SECONDARY BUS BAR SYSTEMS

Secondary bus systems transfer the electrical current from the transformer to the furnace cable attachment through the vault wall. The photographs below are two examples of bus systems fabricated at Erie’s plant in Medina, Ohio.

Above: Water cooled secondary bus system. Water-cooled section fabricated from Oxygen-free, high conductivity seamless copper tube. ETP copper plates used as stubs in the fabrication of this critical piece of equipment are skillfully welded together by certified welders.	Above: Air cooled secondary bus system fabricated from cold-rolled ETP copper plate. Electrical conductivity is in excess of 100% IACS. Forming, drilling and finishing functions must be precise for this type of equipment to function properly in the secondary circuit.

Both air and water cooled systems utilize kiln-dried hard timbers for suspension.

Bus systems are sized by determining the proper amount of cross-sectional area of copper required to carry the maximum amount of current the transformer is capable of delivering. The commonly accepted design criteria for making this determination, assuming high conductivity copper materials are being used is: 3,000 amps per square inch for water cooled applications and 900 amps per square inch for air cooled applications.

Erie Copper Works fabricates, maintains and designs secondary bus systems. Regardless of design method or attachment to the transformer or suspension system, bus systems are subject to failures caused by dirt, insulation breakdown or arcing at loose connections. In addition water cooled systems can fail because of water leaks or condensation which forms on the water cooled sections when certain conditions exist.

Call Erie Copper if you would like specific recommendations regarding routine and periodic maintenance procedures for your secondary bus system.

Click on here for information about Bus Tubes