VFD cable article

[Kitwn]

I'm pretty sure there wouldn't be any problems with commoning up the 3 earth conductors to a single pin at the spindle, it's all about balancing inter-conductor capacitance along the length of the cable, a few cm at the far end is unlikely to upset things. And the outer screen would be best connected only at the VFD end to avoid HF earth currents, so likely you could do it with a standard 4 pin plug - if you could fit the rather fat cable into said plug of course.

I have to say I'm unconvinced that's worth the expense. Coming from a communications background, to avoid significant radiation of noise I'd want each winding fed with it's own balanced, twisted pair. Telephones have been doing it this way since Alexander Graham Bell was in charge, twisted pairs minimise both radiation and reception of noise, and Ethernet cables are done the same way. I don't know if these VD cables are constructed as three twisted pairs but for minimal noise radiation they would need to be.

While we're on about it, using a twisted pair rather than loose wires for connecting limit switches etc. to your BOB might help reject noise pickup even for non-balanced inputs.

Kit