Slip rings are electromechanicaldevices that transmit power and electrical signals through static to a rotatingcomponent. Rotary joints, electrical rotary joints, sliding contacts, and othernames are to such devices. With its continuous rotation capability, it is clearthat this solution hugely simplifies assembly and eliminates the need forcomplex articulated wiring systems and the associated risk of damage anddowntime, thereby significantly reducing maintenance requirements. Slip ringscan transmit energy, data, or both depending on the transmission technology.Their power carrying capacity ranges from mW to MW, depending on theapplication and configuration. The data can be digital or analog I / O,including Fieldbus data up to 1 Gb / s.

Typesof Slip Rings:

By developing several contacttechnologies that utilize different configurations and materials due to thewide range of uses for slip rings.There are currently four different types of contacts. 

Wireless:

Wireless slip rings are a relativelynew product category. They work on the principle of capacitive or inductivecoupling for power and signal transmission by exciting high-frequency coilswithout making contact between the rotating and static components, which canalso be separated by unique materials if necessary. They are less efficientthan other solutions in general, and the efficiency loss is directlyproportional to the distance between the mated components. In reality, theadoption of this solution has not been yet wider. The absence of wear and thepossibility of configurations with a high degree of tightness/protection areits main advantages.

Fiber Brush:

It is currently the most widely usedtype due to its high flexibility, making it suitable for versatile applicationsranging from high power transmission to high-frequency signal transmission. Thebrushes can be nanofiber for small capsule collectors, and they can bemultifiber while for larger collector rings. Multi-fiber slip rings withbrushes provide the best durability and contact quality: the low frictionbetween the contacts reduces wear and dust.

Conductive Blocks:

Conductive block slip rings are alsoknown as carbon brush slip rings. These are probably the most basicconfiguration. They are used primarily in low-tech applications, such as powertransmission or simple signal transmission. The brushes are of blocks shape tomake contact with the rings. The material of the block can range from simplegraphite for power transmission to more complex precious metal alloys for signaltransmission. Spring-loaded brushes are usually helping to maintain contactwith the rings in the event of shock and vibration and compensate for wear.This technology has a high wear rate and requires routine maintenance toprevent the accumulation of conductive dust in the slip ring.

Metal in liquid form:

Because of its high performance in asmall package, it was the most commonly used type. It does not make use of abrush/ring configuration. Instead, it transmits power and signals betweenstatic and rotating components like rotary joint via a conductive liquid metal.Mercury is the most commonly used liquid metal for this purpose, though agallium (Ga) alloy is now occasionally used.