Dangle_kt
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| posted on 10/11/16 at 10:00 AM |
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CNC Mill in garage - 3 phase options?
I have a domestic UK power supply in my garage.
Just snapped up an educational HAAS CNC mill for a good price. It has 3 phase power requirements, which is a pain but after some small amount of
research not impossible to resolve.
I'd welcome some real world experience - electricity has always been a complete black bag for me, so I'd welcome a steer.
I have read of VFD - they seem cheap enough but I have read they can only drive the spindle directly, not the whole machine?
I have also read of phase converters, which seem to do a good job and can power the whole machine.
The thing I am not clear on (apart from if VFD can be my sole source of power) is the HP requirements.
Is there a way of working it out? There is a plate on it I have a photo of:
voltage 360-480
phase 3
hertz 50/60
full load 20 amps
largest load 20 amps
can any of those numbers be used to work back to a spindle horse power?
Thanks folks
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David Jenkins
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| posted on 10/11/16 at 10:11 AM |
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I have a 3-phase Colchester lathe that I run on a phase converter. There are issues - the converter has to be adjusted so that the lathe motor will
start and run properly, but this means that the coolant pump won't run properly on its own as the settings are all wrong. I could run the
coolant pump when the main motor is running, but things would go wrong if I stopped the main motor without stopping the pump. In your case, you may
not be able to run the bed movement motors without the main motor running.
BUT - there is a way to sort it out - get a bigger converter, then have another large 3-phase motor connected permanently to its output. This
'pilot motor' doesn't drive anything but it holds the converter output to a steady 3-phase, so that other motors can be turned on
and off without any worries. You will need the usual switchgear to turn the pilot motor on and off, of course. This advice was given to me by the
supplier of my converter, Transwave, who always seemed happy to give advice, especially if they think you might buy one of their units!
[Edited on 10/11/16 by David Jenkins]
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Dangle_kt
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| posted on 10/11/16 at 10:16 AM |
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Think this is them?
IS that thing on the back the motor you refer to?
TRANSWAVE Rotary Converter 15hp/11kW - Single to 3 Three Phase 240v to 415v
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Wadders
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| posted on 10/11/16 at 10:42 AM |
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I built a 3hp rotary phase converter to run my first lathe, plans are freely available on the web, it cost less than £50 and worked great, the slave
motor needs to be bigger than the motor in your machine. I later had a workshop for a while with 3 phase, the lathe didn't run any better on
true 3 phase.
If you ask on the practical machinist forum, someone will know the HP of your Haas, assuming you know which model it is. Going by the 20 amp per phase
data plate, I would hazard a guess of 15hp plus.
My current 3hp Colchester lathe is running from a VFD. The advantages are you get variable speed control etc, however the VFD has to be wired direct
to the motor, so no good if the machine has multiple motors. Also you have to bypass all the machines current wiring, so highly unlikely to be any
good for a CNC machine.
I've just acquired a Beaver conventional turret mill which has 3 motors, the spindle motor is 3hp, so I'm going to build a 5hp rotary
converter.
Stick some pics up, would like to see the beast.
[Edited on 10/11/16 by Wadders]
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richardm6994
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| posted on 10/11/16 at 10:51 AM |
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I bought a 3phase bridgport in April and after much reading about phase converters at the time, I went for one of these;
2 HP DIGITAL 240V to 415V 3 PHASE INVERTER CONVERTER LATHE MILL DRILL
I also bought the forward/reverse speed control 'add-on' that they can supply for an extra £50.
The whole set-up was really easy to install and has been running fine (3/4 days a week) since April.
But as said above, it has to be wired directly to the machine motor and not through the machine's control box (my table power feeds have a
separate single phase supply)
I decided against the rotary converters because of power consumption - running a big slave motor just to run another motor wasn't appealing to
me given how much use the machine is getting.
[Edited on 10/11/16 by richardm6994]
[Edited on 10/11/16 by richardm6994]
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dinosaurjuice
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| posted on 10/11/16 at 10:54 AM |
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quote:
Originally posted by Dangle_kt
voltage 360-480
phase 3
hertz 50/60
full load 20 amps
largest load 20 amps
can any of those numbers be used to work back to a spindle horse power?
Thanks folks
Is that the power just for the spindle motor?
