Because United Equipment Accessories builds only custom slip ring assemblies there is no simple formula to answer the question “What does a slip ring cost?” Virtually every slip ring assembly is unique to a specific customer and proprietary to that customer.
There are a variety of factors that affect the cost of a slip ring, starting with the circuitry required to meet the needs of the application. The number and ratings of the circuits generally determine the bore size of the slip ring. The higher rated circuits, both for current and voltage, require both larger brush assemblies and wider rings or extra insulation between circuits, and therefore add cost. The cost per circuit is also highly dependent on the materials used for the brush contacts and for the rings in the core stack. Cost per circuit increases from the UEA standard copper graphite on brass ring circuits up to silver graphite brush contacts on coin silver or plated silver rings with a variety of possible combinations between the least and most expensive options.
In some cases, the application may determine the bore if the slip ring must fit over a specific center shaft or allow passage of one or more pneumatic, water, etc. lines through the center of the assembly. There are other applications where a 1.50” bore slip ring might normally be suggested but space restrictions force the use of a 0.50”-1.00” bore assembly. While the 0.50”-1.00” bore and 1.50” bore assemblies are very similar in cost per circuit, the general rule is that the larger the bore the more expensive per circuit.
Another of the custom options offered by UEA is the addition of wiring harnesses for brush leads, center leads or both. These can include discrete wires with the correct wire gage matched to the current and voltage rating of each circuit, jacketed cables or combinations of both. The lengths of these harnesses are to customer wants and needs and can include connectors for easy attachment to mating harnesses. Options for harness-covering include everything from tape wrap to heat shrink to braided nylon. Other options have included flexible metallic and non-metallic conduit, split conduit and vinyl or silicone sleeves over the harnesses.
Not to be forgotten is the enclosure, if required, and the mounting position of the slip ring assembly. A simple enclosure for ‘upright’ mounting of the assembly with protection from rain is less expensive than an enclosure for an assembly that is mounted below a hydraulic swivel and must be sealed against road spray and from moisture from above passing through the center of the hydraulic swivel.
The custom nature of UEA slip ring assemblies, including the ability to mix and match circuit current and voltage ratings within one assembly, provides the opportunity to closely match a customer’s exact needs but also requires that many details be supplied before an accurate quote can be provided. Quantity price breaks can be supplied, but are more dependent on run quantities per order than on total estimated annual usage because of the labor intensity of the custom assemblies.
Please contact us for your slip ring needs but don’t be surprised if we ask for more details to accurately quote, and hopefully build, an assembly to exactly match your requirements.
Senior Project Engineer