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Title: Fan bearing damage due to EMI from high power curcuits Post by: Opcom on July 31, 2023, 08:22:27 PM The source is certainly a reputable manufacturer of fans and blowers. Seems to affect ball bearing fans. Has anyone any consideration or experience of fan bearing issues?
"Cautions for Use of a Cooling Fan in the Vicinity of a Power Switching Circuit (prevention of electrolytic corrosion)" https://products.sanyodenki.com/info/sanace/en/technical_material/powerswitchingcircuit.html Title: Re: Fan bearing damage due to EMI from high power curcuits Post by: WD8BIL on August 01, 2023, 07:54:39 AM Ya know Patrick, I never really considered that. The fans in our transient generators here in the lab do make quite a bit of bearing/bushing noise.
They run EFT and surge tests everyday in the 1-4KV ranges (61000-4 series tests). We just got a 3rd generator a few weeks ago. I'll keep an ear on it and see ifn the fan noise grows over time. Interesting! Buddly Title: Re: Fan bearing damage due to EMI from high power curcuits Post by: W1RKW on August 01, 2023, 08:16:48 AM If there were some actual numbers in that piece I might believe it. what level is considered high power/high voltage? This is very subjective. Maybe oxygen free monster cable will help.
Title: Re: Fan bearing damage due to EMI from high power curcuits Post by: K8DI on August 01, 2023, 12:41:35 PM Bearing damage from discharge of electromagnetically induced voltages on a motor shaft is a known issue.
Here’s an approachable article: https://www.vibescorp.ca/learn-about/shaft-currents/ (https://www.vibescorp.ca/learn-about/shaft-currents/) Ed Title: Re: Fan bearing damage due to EMI from high power curcuits Post by: W3SLK on August 01, 2023, 07:45:20 PM So back when I was a service engineer in a different lifetime, I repaired industrial balancing machines. One service call took me to GE Erie where I was met by the plant manager who said, "You gotta help me! I'm loosing $50MM a day!" Our machines were used to balance the armatures for the locomotive traction motors and the main armature for the locomotive alternator. Those armatures weigh about 10K lbs and are balanced at 900 RPM. Our machines were rated to weld on the work supports. However some new operator was welding the balancing weights in place with the ground not on the shaft of the armature, (it was a strap in the shape of a hook), he hooked the grounding clamp to the base of the machine! Arced through about $20,000 worth of bearing supports. When I spun the bearings it sounded like rice crispies! Don't use bearings as a 'path' to ground! AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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