The exchange surfaces of the coolers of the electrical machines are mostly made of metals such as copper or copper alloys for the tubes and copper for the fins. As far as air coolers are concerned their surfaces can also be made of steel tubes fitted with aluminium or steel fins, possibly protected.
Tube sheets and boxes for the water distribution are either made of steel or of copper alloys (brass or copper-aluminium) according to the type of the circulating water. For many years SCAM has been manufacturing finned tube coolers. These tubes, externally finned, offer a large surface in contact with the cooling air and allow an optimised heat exchange between the two fluids.