United Equipment Accessories (UEA) recently designed another large crane slip ring solution. This one may not be as tall as some of its predecessors, such as this ship-to-shore gantry crane slip ring, but what the slip ring lacks in height, it makes up for in weight. While UEA has built many large crane slip rings in the past, this is the first one to include prewired harnesses. The harnesses add a significant amount of weight, making the unit roughly 1,800 pounds (816.5 kg). This 57-inch (1447.8 mm) tall, 7-inch (177.8 mm) bore slip ring comprises three smaller slip rings totaling 31 circuits. The upper slip ring has 24, 15-amp circuits dedicated to communication, and the lower two slip rings have a total of 7, 600-amp circuits dedicated to power.
This 31-circuit slip ring weighs so much because of the prewired harnesses. The power circuits are hooked up with 7, 777-gauge diesel locomotive (DLO) cables, with 24 feet (7.32 m) running out of the mounting tube and seven more cables running 33 feet (10.06 m) out of the backside of the enclosure. The DLO cable used in this application is rated at 2,000 volts and is highly flame resistant. It also has an O.D. of 1.38 inches (35.1 mm) and weighs 2.73 lbs. (1.24 kg) per foot. That is over 1,200 pounds (544.31 kg) of cable for just seven circuits! The lugs that are used to make the connections require the use of a 12-ton hydraulic crimper. Two separate crimps are made on each lug when installed on the cable. The lugs are then landed onto bus bars located on the brushes and the top of the cores.
In addition to this crane slip ring design, UEA has designed and manufactured slip rings for various large cranes, including offshore cranes, dredge cranes, and ship-to-shore gantry cranes. Interested in talking to our engineering team about your custom slip ring needs? Contact us today!