote:

msg wrote in news:139f22h91ghhna7
@corp.supernews.com:


I need the form factor for modifications to antenna
rotator assemblies


Do you mean the rotator or the controller?

For the rotator, you can maybe use a standard pot with gearing.
snip

I had considered gearing but the available space and the
necessary additional fabrication was more involved than
the solution I chose.

Here are photos of the modified rotor:

http://www.cybertheque.org/homebrew/...ntennas/rotor/

This rotor is common to a number of makes and models; the controller
that came with it was for the Cornell-Dubilier AR22R, an interrupter
based spring and escapement controller version.

The modifications permit continuous rotation and rely on the
controller to manage limits.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

msg wrote:

snip
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K
snip
Does anyone recognize this pot technology? Any suppliers
nowadays?

Thanks to all for replies so far.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

Jackson Brothers http://www.mainlinegroup.co.uk/jacksonbrothers/
Makes some excellent planetary drives. There are dealers in the USA.

Bill W0IYH

"msg" wrote in message
...
Gary Tait wrote:

msg wrote in news:139f22h91ghhna7
@corp.supernews.com:


I need the form factor for modifications to antenna
rotator assemblies


Do you mean the rotator or the controller?

For the rotator, you can maybe use a standard pot with gearing.
snip

I had considered gearing but the available space and the
necessary additional fabrication was more involved than
the solution I chose.

Here are photos of the modified rotor:

http://www.cybertheque.org/homebrew/...ntennas/rotor/

This rotor is common to a number of makes and models; the controller
that came with it was for the Cornell-Dubilier AR22R, an interrupter
based spring and escapement controller version.

The modifications permit continuous rotation and rely on the
controller to manage limits.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Need sources for pot with planetary drive
 

"Alan Nishioka" wrote in message
ups.com...
On Jul 13, 7:12 am, msg wrote:
Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor
athttp://www.cybertheque.org/homebrew/rcvr/images/antennas/pot.jpg
Resistance = 1K

Interesting. I've never seen a pot like this.

So the turns ratio is determined by the shaft diameter to ball
diameter ratio?
And the wiper arm is connected to the ball carrier?
So this assumes the metal to metal, shaft to ball won't slip, but the
ball will turn in the carrier, causing the carrier to have 1/3 the
rotation of the shaft?

Sorry, this doesn't help you at all...
Alan Nishioka
The ratio, is determined by the shaft diameter, to the internal diameter
of the casing in which the balls sit.
If (for instance), you have a 3mm shaft, and 10mm balls, the casing has to
have an internal diameter of 26mm, and the ratio is 26/3 = 8.66:1. The
drive can be made remarkably good (the same system is used on some micro
focussers for telescopes, which carry significantly more torque than
needed for a pot). Units like the 'Williams optics feathertouch focusser',
use exactly this drive.

Best Wishes

Need sources for pot with planetary drive
 

The ratio, is determined by the shaft diameter, to the internal diameter
of the casing in which the balls sit.
If (for instance), you have a 3mm shaft, and 10mm balls, the casing has to
have an internal diameter of 26mm, and the ratio is 26/3 = 8.66:1. The
drive can be made remarkably good (the same system is used on some micro
focussers for telescopes, which carry significantly more torque than
needed for a pot). Units like the 'Williams optics feathertouch focusser',
use exactly this drive.
=================
Sorry ,but I don't understand the above .
If the shaft has a diameter of 3mm and the balls a diameter of 10mm, the
inner diameter of the casing should be 10 + 10 + 3 equals 23 mm

When the shaft makes 1 revolution the balls will make 3/10 revolution .
When the balls make 1 revolution the casing makes 10/23 revolution .
Hence when the shaft makes 1 revolution the casing will make
3/10 * 10/23 equals 3/23 equals 0.13 revolution , hence reduction factor
is 7.7
Please correct me if I made an error.

Frank GM0CSZ / KN6WH

Need sources for pot with planetary drive
 

Roger Hamlett wrote:
If (for instance), you have a 3mm shaft, and 10mm balls, the casing has to
have an internal diameter of 26mm, and the ratio is 26/3 = 8.66:1.

I could be missing something, but at first glance I read the radius as
the diameter of the 10mm ball (10mm) plus half the diameter of the 3mm
shaft (1.5mm) and get 23mm internal diameter, ratio of 23:3 or 7.66:1.

Just in case this turns out to be a corecktion I've included speling
erors to comply with tradishun.

--
Postulate a group whose intent is to destroy the United States from within
via anarchy and bankruptcy. The actions of the United States Congress are
completely consistent with the actions one would predict from such a group.

Need sources for pot with planetary drive
 

"clifto" wrote in message
...
Roger Hamlett wrote:
If (for instance), you have a 3mm shaft, and 10mm balls, the casing has
to
have an internal diameter of 26mm, and the ratio is 26/3 = 8.66:1.

I could be missing something, but at first glance I read the radius as
the diameter of the 10mm ball (10mm) plus half the diameter of the 3mm
shaft (1.5mm) and get 23mm internal diameter, ratio of 23:3 or 7.66:1.

Just in case this turns out to be a corecktion I've included speling
erors to comply with tradishun.
Yes. Sorry, I just added up the internal diameter wrong....

It is fairly simple to visualise what is happening, if you realise that
the balls are rolling round the internal diameter of the casing, driven by
the small shaft at the centre, and for the assembly of three balls to
complete one complete turn, their surfaces, must travel the internal
diameter of the outer casing. Since the surfaces of the balls are driven
by the internal shaft, you get the ratio from the ratio of these two
diameters.

Best Wishes