Discuss Wiring Multiple VFDs off Dryer Plug for Multiple 3-phase Motors in the Electrical Appliances Forum area at ElectriciansForums.net

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Posted this to the DIY section since I'm not a business or employee in this matter but it feels more appropriate (and might actually get responses) here.
Hi all, I'm new here but have posted on Hobby-machinist and Practicalmachinist forums.

I want to wire up an electrical box for a milling machine. My input is a single dryer plug NEMA 10-30 so no grounding wire, I'm using neutral as ground here and my 10-gauge 4-wire cable is just going to have a floating green wire not attached anywhere.
The mill has three 3-phase motors, one 1hp spindle motor and two 1/4hp feed motors. These will be powered by two Teco L510 VFDs. The large VFD, rated for 3hp, will run the spindle, and the small VFD, rated for 1hp, will run the two feed motors. The small VFD will run at 60 hz always, while the large VFD will have its frequency varied to give various spindle speeds.
My plan and work so far is to wire the two VFDs in parallel, and then the two motors connected to the small VFD also in parallel.

The manufacturer recommends some fuses for the VFDs (Bussman 50FEs for the large VFD and Bussman 20CTs for the small VFD). Should these be placed on a DIN rail, 3 fuses right before each input to the VFDs (including neutral-ground)? What other protections do I need? A contactor?
Before I had both of these VFDs, I wired this same setup using a Teco and a cheap eBay VFD, and I believe a bad grounding job (open neutral??) caused both VFDs to pop when I tried to run them at the same time. Any input here is appreciated too.

Pic shows the progress so far, I haven't wrapped the 3-way connections in electrical tape yet, nor wired the inputs since I have to get this mounted to the mill first. The two (future) connections to the spindle motor and the pair of feed motors can be seen on the right.
 
TL;DR
Looking for help wiring up two VFDs to three 3-phase motors. Mainly what extra bits may be needed and if the plan is flawed.

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