Comparison of low and medium voltage variable frequency inverters

The author investigates the various technologies available in the cement industry for medium-voltage variable-speed applications. He focuses on how to decide what type of technology is best for a cement plant and whether there is a clear-cut advantage in using one type over another. He suggests a numer of variables to consider, including harmonics, efficiency, line isolation, the cost of equipment, installation cost, and the application environment. He concludes that, when considering inverter technologies, a plant manager can be confident that a low-voltage inverter with transformers and a direct-connected medium-voltage inverter are equal in technology, and suggests that the inverter that best minimizes harmonics and losses should be considered when evaluating a final selection of equipment