220v 11kw VFD ground

[Phil Mayor]

Hi,

I've got a 220V H300B - 11H/15LS2-A1 VFD, and I was hoping to test it and program it in, (if it hasn't already been done by the manufacturer) however,
once I opened it up to check the terminals, I'm not entirely sure where to put the Ground wire from my UK plug. On my last smaller 2.2KW VFD there was an obvious ground terminal labeled up on the same row as the Live and Neutral but that isn't the case here, so me not being completely savvy with Electrics it's stumped me a little. If anybody has wired one of these up or just knows what to do, could you guide me?

[Neale]

Looks as if it may be the screw terminal between the two 3-terminal blocks but I can't quite make it out from the photo.

The wiring diagram you show says 380V, not 220V - and 11KW is a pretty heavy load for a domestic circuit! Do you have a 3-phase supply?

[Phil Mayor]

Hi Neale,

It is a beast, I don't have 3 phases, but the VFD can be hooked up with either single-phase or three-phase...apparently? The Spindle it's going to run is 9Kw.

The screw terminal between the blocks has PE written above it, and in my 1st attachment above, it states this is a ground but from the diagram, I thought that there should just be a wire from the PE terminal to somewhere on the VFD metal case, it doesn't show it coming from the UK plug side, but maybe that's just my poor understanding of wiring diagrams..?

[Neale]

"PE" stands for "Protective Earth" - should go to the mains earth along with any other exposed metalwork.

Still a bit worried about your supply. For one thing domestic mains is nominal 230V but this is a 380V VFD. Yes, you can run a 3-phase VFD off single-phase - my HY VFD does and works fine - but at your VFD power levels it's likely to derate the VFD which won't be able to deliver full power. But this doesn't get round the 230/380V issue!

9KW at 230V means a current draw of getting on for 40A. That's not just a bit more than a 13A socket can deliver - it exceeds the rating of the ring main behind it. At 230V, this is hard-wired electric shower or electric cooker stuff.

[Phil Mayor]

Hi again Neale,

This kind of links in with another post I wrote called "Potentially a good problem to have" in the Spindles and Drive Motors thread.

Basically I ordered a 6kw Spindle and VFD
but, cutting a long story, short, it was 'lost in the post' the supplier didn't have any other 6kw left in stock so sent this 9kw out as a gesture of goodwill, FOC. So I now have a much better Spindle/VFD but struggling to power it 😞

I haven't really made myself clear, I will be getting an Electrician in to upgrade my Garage supply, I had planned on getting a single phase 32amp socket for the 6kw Spindle but do you think maybe just upgrade to 3 phase now its a 9kw spindle??

I just wanted to try and get the VFD tested/programmed in and thought as I don't have my Spindle hooked up to it this wouldn't be an issue but I can wait till I upgrade my supply if you think it might not be safe as is...

Phil

[Phil Mayor]

Actually, I think 3 phase is out the question, after a quick Google it's a bit more involved than I realised, it could mean digging up the drive, it's only been done recently so the Mrs won't be letting me do that!

[Muzzer]

It's quite unusual to find a single phase VFD above 4kW or so - and usually of course single phase tends to mean 240V. Looking at the screenshots, this Chinesium example doesn't seem to check for loss of one of the incoming phases, so as long as it sees enough voltage on its internal bus, it will presumably run. I guess the question is whether the undervoltage limit is set too low for it to run off 240V. The other limitation is the maximum phase current on the output. It may be limited to a level that would restrict the net power when running with low input.

A rough and ready solution might be to boost the input from 240V to 360V single phase by connecting a 3kVA 240-120V site transformer as an autotransformer. - this would allow you ~9kW capability and require perhaps 40A total from 240V, if you ever went there.

But when do you really expect to be running 6kW at the spindle? This would mean an heroic material removal rate by our standards. I have a 300A TIG welder that runs off 240V single phase, which requires something like 70A at full chat - not a problem, as I have a 63A feed from my workshop consumer unit - it's perfectly possible.

[Phil Mayor]

Hi Muzzer, when I placed the order they asked me if its 220v or 380v... that sounds like a good option using an Autotransformer, it something I've never used before so would need to look in to more... I'm pretty sure I won't ever be needing/using full power, I would like to cut Aluminium and possibly thin mild steel but 95% of my work would be MDF and Soft/Hard Woods.... which makes me think would Single Phase 32amp not be ok, I could probably get ¾ of full power with 32amps which should be enough, shouldn't it...?

[Phil Mayor]

Sorry I realise this has gone slightly off topic from the original post...