Through-Bore vs. Capsule Slip Rings: Which Is Right for Your Application?

Choosing the right architecture

Slip rings are available in a wide range of mechanical formats. Through-bore and capsule designs are two of the most common, and choosing between them early can simplify installation, improve reliability, and reduce redesign work.

Through-bore slip rings

A through-bore slip ring has a hollow center that allows it to mount around a shaft or provide a path for pneumatic lines, hydraulic lines, fiber, or other machine elements. It is commonly used in industrial automation, robotics, cable reels, packaging machinery, and indexing systems.

The larger form factor can support higher current, more circuits, and complex combinations of power and signals.

Capsule slip rings

Capsule slip rings are compact, enclosed units designed for applications with limited space and lower electrical loads. Common uses include cameras, gimbals, medical equipment, and small robotic systems.

Despite their small size, capsule designs can carry power, control signals, Ethernet, video, and other data when properly configured.

Which should you choose?

Choose a through-bore design when the assembly must fit around a shaft, accommodate other media through its center, or carry larger circuit counts and current loads. Choose a capsule when compact size, low weight, and simple mounting are the main priorities.

Final selection should also account for speed, duty cycle, environment, signal type, and service-life expectations.