Best option for 3 phase

ojored · 13-11-2017 11:39pm #1

Hi all, I had this up on the electrical section but got no takers. I hoping someone maybe able to help.

I've just purchased some equipment for my workshop as follows;
1. Lathe
2. Milling Machine
3. Bandsaw
4. 360amp Mig Welder
They all use 3 phase power, the largest motor is on the milling machine and it's rated at 2.2kw. I don't have a 3 phase supply and don't intend to get one as this is only for my own bits and pieces. They will not be used all the time and only one machine will be in use at anyone time. I also intend to add more equipment e.g. plasma cutter 80 - 100 amp and a pipe bender etc.
I was thinking of getting a 10 - 15kva 3ph generator to give a true 3ph supply (not sure if this is a correct statement). I have looked at a 3ph converter but I'm not sure if they are suitable for the mix of equipment I have now and in the future.
I'm not from an electrical back ground and would greatly appreciate any advice on functionality/cost options and any recommendations you may have, tks.

14-11-2017 12:50am

You can spend a lot of time trying to find cheap ways to get what you need. It will be wasted time. Rotary converters are a viable option only if you already have suitable motors to build with.

You can buy a 3 phase generator, as you mentioned, which is another thing to fuel, service and house somewhere. Noise, exhaust.. Not for me anyway.

You can pay mad money to get a 3ph supply run in from the closest transformer/pole. Mad, mad money, assuming it's into a domestic garage/shed. No idea what the networks charge is for agri buildings but I imagine it's not easy to pay for anyway.

The only simple solution and arguably the very best option (aside from a grid connection if that's within your means) is a digital converter. At 2.2kw you're into about 3HP on the mill. I'd oversize the converter (work at 50-60% design capacity, it will be more efficient at that anyway) to give you some flexibility and headroom for future machinery/upgrades. Don't cut corners now as it'll be a very false economy.

So, 230/240v single to 415v three phase, rated at about 5HP will do the job.

New:

https://www.ebay.co.uk/itm/5-HP-240V-to-415V-DIGITAL-PLUG-PLAY-3-PHASE-CONVERTER-INVERTER-LATHE-MILLING/152639187057?epid=17004048532&hash=item238a012871:g:JTcAAOSwpRtZeO1l

Used:

https://www.ebay.co.uk/itm/5-HP-240V-to-415V-DIGITAL-PLUG-PLAY-3-PHASE-CONVERTER-INVERTER-LATHE-MILLING/172965267619?hash=item28458888a3:g:AUAAAOSwvfZZ~woN

There you are now. Stick up a few pictures when you're all set up. Workspaces are grand projects in and of themselves!

ojored · 14-11-2017 10:08pm

Thanks JayZeus - will the 5hp digital converter be suitable for the 360amp mig welder and say the 100amp plasma cutter?
I'll put up some photos when I get things sorted, I need to do a lot of thinking and rearranging first. It's been 25yrs since I did any lathe or milling work, looking forward to it.

14-11-2017 10:29pm

I overlooked the welder and to be honest I don't know how suitable it would be to use the digital converter. Best give the converter manufacturer a call yourself and discuss it with them. You won't be the first to ask it and you'd be better getting the answer and reassurance from them directly.

Barry Flannery · 16-06-2018 8:19pm

Ojored,

Just wondering if you have sorted out your 3-Phase supply issue?

I recently cleared out my own Digital Phase converter and am selling it now here - https://www.donedeal.ie/tools-for-sale/10hp-3-phase-converter-phase-perfect-pt-330/18948245

It's officially "10hp" but actually rated for about 12 kVA. Most important it will run a mix of loads like a welder and milling machine simultaneously.

Regards,

Barry

Best option for 3 phase

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