Huanyang VFD current draw measurements.

[magicniner]

Nearly all VFDs (and that includes servo drives, as they are essentially a VFD) have huge instantaneous switch on current surges. When first powered up, they appear as a short on the supply until their internal capacitor bank charges.

Yet if you follow general industrial practice and leave them powered on, controlling the motor with signals and not VFD input power switching, the ramp-up options give you soft-start options which dramatically reduce surge allowing multiple machines to be run safely on circuits which would not normally allow this.

I'd appreciate links to technical write-ups of examples of harmonic wiring burnout due to absence of filters as the only machine I run a filter on is my CNC mill where the control system is sensitive and requires a filter and I have 6 other VFD systems in the workshop,
Regards,
Nick

[m_c]

Nick, this link is the first one I've found that explains a bit about the hazards - http://www.ecmweb.com/content/fundamentals-harmonics

I'm in no way an expert, but the problem with the higher order harmonics, is the higher the frequency passing through a conductor, the more the current travels towards the outside of the conductor. IIRC it's called the skin effect, and is why the insulation is far more likely to fail, despite wiring being adequately sized for the rated voltage/current.

[magicniner]

No mention of Drive, VFD or Inverter Drive?