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the article citations: time:2016-08-14 10:34:14
the causes and effects of -supplied motor shaft and , as well as measures to counteract them, have been exhaustively covered in literature. however, as a drive and motor supplier, we frequently receive requests for information on this topic.
basically, shaft currents are induced because of the high frequency of the voltage pulses sent to the motor from the . recall that a pulse-width modulated vfd creates a synthesized sine wave by firing its output transistors many thousands of times per second. these pulses form sent along the motor cable to the motor. since impedance is inversely proportional to frequency, the capacitances of the cable and motor present little or no impedance to these high-frequency pulses. as a result, circulating currents can readily flow in the . with sufficient magnitude, and in the absence of corrective measures, these shaft currents can pass through the bearings and races to the motor frame, causing bearing pitting or “fluting” – regular, tightly spaced grooves on the bearing races – via a process referred to as electric discharge machining (edm). ultimately, these irregularities will cause .
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basically, shaft currents are induced because of the high frequency of the voltage pulses sent to the motor from the . recall that a pulse-width modulated vfd creates a synthesized sine wave by firing its output transistors many thousands of times per second. these pulses form sent along the motor cable to the motor. since impedance is inversely proportional to frequency, the capacitances of the cable and motor present little or no impedance to these high-frequency pulses. as a result, circulating currents can readily flow in the . with sufficient magnitude, and in the absence of corrective measures, these shaft currents can pass through the bearings and races to the motor frame, causing bearing pitting or “fluting” – regular, tightly spaced grooves on the bearing races – via a process referred to as electric discharge machining (edm). ultimately, these irregularities will cause .
(, and )
follow us via e-mail website .
