Slip rings
Stemmann-Technik FP series (FPKK, FPKR) slip ring
Modular carbon/brass slip ring assemblies for rugged environments: FPKK units in glass-fibre reinforced plastic carry 25, 50 or 100 A per ring with 500 V AC insulation and up to PE + 17 poles, and the FPKR uses a steel housing.
Key specifications
| Circuits (max) | 18 |
|---|---|
| Current per circuit (max) | 100 A |
| Voltage (max) | 500 V |
| Ingress protection | IP65 (intro) / IP66 (table) |
| Voltage note | 500 V AC insulation rating |
| Circuits note | PE + 17 poles on FPKK 54-25; LPKK contact-plate version up to 60 paths |
| Technology | brass rings, two bronze carbon brushes per ring |
| Options | thermostatic heater |
Summarised in our own words from Wabtec Corporation's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1 · Source 2
Notes on this data
Page is inconsistent on IP (65 vs 66). Speed and temperature not published.
Specify Motion is not affiliated with Wabtec Corporation. Stemmann-Technik and FP series (FPKK, FPKR) 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 2 series from our supply network are the closest match on published figures.
High-circuit-count slip rings that carry hundreds of mixed power, digital, analogue, fibre and RF channels in one unit.
| Published maximum | FP series (FPKK, FPKR) | Multi-channel Slip Ring |
|---|---|---|
| Circuits | 18 | 500 meets or exceeds |
| Current per circuit | 100 A | 30 A |
| Speed | — | 480 rpm |
| Voltage | 500 V | 700 V meets or exceeds |
| Bore | — | 40 mm |
Slip rings using heat-resistant materials for extreme temperatures from -55°C to +250°C, such as hot rollers and heating plant.
| Published maximum | FP series (FPKK, FPKR) | High & Low Temperature Slip Ring |
|---|---|---|
| Circuits | 18 | 48 meets or exceeds |
| Current per circuit | 100 A | 50 A |
| Voltage | 500 V | 500 V meets or exceeds |
| Bore | — | 88 mm |
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 slip ring is
This group covers slip rings that do not fit a single standard format, including modular and split designs, contactless capacitive or optical data rings, temperature-rated units, quick-connect terminal designs, very high circuit counts and application-specific assemblies for wind turbines or packaging. All solve the same problem: transferring power, signals or data between stationary and rotating parts of a machine. What differs is the construction, which may be a split housing, a modular stack, a non-contact data path or a special material set.
When engineers choose a slip ring
Engineers look at these designs when a standard capsule, through-bore or pancake unit does not fit the job. Split rings suit retrofits onto existing shafts. Contactless data rings suit high data rates or long life without wear. Modular units allow circuit counts to change between machine variants. The trade-offs are cost, availability and, for custom designs, longer lead times and qualification. Match the construction to the real constraint, whether that is installation, data, temperature or circuit count.
How to specify the Stemmann-Technik FP series (FPKK, FPKR)
Send these with your enquiry and an engineer can confirm the right FP series (FPKK, FPKR) variant or an equivalent:
- What makes the application non-standard: installation, data, temperature, circuit count or format
- Circuits, current and voltage (A, V)
- Data protocols and rates
- Speed (rpm) and expected life (revolutions)
- Bore, envelope and mounting (mm)
- Temperature range (°C) and IP code
- Terminations, such as flying leads, connectors or quick-connect tabs
Common mistakes to avoid
- Choosing a special design when a standard type with minor changes would do
- Not stating the actual constraint, so the supplier offers the wrong format
- Assuming contactless data channels also carry power
- Underestimating lead time for custom or modular builds
Stemmann-Technik FP series (FPKK, FPKR): frequently asked questions
What is the Stemmann-Technik FP series (FPKK, FPKR)?
Modular carbon/brass slip ring assemblies for rugged environments: FPKK units in glass-fibre reinforced plastic carry 25, 50 or 100 A per ring with 500 V AC insulation and up to PE + 17 poles, and the FPKR uses a steel housing. Published series figures include circuits 18, current per circuit 100 A, voltage 500 V. It is made by Wabtec Corporation; Specify Motion can help source it or propose an equivalent.
Who makes the Stemmann-Technik FP series (FPKK, FPKR)?
The Stemmann-Technik FP series (FPKK, FPKR) 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 circuits of the Stemmann-Technik FP series (FPKK, FPKR)?
The published series maximum circuits is 18. Individual models and sizes in the FP series (FPKK, FPKR) 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 FP series (FPKK, FPKR)?
Yes. On published figures, Multi-channel Slip Ring and High & Low Temperature Slip Ring are the closest match from our supply network. An engineer confirms the fit against your application before recommending anything.
What is a split slip ring?
A split slip ring has a rotor and housing made in two halves, so it can be fitted around an existing shaft without removing the shaft or its bearings. It suits retrofits and large machines where disassembly would be costly. Expect tighter installation tolerances and possibly a lower speed rating than a one-piece unit.
What is a contactless slip ring?
A contactless slip ring transfers data, and sometimes power, across rotation without sliding contacts, using capacitive, inductive or optical coupling. There is no wear on the data path, so life is long and very high data rates are possible. Contactless power is usually limited, so many designs combine a contactless data channel with conventional power rings.
Further reading: How to select a slip ring · How to specify a slip ring · Slip rings
Other slip rings series
Spec builder
Specify what you need instead of FP series (FPKK, FPKR)
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
Let our experienced engineers do the hard work for you
Tell us how you use the Stemmann-Technik FP series (FPKK, FPKR): the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
- 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.