Want superior connection, or an ordinary slip ring? The choice is yours. These Frequently Asked Questions explain the benefits of Mercotac's "electrical slip
ring".
Why are Mercotac® rotating connectors superior to slip rings? Mercotac rotating connectors use a unique
design principle unlike the sliding, brush contact of a slip ring.
The connection is made through a pool of liquid metal molecularly
bonded to the contact, which provides a low resistance, stable connection.
When there is rotation the fluid maintains the electrical connection
between the contacts without any wear. The following are among the
many reasons why Mercotac connectors are superior to slip rings. First, unlike a slip ring, Mercotac connectors produce near
zero electrical noise due to their unique design. Second, resistance through the rotating contact is less than
one milliohm, which is much lower than the resistance of a slipring. Third, Mercotac connectors do not degrade
the signal over time, which does happen with slip rings. Fourth, slip rings require maintenance
and Mercotac connectors are maintenance free. Fifth, Mercotac connectors are more compact and cost far less
than slip rings of equal capacity. Read More & See Video Explanation(top)
Are Mercotac® connectors made of durable materials?
Yes. The Mercotac connector
is ruggedly constructed utilizing a sealed ball bearing in a black
anodized aluminum body. The electrical connections are silver plated
brass or copper for low resistance. The white mounting bushing on
both ends of the larger Mercotac connectors is insulating plastic potted with
epoxy. Mercotac connectors are very durable as well as being compact. (top)
Can Mercotac® connectors be used for low voltage signal, data, thermocouple
and strain gauge circuits? Yes. In addition to normal current and voltage uses, Mercotac
connectors are ideally suited to low voltage/low amperage current
and signal transmission. Unlike
standard brush slip rings, Mercotac connectors use liquid metal as the
conductor. This produces an extremely low noise signal transmission
similar to the signal transmitted through a solid wire. This makes Mercotac connectors superior to brush slip
rings for signal and data transmission. The signal quality does not degrade and no maintenance of the
Mercotac connector is required. (top)
How do I select the right Mercotac® connector for my application? The number of conductors, voltage, amperage, and RPM will determine
which model of Mercotac connector needed. First,
decide the number of conductors needed. Next, consult the specification page
to determine if a Coaxial or Modular unit will meet your amperage,
voltage, and RPM requirements. Please note: Even though the larger
Mercotac connectors are rated for 30 amps they work equally well for
signal applications (top)
How are Mercotac® connectors mounted? Mercotac rotating connectors are designed for mounting to the
end of the rotating axis either in a vertical or horizontal attitude. The mounting method depends upon the Mercotac
model. The larger Mercotac
connectors typically are mounted into a hollow shaft or collar on
the end of the rotating device either by the plastic bushing or the
body. The Mercotac connector may be
held in place with a setscrew or a slotted clamp system. The smaller Mercotac connectors plug into the electrical receptacle
and use this both as the mounting and electrical connection. These
receptacles are knurled and designed to be press fitted into a hole
on the end of the rotating device. Eccentricity of the mounting should
be less than .005” TIR (total indicated runnout). The preferable method of mounting the Mercotac connector
is with the black body rotating. Both ends of the Mercotac should not
be rigidly mounted; one end needs to float free. If needed, a floating torque arm may be used to prevent the
stationary end from rotating. Please
note that Mercotac connectors are not designed to support any load. Please see Literature page for
downloadable "Service Instructions" for more details. (top)
Can Mercotac® connectors be used upsidedown? No, Mercotac connectors do have a top and a bottom. An arrow on the side of each unit specifies
the top. A vertical mounting
would position the Mercotac with the arrow pointing up. Mercotac connectors can be mounted at
vertical or any angle between vertical and 90 degrees
horizontal. This allows for
nearly any mounting attitude that would be required. They cannot, however, be mounted with the arrow pointing below
horizontal or upside down. (top)
Can a Mercotac® connector be mounted by the upper bushing? Yes, in special circumstances. In the case of a vertical mounting
(or a mounting somewhat vertical) where the Mercotac connector needs to be mounted
below the rotating device, the Mercotac connector will need to be attached by
the upper bushing into the mounting shaft or collar. In this case the body and lower bushing will be stationary
and free floating. It is very
important that the mounting be straight and centered so there is zero
or minimal lateral motion or wobbling of the body, less than .005
inch TIR is recommended. (top)
What types of wire connections are needed? All the larger Mercotac connectors with tab connections are supplied
with push on disconnects. The
smaller Coaxial Mercotac connectors use plugs available separately
for each model to which customer wires may be soldered. When connecting
