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WHAT IS A SLIP RING?

• 360 degrees continuous rotating & get electricity passed.

Slip ring is very important component and parts that can solve the 360 degrees continuous rotating , and get electricity to a continuously rotating part of my assembly, rotate without limits. Working style of slip ring is similar as bearing, it usually rotates at inner cycle and keep non-rotating at outer cycle. Inner cycle with wires inlet and outer cycle with wires out, all wires have one-to-one correspondence for continuous conduction,See figure as what is a slip ring as below:



slip ring technolgy
Figure 1

• Make products more beautiful and compact appearance.

For a automatic device, the slip ring is a very key parts. It is the core component that connects the rotating part and static part. The slip ring can solve all issues on site on many occasions. The slip ring can make the move freely and make the device work more efficiently. Besides high science and technology feeling, moreover, it achieves more beautiful and compact appearance.

• Consists of mechanical part and electrical part

A slip ring consists of mechanical part and electrical part. Mechanical part includes the dimension, weight and protection grade of the slip ring. While the electrical part is much complicated, for it includes power and various signals, such as shielding signal, high-frequency signal, bus signal and so on. When choosing a slip ring, electrical engineer and mechanical engineer need to both be involved and decide.

Mechanical part of slip ring

Dimensions of the slip ring is essential important to automatic device. The slip ring not only needs to keep compact structure but also meet the needs of the device, also for it’s electrical performance.

Electrical part of slip ring

Electrical parameter, power , big current and sensitive signals are fields with difficulties and challenges, which includes big power, especially for those slip rings with big currect above 500A and various high-frequency sensitive signals.

• Needs of slip rings customized

A lot of times, the diversity of the needs of slip rings should be customized on customers’ request, such as height/length limitation or OD(outer diameter) limitation, etc.

As to the slip ring contact, double contact is more reliable than the single contact.

Current technology has realized the same ring with 12 contacts. To the circuit of slip ring, width and size are very important to signal transmission.


contact & rings
Figure2(contact & rings )

How to Select a slip ring?

Slip ring is a core parts of the device. Choosing a suitable product has great impact on lead time, cost and performance.


rings and wires of slip ring
Firgue 3(rings and wires of slip ring)

Before choosing a slip ring, some parameters must be provided as below:

  • • Total wires
  • • Wires for power
  • • Wires for signal
  • • Shielding for signal wires?
  • • Size Limitations
  • • Max OD,Max length?
  • • Axis mounting, flange mounting, End face mounting
  • • Require through bore? how much is the bore size?
  • • Lead wire exit?(2 sides and one side)
  • • Lead length(default is 300mm)
  • • Working condition
  • • Revolution per minute
  • • Max rotating speed?
  • • How many working hours per day
  • • Expected life(revolution and time)
  • • Working teperature
  • • Working humidity
  • • Requirement for protection grade
  • • Extra Requirements inside slip rings
  • • Encoder
  • • Connectors
  • • Fluid rotary unions
  • • Coax rotary unions
  • • Fiber optic rotary joints

Then, we can build exact slip rings for you in 15 days.

What’s the material of the slip ring?

The material of the slip ring can be customized on different request, including housing material and internal contact material.

Housing material of slip ring

For housing material, generally, the material of plastic insulation are adopted. Certainly, it’s possible to demand the flame retardant function and meet the needs of UL grade. For this material, it has the advantage of light weight, lower cost and fast delivery, but it also has the disadvantages, such as poor load-bearing and not survive high temperatures.

slip ring inside material
Figure 4(slip ring inside material)

In general, industrial products adopt the aluminum housing. This aluminum housing has advantage of heat eliminable and  strong bearing capability. Moreover, light weight  can protect precision part well, also no rust occurred. Because of this, the cost will be higher, so it will have some limits when used in large scale and in large volumes.

Usually, military level products adopt stainless steel. The cost is not the main factor of consideration, while solidness and durability are the key factor now. Stainless steel material, with better reliability and bearing, can be perfect to protect the slip ring interiority.

Contact material inside slip ring

Precious metal material is one of ordinary materials. But because of the different ingredients,

the performance of the parts can vary widely.

