Servo motors on rotary table, no slip rings!
Servo motors on rotary table, no slip rings!
(OP)
Hopefully I have the right forum!
I have an application where I need to have a servo motor and some I/O mounted on a rotary weld table, but we don't want to use slip rings. I realize I will need to for motor power and for the welding ground cable, but I don't want to run communication signals through a slip ring. This would include the servo encoder/resolver, and the external I/O.
Many companies make remote sensor blocks which can send power through an air gap, but they all need to be centered on the axis of rotation, as do the slip rings.
So, does anyone have any experience with these kind of problems? The last similar job we manufactured with cable drums on the rotary axis and set up positive stops to prevent cable stretching. We would like to avoid this if possible, as even flex cable has a finite lifespan, and it is very difficult to replace.
I have an application where I need to have a servo motor and some I/O mounted on a rotary weld table, but we don't want to use slip rings. I realize I will need to for motor power and for the welding ground cable, but I don't want to run communication signals through a slip ring. This would include the servo encoder/resolver, and the external I/O.
Many companies make remote sensor blocks which can send power through an air gap, but they all need to be centered on the axis of rotation, as do the slip rings.
So, does anyone have any experience with these kind of problems? The last similar job we manufactured with cable drums on the rotary axis and set up positive stops to prevent cable stretching. We would like to avoid this if possible, as even flex cable has a finite lifespan, and it is very difficult to replace.





RE: Servo motors on rotary table, no slip rings!
An alternative might be to achieve signal coupling via wire coils centered on the table axis with Hall Effect sensors positioned in proximity to each coil in order to sense the magnetic field generated by each coil. This would of course require coils fixed to both the table and a stationary frame. Although this might be done using pure inductive coupling (coil to coil) the coil to Hall Effect sensor method would be interference free and far more reliable.
Hope this gives you food for thought.
Bruce
RE: Servo motors on rotary table, no slip rings!
You may find some information here:
http://www.isea.rwth-aachen.de/Ww/english/
Search for Publications on that topic by T. Kalker, A. Eßer and A. Nagel
Later some Japanese servo-drive manufacturer, unfortunately I do not remember the name, continued to work on that topic.
RE: Servo motors on rotary table, no slip rings!
RE: Servo motors on rotary table, no slip rings!
The deeper I get into this project, the more I am swayed to using slip rings. I have contacted a company that will custom-make a non-metalic slip ring that will combine all the signals I need in this application.
Any other hints?
RE: Servo motors on rotary table, no slip rings!
RE: Servo motors on rotary table, no slip rings!
On these, the motion was only 180 degrees fwd and back. So the cables were just high-flex and came through the center to the motors and stages mounted on the system.
Maybe do an 3-ph AC slip ring to put power to the table top then mount the control pannel there for the drives & motors.
Cameron Anderson
Sales & Applications Engineer
www.aerotech.com
"Dedicated to the Science of Motion"
RE: Servo motors on rotary table, no slip rings!
Does anyone know any places to get slip rings?
RE: Servo motors on rotary table, no slip rings!