When helping a customer specify or design a slip ring for their needs, circuit ratings are one of the most critical pieces of information. Customers ask United Equipment Accessories (UEA) how many amps we can put through a slip ring and at what voltage. This is an open-ended question as UEA is a custom slip ring company, continually broadening our product range.
The typical maximum ratings for our slip rings are 600 amps and 600 volts. This is what UEA’s standard slip rings are designed for. This, however, depends on the size of the slip ring, which can be driven by the application and customer needs. The limiting factor for our current ratings in smaller slip rings is the size of wire and/or buss bar you can get inside the core of the slip ring.
Because UEA is a custom slip ring manufacturer, UEA has worked with higher amperages and voltages. We build slip rings weekly that are rated well beyond 600 volts, and we could certainly go higher given adequate space. We have also designed specific assemblies to handle 900 amps for particular applications. It gets more difficult with higher voltage and amperage ratings as the spacing and size of conductors must grow, so the entire slip ring assembly can get very large.
One question often asked is if the slip rings are derated when not rotating. In UEA’s case, no. Our slip rings are designed for continuous power. If we rate a circuit to handle 50 amps, it will operate 50 amps 100% of the time whether it’s rotating or not.
Another question is regarding very low or no current or voltage applications. Our slip rings and brushes are designed to run “dry” with no current or voltage. So, in applications with only a ground, shield, or very low currents, there are no issues.
Again, UEA’s standard slip ring line is designed to handle 600 amps and 600 volts, but we focus on providing solutions for our customers specific to their needs and go below these limits.