How To Specify A Slip Ring

Slip rings are always part of a larger mechanism with a need to pass specific electrical power and signal circuits through a rotating surface. The mechanism the slip ring is part of operates in an environment such as an aircraft or a ship. Therefore, to create a slip ring design that will succeed in its application three criteria must be satisfied:

1. Physical dimensions, including attachment arrangement and de-rotating features
2. Description of circuits required, including maximum current and voltage
3. Operating environment, including temperature, humidity, salt fog requirements, shock, vibration

More detailed slip ring requirements include:

• Maximum resistance between rotor and stator, usually expressed in milli-ohms
• Isolation between circuits, expressed in dB
• Isolation from EMI sources outside the slip ring housing, also expressed in dB
• Starting and running torque, expressed in in-lbs
• Weight
• Data circuit descriptions

Common extra features that can be incorporated in a slip ring assembly include:

• Connectors
• Resolver
• Encoder
• Fluid rotary unions
• Coax rotary unions
• Fiber optic rotary joints

Electro-Miniatures can help you identify the specific criteria you need to establish to ensure your slip ring meets your design requirements.