Large-diameter slip rings
Stemmann-Technik LP series bako large-diameter slip ring
Modular contact-plate slip ring system from 46 to 950 mm, with free bores up to 950 mm, flat or concentric low-height designs, high-current and medium-voltage (up to 30 kV) options, encoder fixtures and media distributors.
Key specifications
| Voltage (max) | 30,000 V |
|---|---|
| Bore (max) | 950 mm |
| Outer diameter | 46–950 mm |
| Ingress protection | IP54 to IP65 (LP60) |
| Voltage note | medium-voltage components up to 30 kV offered as an option |
| Od note | sizes 46–950 mm as published |
Summarised in our own words from Wabtec Corporation's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
Current per ring, speed and temperature not published.
Specify Motion is not affiliated with Wabtec Corporation. Stemmann-Technik and LP series bako are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a Stemmann-Technik part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These series from our supply network is the closest match on published figures.
Large through-hole slip rings for heavy outdoor plant, with through holes quoted up to 1000 mm and long service life.
| Published maximum | LP series bako | Large Size Slip Ring |
|---|---|---|
| Circuits | — | 35 |
| Current per circuit | — | 50 A |
| Voltage | 30,000 V | 500 V |
| Bore | 950 mm | 1,000 mm meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
What a large-diameter slip ring is
A large-diameter slip ring is a rotary joint with a bore or ring diameter typically of several hundred millimetres up to a few metres, built for very large rotating structures. The rings are often fabricated in segments or machined as drums or platters, with brush blocks mounted around the stationary frame. Because the structure is large, they are usually designed to match the customer's machine and may integrate power, signal, data, fibre or contactless channels and media passages in one assembly.
When engineers choose a large-diameter slip ring
Choose a large-diameter design when the rotating structure has a big central opening, such as CT gantries, large turntables, radar pedestals, cranes and slewing platforms, or when cabling and services must pass through a wide bore. The trade-offs are cost, lead time and high surface speed even at modest rpm, which limits speed and raises brush wear. Mechanical runout of the machine becomes significant at this scale, so the slip ring is usually designed alongside the structure rather than chosen from a catalogue.
How to specify the Stemmann-Technik LP series bako
Send these with your enquiry and an engineer can confirm the right LP series bako variant or an equivalent:
- Bore and outer diameter limits (mm)
- Speed and surface speed (rpm, m/s)
- Power circuits, current and voltage (A, V)
- Data rates and channels, including contactless or fibre
- Structure runout and flatness at the mounting faces (mm)
- Environment: outdoor exposure, IP code and temperature (°C)
- Segmentation for installation and maintenance access
Common mistakes to avoid
- Specifying late, when the structure leaves too little room or too much runout for the slip ring
- Using the catalogue rpm without checking surface speed at the actual diameter
- Not planning how the ring will be lifted, installed and serviced in place
- Leaving out data rate growth, so the channel count is outgrown within the machine's life
Stemmann-Technik LP series bako: frequently asked questions
What is the Stemmann-Technik LP series bako?
Modular contact-plate slip ring system from 46 to 950 mm, with free bores up to 950 mm, flat or concentric low-height designs, high-current and medium-voltage (up to 30 kV) options, encoder fixtures and media distributors. Published series figures include voltage 30,000 V, bore 950 mm, outer diameter 46 mm, outer diameter 950 mm. It is made by Wabtec Corporation; Specify Motion can help source it or propose an equivalent.
Who makes the Stemmann-Technik LP series bako?
The Stemmann-Technik LP series bako is made by Stemmann-Technik (Wabtec Corporation) and is listed here for engineers comparing options. Specify Motion is not affiliated with Wabtec Corporation; brand names are used only to identify the product.
What is the voltage of the Stemmann-Technik LP series bako?
The published series maximum voltage is 30,000 V. Individual models and sizes in the LP series bako 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.
Is there an alternative to the Stemmann-Technik LP series bako?
Yes. On published figures, Large Size Slip Ring is the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
Why do large slip rings have lower speed ratings?
Surface speed is diameter multiplied by rotational speed, so a ring a metre across turning at 60 rpm already runs faster at the contact than a small capsule at a thousand rpm. Brush wear, heat and contact bounce all rise with surface speed. Large-diameter designs manage this with brush materials, contact force and runout control, but their rpm ratings are typically far lower.
How is high-speed data passed through a large-diameter slip ring?
Contact rings work for slower networks, but for very high data rates, such as CT image data, large rings often use contactless capacitive, inductive or optical transmission around the circumference. A fibre optic rotary joint can also be placed on the axis if the centre is accessible. State the data rate and latency requirements early, as they shape the whole design.
Further reading: How to select a slip ring · How to select a fibre optic rotary joint · Slip rings
Other large-diameter slip rings series
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