For big power and big current, the contacts mainly adopt the most conductive.silver as material, then plate the gold at housing. For contacts of sensitive signals, it possibly adopts high tenor in gold, including various elements, such as gold, silver, copper and so on.

Contact material need to satisfy good conductivity. For those materials with excellent wearability and high hardness, it means that they have good conductivity. It’s very important to choose the contact material for slip rings.

How does a slip ring work?

A slip ring consists of two parts, the one is stator part, the other is rotor part. The stator part often fixes the contact and the rotor part often put the ring. The relative rotation of two parts can ensure alignment by two horizontal bearings.
Two working styles of slip rings

1)Cylinder working type of slip ring

The ring and the ring is arranged along the axial direction. For this slip ring type, more rings with longer axial length, but each ring spinning speed is the same, which can well guarantee the working life of slip rings. Structure chart is as follows.

Cylinder Style of slip ring working
Figure7 – Cylinder Style of slip ring working

2)Disc working type of slip ring

The ring and the ring is arranged along the radial direction. For this slip ring type, more rings with bigger OD(outer diameter), but with small overall height, which can be well applied to those devices that have limitations on height or length. Structure chart is as follows

Disc Style of slip ring working
Figure8 (Disc Style of slip ring working)

What is slip ring used for?

The slip ring will come in handy when transferring the media (electric, gas, fluid, light) from one rotating equipment to another fixed equipment or from one fixed equipment to another rotating equipment. In the meantime, it will solve the wire wrapping and wire broken while using the slip ring. So the slip ring is a bridge used for connecting rotating equipment and fixed equipment.

How many types of slip rings?

Slip ring classified by conductive property

Slip ring can be classified according to conductive property: electric slip ring, pneumatic/hydraulic electric slip ring, fiber optic slip ring, pneumatic/hydraulic slip ring and photoelectrical slip ring.

Slip ring classified by industry application

Slip ring can be classified according to industry application: high-speed electric slip ring, high temperature conductive slip ring, big OD (outer diameter) slip ring, anti-explosion slip ring, strain gage signal slip ring, military level slip ring, reel slip ring, single crystal furnace slip ring, crane slip ring, revolving door slip ring, rotary table slip ring, etc.

Slip ring classified by outline

Slip ring can be classified according to standard electric slip ring: through bore slip ring, compact through bore slip ring, wind turbine slip ring, high current slip ring, servo encode slip ring, waterproof/underwater slip ring, 1000M Ethernet slip ring, industry field-bus slip ring, thermocouple slip ring, miniature pneumatic slip ring, standard pneumatic/pneumatic electric slip ring, pneumatic/hydraulic electric combination slip ring, fiber optic slip ring, high frequency/waveguide-coaxial rotary joint, 1080/1920 high-definition slip ring, miniature through bore slip ring, capsule slip ring, miniature capsule slip ring, super-miniature capsule slip ring, flat pancake slip ring, separate slip ring, USB slip ring, mercury slip ring and winch slip ring, etc, see all types slip rings picture as below:

All types of slip rings
All types of slip rings
All types of slip rings
Figure8 (All types of slip rings)

Benefits and advantages of slip ring.

Situation without slip rings

Rotating equipment doesn’t adopt a slip ring. It will easily cause wire wrapping and even wire broken while equipment is rotating. And it has not beautiful appearance.

Situation with slip rings

Rotating equipment adopts a slip ring. It successfully avoids wire wrapping and wire broken. It not only has more stable signal transmitting but also has beautiful appearance.

How to make a slip ring?

Step 1: familiar with principle

Before making a slip ring, the operating principles of slip ring must be well mastered.

Step 2: selecting material as required

Suitable materials are needed to select according to applications and specific parameters, such as current, voltage, signal frequency, connecting media, operating environment, working life, rotating speed and torque, etc.

Step 3: industrial design

Do the best industrial design according to mounting way, assembling process, electrical disturbance and aesthetics。

Step 4: process design

According to industrial design, the most suitable assembly technology can reduce the assembling difficulty and improve the assembly efficiency.

Step 5: assembly manufacturing

Strictly based on the engineering drawing, opening the mould, assembling products, reducing reject ratio by human error; Definitely, experienced and well-qualified assembly operator plays an essential role in improving the product quality.

