Key specifications
Specifications
| Parameter | Value | Notes |
|---|---|---|
| Bore (through hole) | 38.1 mm | 1.5 inch nominal; clears larger shafts and cable bundles |
| Outer diameter | 99 mm | Bracket and clearance check recommended |
| Circuit count | 6 / 12 / 18 / 24 / 36 | Higher counts quoted with drawing |
| Current per ring | 5 A / 10 A / 20 A | 20 A from 25.4 mm bore upward |
| Voltage | 440 V | Dielectric strength 800 VAC power / 300 VAC signal |
| Rotation speed | Up to 250 rpm | Confirm duty cycle for continuous operation |
| Life expectancy | 20 / 50 / 80 million revolutions | Selected at order |
| Temperature | −30 to +80 °C | Special ranges on request |
| Protection | IP51 / IP65 / IP68 | Sealed variants for harsh environments |
| Contact material | Six-element alloy wire, gold plated | Low-noise precious-metal contacts |
Typical applications
- Large rotary tables — power and signals on a heavy turntable with a central shaft
- Wind turbine pitch systems — power and control across the rotating hub
- Cable reels and hose reels — electrical transfer while the drum turns
- Packaging carousels — multi-station machines with many sensors per station
- Marine and offshore winches — sealed variants for salt air and washdown
What the extra bore buys you
Going from 25.4 mm to 38.1 mm is not only about shaft size. The larger bore and 99 mm frame give you three practical gains:
- Room for more through-lines — a cable bundle plus a pneumatic or hydraulic line can pass together, so one joint serves both power and fluid routing.
- Better thermal headroom — more surface area means more continuous current per ring before heat becomes the limit.
- Easier wiring access — a bigger frame leaves space to reach terminals and route leads without kinking.
Frequently asked questions
Can I pass a pneumatic line through the bore?
Yes, if the line diameter and bend radius fit inside 38.1 mm alongside any cables. For combined air and electrical transfer, tell us both requirements — a gas-electric hybrid may be the better single-unit solution.
What is the maximum total current?
Per-ring limit is 20 A. Total depends on how many rings are loaded at once and the thermal design — send the simultaneous load profile for confirmation.
Is this series suitable for outdoor use?
IP65 is the usual minimum outdoors. For washdown or temporary immersion, specify IP68. Note that the IP rating covers ingress, not corrosion resistance — for marine duty, tell us and we will discuss housing treatment.
What if I need more than 36 circuits?
Higher counts are possible with a custom frame and drawing. Above 36 circuits the frame size grows, so confirm your available space first.
Related products
- GK3899 — 38.1 mm bore, 99 mm OD, 6–36 circuits
- 25.4 mm bore series — for shafts up to about 1 inch
- 50 mm bore series — for larger shafts and hose bundles
- All through-bore slip rings
Need a 38 mm bore slip ring?
Send the shaft diameter, what passes through the bore, and your circuit count — we will confirm the fit and quote, usually within 5 hours.