If so, and based on a few power factor and efficiency assumptions it will be about 15 hp.
if i was converting it to single phase i would run the spindle motor from a VFD and convert the control/stepper/function side of the machines to work
from single phase (its probably DC already anyway)
interesting project 
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big_wasa
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| posted on 10/11/16 at 11:32 AM |
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Dont buy more than one converter thinking you can run each motor independent. Each unit has an earth leakage close to what your Rcd in your consumer
unit can handle. And two just trip it out.
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Dangle_kt
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| posted on 10/11/16 at 11:44 AM |
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Thanks guys - So I am hearing that a VFD is not an option, as there are at least 4 motors on the cnc lathe (maybe 5 if the coolant pump is included)
and would be far too messy to run each of a VFD.
The rotary phase converter is an option, and can even be DIY built (If I wish to kill myself and the rest of lancashire due to my inept electrickery
understanding) and it seems likely I will require around 15HP unit (which cost over £1k new...  )
Do these need to be installed? Do they run off a special spur from the consumer unit, or just a plug? Really doubt it's just a plug! 
Seems my bargain wasn't THAT good a bargain, but I'm still happy. I will track down the forum you mention and do some more research.
The idea of converting it to single phase sounds promising, but that as you say would be a much longer term project!
In terms of photos, just look at the ebay advert. I'm not precious about you guys knowing the prices, I've been on here long enough to
know someone will always have got a better price than I managed!
HAAS VF0 CNC MILLING MACHINE VMC
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Dangle_kt
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| posted on 10/11/16 at 12:48 PM |
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well I am currently kicking myself.
The machine is 7 ft tall, my garage roof is 8ft, but the up and over door is about 6ft.
What a plonker.
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AJC
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| posted on 10/11/16 at 01:01 PM |
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You might have a bit of upwards travel on the quill too.
Looks like a bargain to me.
I haven't a clue on the electrical side of things, but I might be able to help you on the programming side, when you get going, as we use
similar machines at work.
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hughpinder
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| posted on 10/11/16 at 02:03 PM |
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Can your single phase/240 V supply cope - UK standard domestic supplies vary between 60 and 100A? You will need a 68A supply for a DOL start on a
15HP motor, (21A at 415V), assuming no loss on conversion.
I assume this is actually a number of lower powered motors rather than 1 at that power, but you can use this table to look up the phase current and
work out the effect of them all starting at once.
See http://www.sprecherschuh.com/download/sscdn7500F/index/hp-volts-fla_chart_v206.pdf
You will struggle to get a VFD with single phase input -> 3 pase o/p at more that 2.2kw (3hp) rating at any sort of reasonable price too. In fact
you don't often see single phase motors for a rotary converter that are more than 4kw/5hp. Probably cheapest will be a small car engine from a
scrapyard and a used 3 phase electric motor combination acting as a rotary converter and just run that when you need to use the machine (maybe a
phase converter just to allow power up of the programmer while setting it up so you don't have to run it all the time). Sorry if that is not
what you need to hear!
Regards
Hugh
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Dangle_kt
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| posted on 10/11/16 at 02:04 PM |
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quote:
Originally posted by AJC
You might have a bit of upwards travel on the quill too.
Looks like a bargain to me.
I haven't a clue on the electrical side of things, but I might be able to help you on the programming side, when you get going, as we use
similar machines at work.
Thanks - hoping to use fusion 360 CAD/CAM, and the installed drip feed card to send the code as the on board memory on these is small
You might get a message in 2 years when I finally get it set up
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Dangle_kt
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| posted on 10/11/16 at 02:08 PM |
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quote:
Originally posted by hughpinder
Can your single phase/240 V supply cope - UK standard domestic supplies vary between 60 and 100A? You will need a 68A supply for a DOL start on a
15HP motor, (21A at 415V), assuming no loss on conversion.
I assume this is actually a number of lower powered motors rather than 1 at that power, but you can use this table to look up the phase current and
work out the effect of them all starting at once.
See http://www.sprecherschuh.com/download/sscdn7500F/index/hp-volts-fla_chart_v206.pdf
You will struggle to get a VFD with single phase input -> 3 pase o/p at more that 2.2kw (3hp) rating at any sort of reasonable price too. In fact
you don't often see single phase motors for a rotary converter that are more than 4kw/5hp. Probably cheapest will be a small car engine from a
scrapyard and a used 3 phase electric motor combination acting as a rotary converter and just run that when you need to use the machine (maybe a
phase converter just to allow power up of the programmer while setting it up so you don't have to run it all the time). Sorry if that is not
what you need to hear!
