Fibre optic rotary joints - slip rings for combined power, signal and data transmission
Compact slip rings with 1-8 optical fibres
- Number of rings: 2-80
- Nominal current: 5-10A per ring
- Max. Working voltage: 440VAC/DC
- Voltage withstand: ≥500V @50Hz
- Electrical noise: max 10mΩ
- Isolation resistance:
≥1000 MΩ @ 500 VDC
- 1-8 optical fibres
- Rotation speed:
- Contact material:
- Cable length: freely definable,
Standard: 300mm (rotor/stator)
- Casing material: aluminium
- Protection class: IP51 (higher on request)
- Working temperature: -30°C – +80°C
Fibre optic slip ring
Fibre optic slip ring for maximum data rates. Light waves are the fastest and lowest-loss form of data transmission available. The international designation for the fibre optic slip ring is “FORJ”. This means “Fiber Optic Rotary Joints”. In addition, fibre optic cables have numerous other advantages.
These include the following properties:
- Reliable signal transmission without interference
- Insensitive to electromagnetic interference
- No earthing or galvanic isolation necessary
- Totally harmless
- Extremely high security against eavesdropping
- Very high ranges without intermediate amplification
- Very high transmission rates
Optical fibres can be laid in bundles. Any signal introduced is reliably passed through without affecting the neighbouring strands. They can also be laid next to power lines without any problems. Optical fibres are insensitive to magnetic fields of any kind. Since they are based on a different physical principle than power cables, fibre optic cables require neither earthing nor galvanic isolation. They do not conduct electricity and cannot cause fires. They are practically insensitive to unwanted eavesdroppers.
One disadvantage of fibre optic cables is their complex assembly. Interruptions quickly reduce the transmission rate and speed of these data carriers. Until now, this was especially true for complicated transitions, such as from a stationary to a rotating conductor. We have solved these problems with our new fibre optic slip ring.
Structure of the fibre optic slip ring
Encapsulated miniature slip rings consist of a rotating and a stationary part. A series of contact rings are attached to the rotor, which are insulated from each other. To the inside, the contact rings are connected with an insulated cable, which is led out of the slip ring to the front. Signal cables also run in at the stator part, which end in sliding contacts. Incoming and outgoing cables always have identical colours, so that confusion-free assignment during installation is guaranteed. The sliding contacts touch the contact rings of the rotor inside the slip ring. The contacts are reinforced by a spring, which ensures reliable signal transmission within the technical parameters of the component. No matter at what angle the rotor is turned in relation to the stator, the transmission of signal or power current is always maintained in this way. The encapsulation serves to shield the sensitive inner workings of the slip rings from external interference. All you have to pay attention to during installation is that the slip ring with the rotating component is positioned exactly in one axis. For this purpose, robust flanges with pre-drilled guides for the retaining screws are often attached to the encapsulated miniature slip rings.
Use of the fibre optic slip ring
Although we have designed our fibre optic slip ring for a rotation speed of 1000 and more revolutions per minute, this application is rather rare. The fibre optic slip ring has its strength in passing important signals in areas where current-carrying conductors are a potential hazard. This is why the fibre optic slip ring is particularly popular in avionics and nautical applications.
It reliably transmits signals without picking up interference or becoming a hazard itself due to obsolescence. Nevertheless, every rotarX fibre optic slip ring is permanently encapsulated. The housing complies with protection class IP 51. Higher protection classes are available on request. The robust aluminium housing makes the fibre optic slip ring sufficiently insensitive to light impacts, corrosion or aggressive environments. This means that the fibre optic slip ring can be used for many years under extreme conditions without hesitation.
Advantages of the fibre optic slip ring
The fibre optic slip ring convinces with its high versatility and reliability. Above all, the throughput of the light signals is guaranteed by this slip ring with consistent precision. With its robust housing, it is adequately protected against most expected adversities.
Inside, gold-gold contacts ensure consistent reliability in the transmission of signal and power current, even during electrical feed-through. In summary, the fibre optic slip ring offers the following advantages:
- Ideal rotary feed-through element for fibre optic cables
- Minimal signal interference at the transition
- Robust aluminium housing in IP51 protection class
- High rotation speed
- Wide temperature range
- Compact design
Product features of the fibre optic slip ring
The fibre optic slip ring is available with a choice of up to 72 additional electrical feedthroughs in addition to the fibre optic feedthroughs. Each ring can conduct a current of 5-10 amperes. Each feedthrough can be loaded with 440 volts, regardless of whether it is DC or AC voltage. The dielectric strength is just under 500 volts at 50 hertz. The electrical noise is limited to a maximum of 10 milliohms. The insulation resistance is just under 1000 megohms at 500 volts DC.
The fibre optic slip ring has a maximum of eight passages for fibre optics. The rotation speed is a maximum of 1000 revolutions per minute. The temperature range is from – 30 °C to a maximum of +80°C.
Installation of the fibre optic slip rings
We supply each fibre optic slip ring with a cable length of 300 millimetres, unless we receive other specifications. For electrical feedthroughs, short conductors are quite problem-free. They can be easily extended by soldering or plug-in contacts. With fibre optic cables, however, the extension is always a big challenge. The signal line is already interrupted in the slip ring itself.
Therefore, we recommend ordering the fibre optic cables at the input as well as at the output specifically for the installation situation. We will be happy to assemble your fibre-optic slip rings exactly the way they are best suited to your installation situation. This includes cutting the fibre optic cables to any length with millimetre precision.
This allows you to lay a single line from the signal source to the control unit. The only interruption along the signal path is then only the rotary joint. With this minimal intervention in the signal line, the transmission rate and speed are hardly affected and you can enjoy all the advantages of this safe and reliable technology.
Use of the fibre optic slip ring
The fibre optic slip ring is used wherever fibre optic signals need to be combined with a rotary feedthrough. The low weight, high transmission power and inherent safety of fibre optic cables make them very popular as signal carriers in sensitive and critical areas. These include the following areas of application:
- Aircraft construction
- Drone construction
- Surveillance technology
- Vehicle construction
In all areas, fibre optic cables and their additional components convince with low weight, excellent technical fire protection, eavesdropping security, high data rates and long transmission paths without additional amplifiers. Especially in shipbuilding and aircraft construction, the increased use of fibre optic cables and their matching slip rings provides a significant plus in operational safety.
Your way to the perfect fibre optic slip ring
We have a wide range of fibre optic slip rings in our programme. However, if our offer does not optimally fit your challenges, please give us a call. If desired, we will manufacture the fibre optic slip ring you need. If your request cannot be clarified over the phone, please send us an e-mail. Please illustrate your challenge with a drawing and photographs. This will give our customer service team the best possible picture of your problem. After a thorough analysis of your technical challenge, we will present you with a selection of possible solutions. In a joint discussion, we will then find the perfect fibre optic slip ring for you. We can supply you with any quantity from 1 piece. Trust us and our experience with slip rings of all kinds. We are the specialists who solve your problems. Let us inspire you.
Practical slip ring solutions for your application
Product catalogue for all slip rings
Find out about the different slip rings in our current overview. Transmission technology for complex industrial and safety-relevant applications form the core of our product range. All products can be individually adapted to the applications in order to offer you added value. Premium engineering - that is our claim for every single product we manufacture. We would like to convince you of this.
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