I spent some time with the spectrum analyzer but did’t have much luck in isolating the sink for the noise. I just verified that my VFD does indeed produce a large amount of noise between low kHz and about 10MHz! I did some re-routing of wires and replaced some that weren’t shielded. I ordered some ferrites for the VFD-motor wiring and my computer I/O extension cabling which will be here in a couple days.
However, I did find the source of the main problem! It was indeed my keyboard. Not the USB wiring from keyboard to pc, but the keyboard ITSELF is very sensitive to the noise created by the VFD. If I move the keyboard to the very extreme end of it’s (rather long) usb cable the problem disappears completely. 6” closer to the cabinet and noise reappears. Apparently the noise is being interpreted as key presses by the keyboard circuitry. I replaced the new water resistant Logitech keyboard with a very old Apple keyboard I had lying around and no more random characters! I also had a second problem where the VFD would shut down somewhat randomly which I thought was related to this noise as well. That turned out to be an over current condition at very low rpm. Tweaking some settings fixed that. The Rasmi input filter, and various re-wiring and shielding I did was probably not needed, but in the long run perhaps it will save me from other problems. Thanks, for all the input, -Tom ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