wires to the stationary floating end of the Mercotac connector allow
sufficient length as not to pull on the connector. Do not attempt
to solder wires directly to Mercotac terminals.This will damage interior parts causing the connector to fail,
and void the warranty. (top)
Can I solder wires to the Mercotac® connector? No. Attempting to solder wires directly to a Mercotac connector
will overheat and damage the internal parts, cause connector failure,
and void the warranty. Appropriate disconnects are available for Mercotac
connectors and always should be used.(top)
Can standard industrial coax plugs be used on the small Mercotac® Coaxial connectors? No. Because the design of the small Coaxial Mercotac connectors is unique, standard
industry plugs cannot be used. Accessory
plugs are available from Mercotac Inc. (top)
What if I need more than eight conductors? The eight conductor Mercotac model is currently the largest connector
available. There are two options
if more than eight conductors are needed. First, if there is access to both ends of the rotating axis,
two Mercotac connectors could be used. This would increase the amount
of conductors available to a maximum of sixteen. If this is not a
possibility, a Mercotac connector could be combined with a standard slip ring
that has a hole in the center. The Mercotac connector would be used
for the sensitive signal connections and the slipring for any power
connections. (top)
Can Mercotac® connectors be used in damp or corrosive environments? It depends on how damp or corrosive the environment is. While
Mercotac connectors are constructed of corrosion resistant materials
they might not be suitable for all applications depending upon which
corrosives they are exposed to. They also are not suitable to be used
in “wet” environments without protection. Mercotac connectors are
available with a stainless steel ball bearing for use in damp or corrosive
environments. We also recommend the use of the accessory
“Boot Kit” for additional protection with the larger models.
This increases the IP protection rating of the Mercotac to IP51. (top)
Can Mercotac® connectors be used in a vacuum? No. Because Mercotac connectors
contain liquid substances, a vacuum would tend to cause out gassing
and also create internal pressure. This would cause increased rotational
torque and possible failure of the connector. (top)
How long can I expect a Mercotac® connector to last? All Mercotac connectors are warranted for one full year from delivery.The life expectancy depends on several application specific
factors such as vibration, temperature, RPM, mounting eccentricity,
etc. and therefore cannot be accurately predicted for all applications.However, with no vibration and all other specs being within
tolerances, Mercotac connectors typically give years of trouble free
service. Under controlled test conditions they typically last for
more than a billion revolutions. Of course, Mercotac connectors are entirely maintenance free. (top)
How does movement or vibration in my machine affect the Mercotac® connector? Vibration or sudden movement can significantly shorten the life of the Mercotac connector
or even cause failure. Vibration
moves the liquid metal conductor away from the contact area, which
can cause open or shorted channels. If vibration is present in the
application, a vibration isolating mounting should be used to mount
the Mercotac connector. (top)
What is the usual delivery time once an order is placed? All standard models of Mercotac connectors are maintained in stock
in reasonable quantities at our factory in California, USA. Normal
shipping is by UPS Ground, so delivery time is usually one to five
business days depending on distance from southern California. Expedited
shipping can be arranged. (top)
Do you offer any models with a hole in the center? At
this time, we do not offer any models with a pass through hole in
the center. Mercotac connectors are designed to be compact for mounting
at the end of the rotating axis, which makes them less expensive and
more durable.(top)
What part rotates? In
fact, either end can be attached to the rotating device. However,
as described in answer No. 5, it is preferable to mount the Mercotac
so that the body rotates. The body and lower bushing are pressed together
as one unit. The upper bushing (as identified by the "UP"
arrow on the body) is mounted to a ball bearing and turns independently
of the body. Please see the rotating model to the left which shows the body
and lower bushing rotating with the upper bushing stationary. If a
unit needs to be mounted vertically, below the rotating device, then
mounting the Mercotac by the upper bushing with the body floating
stationary is acceptable (also see question No. 7). (top)
Are Mercotac® connectors RoHS compliant? No. Mercotac's connectors contain elemental mercury which is regulated
by the European Union's Restriction of Hazardous Substances (RoHS). However, this directive does not prohibit the import and sale
of industrial parts because it only covers consumer electrical and electronic products. Therefore, Mercotac connectors may still
be legally bought and sold in Europe and elsewhere in the world for non-consumer applications.
(See our explanation page EU Directives.)
(top)
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