Shaft Current Training Part 1 What Are Shaft Currents Youtube Learning what shaft currents are is the first step in fixing them. destructive shaft currents are prevalent in vfd controlled motors. but they also cause dam. With the introduction of vfd's, shaft currents became a significant problem for motors, even ones much smaller than had previously experienced problems. the cause of electrically induced bearing damage & shaft currents. the earliest known in depth study dealing with eibd (electrically induced bearing damage) was completed in 1994 by hugh boyanton.
Ppt Shaft Current Powerpoint Presentation Free Download Id 1302109 Technical guide no. 5|bearing currents in modern ac drive systems 13. voltage drops. if the value of this inductance is high enough, the reactance at the upper range of typical common mode current frequencies, 50 khz to 1 mhz, can support voltage drops of over 100 volts between the motor frame and the inverter frame. Bearing currents are high frequency currents that are caused by voltage on the motor shaft, which drives a discharge current through the motor bearings. this is rarely a problem in electric motors operating on line voltage. but variable frequency drives (vfds) put out pulse width modulated voltage, which can be a big problem for inverter fed. You can indirectly measure bearing current by looking for sudden collapses in shaft voltage. these indicate a discharge (arc) through the bearings. you can measure shaft voltage with an oscilloscope like the aegis shaft voltage tester, or any scope with bandwidth of at least 100 mhz. multimeters don't work because shaft voltage changes too quickly. Webinar recording. shaft and bearing currents. shaft currents caused by operation from a vfd, and how to tell the difference between the two. this webinar also discusses and compares methods to mitigate shaft currents and explains why the different causes of shaft currents require different solutions. it covers:.
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