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Open-Delta Systems Affect VFDs

Sep 24, 2012

p>Variable frequency drives (VFDs) have been commonly used in industrial and commercial applications for decades. The basic design topology of the VFD with a diode bridge, DC bus capacitors and insulated gate bipolar transistor (IGBT) output has proven to be reliable and beneficial from application and financial perspectives. In general, these applications have been installed on a balanced three-phase power supply, meaning that the impedance line to line is balanced. Therefore, under normal conditions, the voltage and current are balanced phase to phase. While there can be differences relative to ground—which may be done intentionally for single-phase loads such as lighting—the phase-to-phase relationship remains balanced.

 

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