Step 6: quality testing

Testing products’ function and quality should be in strict accordance with parameters. For those products not up to standard should be rebuilt. A good quality testing reflects the spirit of the craftsman of manufacturer and also reflects manufacturer’s strong support and protecting for high-end brand products.

How to maintain the slip ring?

Slip ring maintenance is very important

In order to improve the working life of slip ring and avoid long-time machine halt and repair, regular slip ring maintenance is very essential and important.

Slip ring maintenance schemes

Maintenance schemes are provided according to slip ring type by manufacturers. Generally, getting the slip ring an annual check-up and providing the slip ring maintenance every 3-5 years as needed, which can avoid some breakdown.

Brushes & rings maintenance

Brushes and rings are often needed to be maintained for long-time rotating. With the increasing of rotating number, the wear also increases, which achieves the number of revolutions for maintenance. Obviously, the maintenance time is not only related to rotating number but also internal environment where the slip ring is operating.

Application industries and cases of slip rings

With the advancement and development of industry 4.0, the use of slip rings is becoming increasingly wider and deeper. Also the demanding of slip rings is increasing year by year.

Application industries

Application cases

Security and protection

High-speed track ball,UAV table, etc.

Industry field

Robotic arm、robot、winding machine、filling machine、working turntable、engineering machinery、packaging machinery、cable reel、centrifugal machine、transmission system、automatic welding machine、aerial work platform, etc.

Wind power generation

Variable wind plasma generating control slip ring.

Medical facility

Operating astral lamp,CT equipment, etc.

Military field

Radar,target-shooting machine, etc.

Special working condition

Smelting equipment、mining equiment、special type of vehicle、special type of ship.

Entertainment

Amusement equipment、arcade game、high definition camera、optical transceiver communication, etc.

Others

Revolution door、car wash Equipment、exhibition and display etc.


Slip ring FAQ

What are the differences between slip ring and brush?

Brush is a main part of the slip ring. Brush is a lump and installation parts consisting of graphite, precious metal or carbon material, which connects with the system outside of the rotating parts. When operating, rings with rotating can continuously contact with these brushes. Finally, it can realize the power and data signal transmission.

How to choose a suitable slip ring to adapt your own system?

Slip ring is sophisticated mechanical and electrical products. Before choosing, some factors should be taken into consideration, such as rotating speed, current, voltage, signal type, size and environment and so on. After comprehensive evaluation, a suitable slip ring can be chosen.

Which part of the assembly stays stationary and which part rotates?

There are two distinct parts of a slip ring. Functionally it makes no difference whether the core (center stack) or the brushes (mounting base and housing) rotate. It is all dependent on how the assembly is mounted and installed on your machine or equipment.

Can I transmit data signals through your slip ring such as DeviceNet, Profibus, Can Bus, Internet signal, High speed date signal?

All power and signal wires above 24 volts can be used with standard wires. But for Internet and High speed date signal, it depend on the frequency of signal, we have special High speed date model to pass these signal.

which kinds of technical data should be provided when choosing slip rings?

When selecting slip rings, the following important performance specification should be taken into consideration:
1. Operating speed rpm
2.Circuits, signal rings (Circuit, ring and way are all synonymous. If there is a return path or ground then it is a separate circuit. In some slip rings a circuit can be used either way and is counted only once.)
3. Maximum voltage and current for the power circuits and signal circuits.
4. Type of signal (very important)
5. Operating temperature
6. IP grade ( sealing requirements)

Why does slip ring rotate unsmoothly :

The reasons for causing such problems generally are haven`t chosen anti-vibration type when customers choosing the sealed slip ring, but with the environment there are strong vibrations. Resulting in damage of thin bearings within the slip ring , plastic spindle rupture, etc.

Why are our slip rings burn out?

Maximum current slip ring allowed is a current value of safe operation, which depends on the cross-sectional area of the conductive ring, the contact area of the brush, the pressure of the brush and contact surface, rotational speed and other integrated factors. If exceeds this value, slip rings will likely generate heat, seriously contact surface will light a fire , and even welding points will be formed between the brush and conductive ring. Although we will consider certain safety factor in the design phase of conductive slip ring, still recommends that customer offers maximum current based on the actual to the slip ring manufacturer.

Click and go moflon slip ring products center, and select more slip rings.

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