What the slip ring has to handle
- Combined electrical slip ring and single- or multi-port air union for fixtures and valve banks
- Three-phase power and control circuits in one unit where tooling has motors
- Fieldbus/Ethernet support (Ethernet, PROFINET, PROFIBUS, DeviceNet, CAN) on twisted, shielded pairs
- Through-bore mounting inside the table's centre column to save footprint
- Ingress protection suited to the plant, up to IP67 for harsher areas
- Pre-wired harnesses or connectors on flying leads to simplify assembly
- High cycle life with continuous indexing
Typical figures
| Ingress protection | Index-table slip ring series available up to IP67 |
|---|---|
| Data | Ethernet, PROFINET, PROFIBUS, DeviceNet, CAN supported |
Example figures from the published sources listed below. Your requirement may differ; an engineer will confirm against your duty cycle.
Recommended slip ring types
Standards to consider
- IEC 60204-1 - electrical equipment of machines
- ISO 12100 - machinery safety risk assessment
- IEC 60529 - IP code for enclosure protection
The complete system
A slip ring rarely works alone. For packaging machines & rotary indexing tables it is usually specified together with:
- rotary indexer or cam drive
- servo motor
- servo drive
- absolute encoder
- valve terminal
- brake
Specifying these together avoids mismatched connectors, cable routes and feedback interfaces, and gives you one point of contact for the whole axis.
Common problems to design out
- Fieldbus faults from noise coupling into unshielded signal rings
- Air leaks or contamination in the rotary union
- Brush wear causing intermittent sensor signals
- Wiring damage at lead exits during installation
Series used in this application
Frequently asked questions
When does a rotary index table need a slip ring?
When it has more than two stations or turns continuously in one direction, a cable loop can no longer follow it. A slip ring, often with an air union, then feeds power, signals and air to the fixtures.
Can one unit carry power, fieldbus and air?
Yes. Electro-pneumatic units combine electrical rings with air passages, and a single unit can carry three-phase power together with communication circuits. Twisted-pair signal wiring helps keep communication faults down.
Where should the slip ring be mounted on an index table?
Many tables have a stationary centre column with a through-housing, which lets the slip ring and air union sit inside the table. That avoids overhead or external mounting and keeps the machine footprint small.