Do your slip rings run trouble free for their expected lifecycle? If you answered “no,” you’re not alone. Many engineers who work with rotating machines experience slip ring problems or downtime at some point. The good news is you can easily keep your slip rings running smoothly for the long haul by following just three simple steps.

1. 5245-3 Old Dowd Road, Charlotte NC, 28208 | T: +1 704 705 4711 | F: +1 704 733 9170
WHITE PAPER
https://www.kuebler.com
Maximize Slip Ring Lifecycle
and Performance
Do your slip rings run trouble free for their expected
lifecycle? If you answered “no,” you’re not alone. Many
engineers who work with rotating machines experience slip
ring problems or downtime at some point. The good news
is you can easily keep your slip rings running smoothly for
the long haul by following just three simple steps.
All you need to do is configure, install and maintain the slip
rings properly.
Unfortunately, even experienced engineers sometimes
configure slip rings without paying enough attention to
how the device will be installed on the machine. It turns
out that different mounting orientations call for different slip
ring configurations. And if you get the configuration wrong,
the slip ring may suffer from recurring signal loss problems
and a shortened working life.
Maintenance isn’t always straightforward either. It’s easy to
lay the blame for poor maintenance on end-users, but the
truth is some slip ring designs are inherently difficult to
maintain. What’s more, engineers do not always consider
the actual operating conditions when setting maintenance
expectations, causing them to overstate or understate
service intervals. Bottom line is that slip ring maintenance
starts on the drawing board, not on the factory floor.
In this article, we’ll go over some simple design strategies
that will help you ensure the longest possible life and
lowest possible maintenance for the slip rings used on
packaging and other industrial machines.
Eliminate Configuration Errors
To maximize design flexibility and minimize size, modern
slip rings typically have a modular design. Modularity
allows users to freely combine power and signal channels
to meet their exact application requirements.
Our SR085 slip ring, to take one example of the modular
approach, allows you to configure up to 20 channels,
divided between load and signal any way the application
requires. Each additional module adds just 10 mm to the
slip ring’s base axial length of 64.5 mm.
A few simple design tips will help you
get the most out of your slip rings
Modular Slip Ring Applications
• Packaging machines
• Bottling lines
• Textile machines
• Robotics and automation systems
• Cranes
• Rotary tables

2. 5245-3 Old Dowd Road, Charlotte NC, 28208 | T: +1 704 705 4711 | F: +1 704 733 9170
WHITE PAPER
https://www.kuebler.com
For all the design flexibility of modular slip rings, they can
lead to a common configuration mistake. Oftentimes,
engineers will configure a slip ring without regard for its
mounting orientation.
The reason orientation matters is that the signal channels
are more susceptible to contamination from dust or other
particulate than the load channels. Accumulated dust
can degrade the signal integrity, ultimately shorting the
maintenance intervals and lifecycle of the slip ring.
So it’s important to configure slip rings with the signal
channels above other modules—such as those for power
and labyrinth seals. As long as the signal channels are
on top of the slip ring, gravity will work in your favor
and minimize the amount of dust that falls onto signal
channels.
Inductive Data Transmission
Many slip ring performance issues come down to dust
on the contacts, especially the more sensitive signal
contacts. And configuring the slip ring with the signal
channel above the load channels can only minimize,
not prevent, the inevitable buildup of dust. There is a
new technology, however, that makes dust irrelevant,
at least on the signal channel.
Our newest slip ring, SRI085 uses a contact-less
inductive coupling to transfer signal and data.
Developed for use on high-speed packaging
machines, this new slip ring ensures signal integrity
without any worry about dusty contacts.
Other than its inductive coupling, which does add
some cost, the SRI085 is drop-in replacement for our
SR085 slip ring, which uses oil-free contacts for both
the signal and power channels.
Caption.
Figure 1
Vertical Mounting Position Standing
Vertical Mounting Position Hanging

3. 5245-3 Old Dowd Road, Charlotte NC, 28208 | T: +1 704 705 4711 | F: +1 704 733 9170
WHITE PAPER
https://www.kuebler.com
Keeping the signal channels on top requires an awareness
of the mounting orientation. Vertical hanging and standing
orientations in particular will need different configurations
to ensure that the signal channels remain above the
labyrinth seals (see Figure 1).
With horizontally mounted slip rings, gravity doesn’t help
or hurt the dust situation much. You can locate the signal
and load channels in any order that makes sense for your
application (see Figure 2).
Follow Maintenance Instructions
Another threat to smooth slip
ring operations is a disregard for
recommended maintenance intervals.
Nominally, we recommend the first
maintenance at 50 million revolutions or
after one year of operation, whichever
comes first. Subsequent maintenance
intervals should be scheduled every
additional 100 million revolutions or
yearly.
The maintenance regimen itself is simple:
Just vacuum out any dust that has
accumulated on the slip ring load and
signal contacts. The slip rings used in
most packaging or industrial applications
don’t even require any oil on the
contacts.
While it’s true that engineers have little control over
whether end-users will ultimately adhere to the
recommended maintenance intervals, there are a couple of
key upfront design factors related to maintenance:
Duty cycle. Nominal maintenance intervals may not be
enough if you plan on running a slip ring at high rotational
speeds, at elevated temperatures or in contaminated
environments. These aggressive operating conditions can
lead to signal degradation or even mechanical failures
without an equally aggressive maintenance regimen (see
Figure 3).
Figure 2
Months of Operation
Revolutions,millions
0 2 4 6 8 10 12
0
100
200
300
500
400
100 RPM
300 RPM
400 RPM
800 RPM
600 RPM
Maintenance Intervals vs. Operating Speed
1st
2nd
3rd
4th
5th
Figure 3
Horizontal Mounting Position

4. 5245-3 Old Dowd Road, Charlotte NC, 28208 | T: +1 704 705 4711 | F: +1 704 733 9170
WHITE PAPER
https://www.kuebler.com
Easy access. All slip rings require some routine
maintenance, but not all slip ring designs make
maintenance quick and easy. It’s important to look for
designs that have ready access to the power and signal
contacts without requiring disassembly of the slip ring.
Our designs, for instance, have a removable maintenance
window adjacent to the contacts (see Figure 4).
Slip rings are so common nowadays that engineers tend to
take their performance for granted. And in general, modern
slip rings are reliable enough to tolerate some neglect.
However, if you really want to get the most out of a slip
ring, a little extra attention to mounting orientation and
ease-of-maintenance will go a long way.
Slip Ring Design Principles
High-performance seals. Kuebler Safety-Trans™ design features an integrated labyrinth seal that separates the
respective cavities for the power and signal channels. The labyrinth seal serves two roles—dust protection and
electrical isolation between channels.
Advanced contact materials. Optimized materials ensure reliable signal and data transmission in different
applications. For example, our silver alloy brushes and precious-metal contact surfaces have very low resistance of
less than 0.1 Ohm, making it possible to transmit low voltage, low current signals.
Mechanically robust. Construction of the springs
ensures power and signal transmission even with heavy
vibration loads. Pick-off springs for load currents are
made from copper graphite, which is highly abrasion
resistant. The springs for signal currents are made from a
resilient gold and platinum alloy with 50% gold content.
Easy Maintenance. All contacts are accessible through
a removable maintenance window for easy cleaning.
Brushes can also be accessed and replaced individually
as needed.
Figure 4