Definition:
A slip ring is a very essential component of electromechanical devices and is used in an array of industries like radars in surveillance systems, microscope, support arm lamps, wind turbines, automation equipment, rotating table, etc.
Its function is to provide electricity to the part from a stationary that rotates continuously in an assembly of equipment, resolves the continuous rotation of 360 degrees and should have the feature to be able to rotate continuously in loops.
Types of slip ring
There are many kinds of slip rings that are available and can be used basis the purpose where it will be used. Some of the types are
Electrical slip ring
· H- through hole slip ring
· M signal slip ring
Signal slip ring
· Fibre optic rotary joint
· USB 2.0 slip ring
· Servo motor encoder slip ring
· Industrial bus slip ring
Pneumatic and Hydraulic rotary union
· Single passage
· 2, 4, 6, 8, 12 passages etc.
Custom slip ring
· Pancake slip ring
· PCB slip ring
· High current slip ring
· High-temperature slip ring
Differences between the slip ring and a commutator:
· The function of a slip ring and a commutator is very similar except the slip ring is continuous whereas the commutator is segmented.
· Slip rings, on one hand, provide a continuous transfer of power, or data especially, in AC motors, as they transfer resistance to the rotor windings.
· On the other hand, commutators belong to DC motors with the function of reversing the armature windings’ polarity of the current.
The process of mounting a slip ring
Figure 1
Figure 2
· Flanged slip rings come with screws that are used to mount a slip ring and washers. The washers have this unique function to protect the rim against intemperate forces. If the machine uses the lock washers, flat washers should be positioned between the lock washer and the rim.
· Slip rings that are used without the rims can be mounted with the use of the stator. The most common practice of doing this is to insert the body of the slip ring into a hole that is comparatively bigger than the OD, through the use of set screws, adhesives, or O-rings after which it is safely secured.
· The rotor can be driven with a pliable drive combination to accommodate differences in the assembly of the machine and axis of rotation slip rings. This process is done with the help of combinations of flexible coupling, Rubber tubing, and heat shrink tubing. For machines that run at 5 rotation per minute or less, the rotor leads combinations can be used as the flexible coupling.
· The external or radial loads cannot be taken care of by slip ring’s bearings and are not designed to support in any way. The rotating parts should be designed, structured and supported in a way to weaken the effect of axial and radial forces to the slip ring bearings to a bare minimum.
· Dust and moisture are an enemy to the slip ring and hence should be taken care of to protect it from the external environmental elements. If the installation of a slip ring happens in an outdoor setting then it must be made sure to be placed in a weatherproof setting to strengthen its longevity.
· The slip ring should be designed in such a way that after the leads are secured, they should not touch or be in contact with any surface of the equipment as it rotates as it might lead to the death of the functions of the slip ring. While routing the wires, the leads shouldn’t be allowed to touch to any side while loading on the slip ring.
· The slip ring should be designed in such a way that after the leads are secured, they should not touch or be in contact with any surface of the equipment as it rotates as it might lead to the death of the functions of the slip ring. While routing the wires, the leads shouldn’t be allowed to touch to any side while loading on the slip ring.
Styles of Mounting:
1) Installation through bore style
This installation is done by fixing the rotary for the inner ring and outer ring. These are also called electrical slip rings and consists of a hole in the center.
2) Installation through Pneumatic hybrid style
This kind of slip ring can be rotated 360 degrees and are used specifically for industrial usage
3) Installation with rotor flange slip ring
This is the one that is present with a flange on the rotor and is secured with the help of screws. It also uses the mount of anti- rotor pole to balance the equipment
4) Stator flange slip ring installation instruction
In this, the flange is located on the exterior of the ring and has the feature of rotating without being fixed to the cable, provided it’s a miniature.
5) Bore rotor flange slip ring installation
This consists of a hole in the middle with the rotor part rotating and the stator part as fixed but it comes with the unique characteristic of working as well with the rotor part as fixed and the stator part is rotating.
6) PCB slip ring installation instruction
This uses the PCB board as a substrate which fixes the ring to the board by pressing them together and coating them with shrapnel and contacts. One characteristic feature is here the PCB slip ring is installed separately individually between the rotor and the stator. This ensures that the rings have sufficient pressure and concentricity.
7) Installation for Multi-channel FORJ
Fiber optic rotary joint is also called fiber optic slip ring which has the capability to treat fiber optics as transmission data which facilitates resolving data transmission between system components of the rotary joint. This is suitable to use in places where large-volume data transmission is required from a fixed position to a rotating position. It is helpful in improving the mechanical property and helps reduce damage to the fiber optic caused by joint rotating.
