Real power savings are observed in a case study comparing a VRT (Variable Reactance Transformer) and an IGBT/MFDC power supply in a furnace retrofit. The IGBT (Insulated Gate Bipolar Transistor) is the power controller and MFDC (Mid Frequency Direct Current) is the transformer portion of the power supply. The VRT was replaced with a similarly sized IGBT/MFDC power supply. Other variables remained essentially equivalent and provided a good comparison between the power consumption of a VRT versus an IGBT/MFDC system in an equivalent furnace. IGBT/MFDC offers cost savings through less kilowatt usage, lower peak demand, and better power factor when compared to other power controls. From this case study, we will demonstrate a 40 percent reduction in kilowatt consumption, a 14 percent reduction peak demand, and a high displacement power factor throughout the cycle. All of this results in lower costs for furnace operation.

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