Siemens Automation and Drives (A&D) is exhibiting the new built-in units of the Sinamics S120 converter series, featuring liquid cooling, at the SPS/IPC/Drives 2006 trade fair.
These units are especially suitable for use in dusty and aggressive atmospheres, making them a cost-saving alternative to air-cooled units. It is mainly the efficient cooling concept and the possibilities of heat recovery that are responsible for the reduced operating costs. Moreover, the compact design takes up less space and the low noise level renders sound-insulation measures superfluous.
The liquid-cooled version of the Sinamics S120 is available for power outputs up to 1200kW. Parallel configuration facilitates power outputs of up to nearly 4.5MW. They are suitable for applications where tight space restrictions, high temperatures and a dusty or aggressive atmosphere prevail. This is the case in ships, conveyor belt systems in mining, paper factories, printing and plastic machines, the food and beverages industry or gearbox test bays. With liquid cooling, hermetically sealed switching cabinets with high degrees of protection can be easily achieved, irrespective of the ambient air.
Liquid-cooled units are also suitable for use at high ambient temperatures. Because liquid cooling removes all the heat from the switch room, no additional air-conditioning is needed. The associated installation, maintenance and operating costs normally entailed are therefore eliminated. In addition to the savings achieved due to the highly efficient cooling concept, costs are also lowered as a result of heat recovery. The water that is heated during the cooling process can be used for process heat, room heating or heating of service water.
This more intensive form of cooling, enabled by the use of liquid, makes the inverter very compact. Liquid-cooled units require up to 60 per cent less space than air-cooled units with the same power rating. This facilitates modular machine concepts and lower construction costs due to smaller switch-rooms. Another advantage of liquid cooling is the lower noise levels. The units do not need a fan. Given the typical noise emission level of only 52dB(A), no additional sound insulation measures are necessary.