Through-bore slip rings
ER Series Through Bore Slip Ring
Through-bore slip rings with a hollow centre so shafts, pipes or cables can pass through, carrying power, signal and fieldbus data. Standard bores run from 12.7 mm to 100 mm and custom bores are offered.
Key specifications
| Circuits (max) | 24 |
|---|---|
| Current per circuit (max) | 15 A |
| Voltage (max) | 380 V |
| Speed (max) | 300 rpm |
| Bore | 12.7–100 mm |
| Ingress protection | IP51 standard, up to IP68 |
| Temperature | -20–60 °C |
| Data / bus | Ethernet, USB, HDMI, SDI, CANbus, Profibus, audio |
| Rated life (revolutions) | 20,000,000 |
| Bandwidth | up to 1G (page) |
Series ranges as published; individual models vary. The full datasheet, drawings and CAD models are available on request.
Options
- custom bore 3-5000 mm
- up to 300 circuits
- up to 2000A total current
- anti-vibration / anti-shock
- corrosion resistant
- waterproofing to IP68
- crosstalk prevention
- mixed signal types in one unit
Typical applications
What a through-bore slip ring is
A through-bore slip ring is a rotary electrical joint built around a hollow centre, so a drive shaft, pneumatic or hydraulic line, fibre or cable bundle can pass straight through it. The rings are mounted on an insulated sleeve that fits over or around the machine shaft, and the brush blocks sit outside them in a stationary housing. Power, signal and data circuits are combined in one unit, while the bore keeps the rotation axis available for mechanics or services. Bore sizes range from a few millimetres to hundreds of millimetres.
When engineers choose a through-bore slip ring
Engineers choose a through-bore design when the axis of rotation is already occupied, typically by a shaft, a rotary union or a cable that must stay continuous. It is the standard choice for indexing tables, wrapping machines and turntables built around a central column. The trade-off is that larger rings mean higher surface speed, more brush wear and more drag torque at the same rpm, and the unit is bigger than a capsule. Where axial length is the constraint rather than diameter, a pancake design may suit better.
How to specify the ER Series Through Bore Slip Ring
Send these with your enquiry and an engineer can confirm the right ER Series Through Bore Slip Ring variant:
- Bore diameter and shaft tolerance (mm)
- Outer diameter and length limits (mm)
- Circuit count and current per circuit (A)
- Working voltage and any high-voltage isolation (V)
- Speed, continuous and peak (rpm)
- Data or bus protocols to pass, such as Ethernet, CAN or PROFINET
- Sealing (IP code), temperature (°C) and mounting method
Common mistakes to avoid
- Sizing the bore to the shaft only, with no allowance for a rotary union or cables that must also pass
- Mounting the rotor hard on a shaft with radial runout and a separate stator fixing, so the unit is forced to align two axes
- Forgetting that surface speed rises with diameter, so the rated rpm is lower for larger bores
- Not stating which circuits need screening or twisted pairs for encoder and fieldbus signals
ER Series Through Bore Slip Ring: frequently asked questions
What is the ER Series Through Bore Slip Ring?
Through-bore slip rings with a hollow centre so shafts, pipes or cables can pass through, carrying power, signal and fieldbus data. Standard bores run from 12.7 mm to 100 mm and custom bores are offered. Published series figures include circuits 24, current per circuit 15 A, voltage 380 V, speed 300 rpm. It is available through our supply network, and our engineers can confirm the right variant for your application.
Who makes the ER Series Through Bore Slip Ring?
The ER Series Through Bore Slip Ring is part of a range available through our supply network. Send us your requirement for pricing, lead time, datasheets and CAD.
What is the circuits of the ER Series Through Bore Slip Ring?
The published series maximum circuits is 24. Individual models and sizes in the ER Series Through Bore Slip Ring range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
How do I choose the bore size for a through-bore slip ring?
Start with the shaft diameter and its tolerance, then add anything else that must pass through the centre, such as hoses, a rotary union stem or a fibre. Allow clearance for assembly and for the insulating sleeve. Larger bores raise surface speed, cost and drag torque, so pick the smallest bore that genuinely clears what has to pass through.
Can a through-bore slip ring carry Ethernet as well as power?
Yes. Many through-bore units combine power rings with signal rings designed for industrial Ethernet, using controlled impedance, twisted-pair routing and screening between groups. State the protocol and speed, typically 100 Mbit/s or gigabit, so the supplier can allocate suitable rings and keep them away from motor power. For very high data rates, a contactless or fibre channel may be added.
Further reading: How to select a slip ring · Ethernet through slip rings · Slip rings
Often compared with
Engineers specifying this series often compare it with:
Spec builder
Configure ER Series Through Bore Slip Ring
Select every part you need, answer the questions an applications engineer would ask, and see your summary before we ask for any details.
- 1Products
- 2Performance
- 3Environment
- 4Volumes
- 5Your spec
Engineer support
Need ER Series Through Bore Slip Ring or a complete system around it?
Tell us what you need, whether it is this part, an equivalent or a complete axis built around it. An engineer will review your requirements and reply, normally within one working day.
- Reviewed by an engineer, not an autoresponder
- Like-for-like and better-fit alternatives
- Standard, modified and custom options
Prefer to configure it? Use the spec builder.