Emach 250R

Morning guys, Wells its been a while. And my choice of building a machine turned into buying one, the simple reason at the time, i felt i lacked some skills needed. Welding and no on hands skills work with metal.

But over the past few years ive learned to weld, and practice alot with metals. The machine i got was an emach250r, i paid very little for it, under £1000 as it was in many many bits, and was sold for spare or repair. This gave me a great opportunity to learn and build up a machine, so to speak.

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The machine works runs, and has treated me well so far, but and a big but i reached the limits of the machine, and started finding many faults with the way it had been designed. so i set about rebuilding it again, but to higher standards. first up was a complete rebuild of the gantry. Im am about finished, just some tweeks to the z to do.

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I also build a new frame for the table to go on, the original being 3 i shaped legs caused way to much vibration when cutting and on some stock, caused a ruff edge to the cuts.

Now skip forward a few months, and again im at a cross roads....

Well covid has hit my business hard, with no help from our government. So i have to let my workshop go. Income is not covering costs ect.

But im not one to give up, so my plan is to move back to my original workshop (short term), till things get back to normall.

I would love to keep my cnc, and get it setup in the home workshop, i have space. But what i dont have is 3 phase power.

Now ive looked at my machine control box, and motors ect, and done believe i need 3 phase ?

The only 3 phase power needed was for the suction bed, this i never used as i never got a pump for it. (was on the todo list)

below ive attached some pics,

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and diagrams ive drawn up.

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Now as i wont be needing the 3 phase output to the vacuum pump, do you think its possible to convert this machine to single phase.

Should add my spindal cutter is a hsd, at/mt 1073-060. only 1.5kw, nema 34 on x and y, nema 24 on z. all driven from motion msd 542's. the hsd spindal cutter is driven from a optidrive invertec e2

Having had a quick look at your diagrams, it does look like you could run this from single phase.
It looks like the 3 phase was only used for the vacuum pump, as the inverter and main transformer use a Live plus Neutral, so should run of 240V just fine.

This was my thinking, and if 100 percent correct, music to my ears. and about the best news ive had this week lol.
what kind of power do you think it needs. 32amp ceeform. 64amp ect. currently my workshop can handle up to 64amps. on the main fuse board. but i do have the abilitty to re run the mains power to workshop upto 125amps.

Now looking at the parts in my machine the schneider lc1k09 004p7 are rates to 230v. should i replace these with the 230v to 240v versions.

You could probably run it off a 13A plug.

Spindle is only 1.5KW (~6A), and I doubt the axis motors (I'm guessing this is a stepper driven machine going by the look of the drivers?) will use much power.
Biggest issue is likely to be any surge current from the initial power up of the transformer and inverter, but any surge can be limited with a suitable surge limiter, but I'd try it with just a normal 13A fuse first. Worst case scenario is you just blow the fuse.

ive just taken a better picture of the control box.

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All wiring to motors switches to machine, have been disconnected ect in this pic.

As for the 230/240V thing, I wouldn't worry.
The chances are anything rated at 230V, will have a wide enough tolerance to work up to 250V in order to meet the official EU mains voltage harmonisation limits.

So if i connect live to l1, neutral to neutral and earth to earth, on the original, inputs. would i need to disconnect the l2 and l3 ect. or leave as is.
And if instead of the 3 phase output to vacuum pump, if i connected a single phase pump, just to the l1 out on the lr2k0321, would this work.

lr2k0321 below the lc1ko9.

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Originally Posted by Ben-bee

So if i connect live to l1, neutral to neutral and earth to earth, on the original, inputs. would i need to disconnect the l2 and l3 ect. or leave as is.
And if instead of the 3 phase output to vacuum pump, if i connected a single phase pump, just to the l1 out on the lr2k0321, would this work.

lr2k0321 below the lc1ko9.

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That should work fine.

However you'd have to check the current limits of the LR2K0321, as a single phase pump is likely to need more current, so may exceed the current limit. The worst case scenario is you need change the protection device, and if you go too big on the vacuum, you may even have to upgrade the other contactors.
What you may find is an easier option, is to add another inverter to run a vacuum pump, as 3 phase vacuum pumps will be more common/cheaper.

good idea, great stuff. Thanks for you help M_C, once i get the machine inplace, ill get some pics posted ect.

As far as I can see from your diagrams, only vacuum pump that is NOT USED is connected to all 3 phases. Everything else is single phase.

Your ears will be delighted :)

Glad to hear this. The machine is a bit of a war horse, looks ugly, performs like a dog, but I love it lol. Glad it can with more tlc move to its new home in my home workshop.

Edit:deleted post because browser didn't show me other replys which answered your questions.