Key specifications
Specifications
| Parameter | Value | Notes |
|---|---|---|
| Typical bore | 25.4 mm or 38.1 mm | Matched to the yaw shaft or hub penetration |
| Circuit count | 6 / 12 / 18 / 24 / 36 | Power, control, safety chain and communications |
| Current per ring | 5 A / 10 A / 20 A | Parallel rings for high-current pitch drives |
| Voltage | 440 V | Dielectric strength 800 VAC (power) |
| Rotation speed | Up to 250 rpm | Yaw is slow; continuous duty still matters |
| Life expectancy | 20 / 50 / 80 million revolutions | Specify the top tier for 20-year service |
| Operating temperature | −30 to +80 °C | Cold-start performance is the usual limit |
| Protection class | IP65 / IP68 | Sealed against driven rain, dust and washdown |
| Contact material | Six-element alloy wire, gold plated | Stable resistance at low signal levels |
| Mounting | Flange or through-shaft | Custom flange patterns quoted per drawing |
Where slip rings sit in a turbine
- Yaw joint (nacelle to tower) — main power, control and safety chain across the rotating nacelle
- Pitch system (hub) — blade pitch power and feedback signals at the hub root
- Condition monitoring — sensor and vibration data from rotating components
- De-icing and lightning protection — heating circuits and grounding paths
What actually fails in the field
Wind slip rings rarely fail from electrical overload. The failures that take turbines offline are usually:
- Seal degradation — driven rain and salt air get past a worn seal, then moisture reaches the contacts. IP65 is the practical minimum; IP68 for hub-mounted units exposed to washdown.
- Cold-start wear — at −30 °C grease stiffens and contact resistance rises. Specify the temperature range explicitly rather than assuming the default.
- Vibration-induced fretting — continuous small movement between contact and ring erodes the plating. Rigid mounting and correct concentricity matter more than people expect.
- Under-specified life — a 20-million-revolution tier is fine for a test stand, not for a 20-year yaw joint. Choose the 80-million tier and confirm the duty cycle.
Selection checklist
- Shaft and bore — measure the yaw shaft and confirm the through-bore with clearance for thermal growth.
- Circuits — list power, control, safety chain and data separately; mixed circuits need internal separation.
- Environment — temperature band, humidity, salt, altitude; pick IP65 or IP68 accordingly.
- Life target — 20, 50 or 80 million revolutions, matched to service interval.
Frequently asked questions
Can one slip ring carry power and Ethernet on a turbine?
Power and signal circuits can share one housing with internal separation. For Ethernet or fieldbus, tell us the protocol and data rate — those need controlled impedance and shielding, which is a different contact arrangement.
What protection class do you recommend offshore?
IP68 for hub-mounted units exposed to washdown; IP65 minimum elsewhere. Note the rating covers ingress, not corrosion — for offshore duty tell us and we will discuss housing treatment.
How do you handle lightning protection?
Grounding paths and surge handling are machine-level design decisions. We can provide a dedicated ground ring and confirm insulation clearances; the surge protection itself sits outside the slip ring.
What is the lead time for a wind-rated unit?
Standard configuration is typically about one week. Units with custom flange or extended life tier follow the drawing — we confirm the date with the quote.
Related products
- 38.1 mm bore series — common for yaw shafts
- 25.4 mm bore series — for smaller hub penetrations
- 50 mm bore series — large shafts and hose bundles
- All through-bore slip rings
Specifying a slip ring for a wind turbine?
Send the yaw shaft size, temperature band and circuit list — you will get a technical recommendation, usually within 5 hours.
