
Processing plants are filled with motors that drive pumps, fans, augers, compressors, conveyors, mills, mixers, and other equipment. Many of these motors need or could benefit from a reduced-voltage soft start or a variable-frequency drive (VFD). Both soft starters and VFDs substantially reduce the electrical and mechanical shock caused by across-the-line starting, and both help reduce electrical demand by reducing a motor's start-up current.
Soft starters and VFDs can reduce field building or inrush currents and machine starting torque by as much as 30% to 75% when compared to an across-the-line starter.
In applications such as pumps and compressors, which can require many starts per hour to maintain critical process flows or pressures, these reduced starting currents result in significantly less motor heating and longer motor life. A softer or less rapid increase in motor torque at motor starting can also greatly extend the life of belt-driven and mechanically geared equipment.
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