Regards
Hugh
No idea - going to get my family member who is a spark onto it to figure it all out.
It can be done as I have read of a fair few domestic garages with HAAS vf0 - vf4 running, and they are bigger.
I've given myself a learning curve like everest with this I can tell, but I'm hoping it will be worth it when I can make some shiny parts!
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winchman
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| posted on 10/11/16 at 03:51 PM |
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Speak to George at Newton Tessla in Warrington before you give up hope, nice bloke and very cheap on price as he buys lots of older stock nothing up
with it just last years model
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Wadders
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| posted on 10/11/16 at 05:11 PM |
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quote:
Originally posted by hughpinder
Can your single phase/240 V supply cope - UK standard domestic supplies vary between 60 and 100A? You will need a 68A supply for a DOL start on a
15HP motor, (21A at 415V), assuming no loss on conversion.
I assume this is actually a number of lower powered motors rather than 1 at that power, but you can use this table to look up the phase current and
work out the effect of them all starting at once.
See http://www.sprecherschuh.com/download/sscdn7500F/index/hp-volts-fla_chart_v206.pdf
You will struggle to get a VFD with single phase input -> 3 pase o/p at more that 2.2kw (3hp) rating at any sort of reasonable price too. In fact
you don't often see single phase motors for a rotary converter that are more than 4kw/5hp. Probably cheapest will be a small car engine from a
scrapyard and a used 3 phase electric motor combination acting as a rotary converter and just run that when you need to use the machine (maybe a
phase converter just to allow power up of the programmer while setting it up so you don't have to run it all the time). Sorry if that is not
what you need to hear!
Regards
Hugh
The idler motor on a rotary converter is 3 phase not single, so readily available in pretty much any HP, however your comments on starting current are
relevant.
Smaller RPC's are capacitor start, but when you get up in to the realms of 15HP plus, it's common to have a smaller capacitor start donkey
motor to mechanically spin up the bigger one........more cost and complication.
IIRC the 3HP RPC pulled around 6 amps per phase when running a 1.5 HP lathe, and it's worth noting that if the main spindle motor is indeed
15HP, to run at full power will probably need a 20HP phase converter or larger.
Quite a challenge.......
[Edited on 10/11/16 by Wadders]
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David Jenkins
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| posted on 10/11/16 at 06:06 PM |
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quote:
Originally posted by Dangle_kt
Think this is them?
IS that thing on the back the motor you refer to?
TRANSWAVE Rotary Converter 15hp/11kW - Single to 3 Three Phase 240v to 415v
Sounds like it - do a Google on them, then give them a ring - they'll tell you what you will need (they were very helpful when I spoke to them
at a show). I emphasis that they'll guide you to what you need, not the most expensive.
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DanP
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| posted on 10/11/16 at 07:49 PM |
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2K!!! what a bargain! I paid more than that for a wabeco bench top CNC second hand!
Thats the deal of the century, the tool changer is probably worth more than 2K!
Well done and good luck, Fuion 360 is awesome, i use it for my CNC mill and lathe, just wish I had a tool changer for the mill.
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Wadders
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| posted on 10/11/16 at 10:02 PM |
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Worth asking a few questions here.....
http://www.cnczone.com/forums/
http://madmodder.net
http://www.practicalmachinist.com
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Dangle_kt
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| posted on 11/11/16 at 09:49 AM |
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thanks guys - really helpful.
My relative has told me how to find out how much amps are coming into the property. He said he'd imagine my house is 100amps and if it is
running a 15hp phase converter is doable, though he rightly suggested it might be cheaper just to rent a small unit with 3phase in the short term.
must resist!
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David Jenkins
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| posted on 11/11/16 at 11:04 AM |
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Does your mains supply come underground or overground?
The reason I ask is that a friend of mine wanted to do a similar thing, so he asked his power company for a quote to get 3-phase run to his house.
After asking him why he wanted it (a LOT of questions!) they pointed out that the poles outside his house carried 3-phase around the neighbourhood
(they share the phases around the houses to spread the load).
He ended up paying for the installation of the 2 extra wires to the house/workshop, termination equipment & so on, plus labour costs, and it still
ended up cheaper than a large phase converter - and he got 'proper 3-phase' as well (converters will only give 'almost proper
3-phase', even when properly matched to the motor).
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Dangle_kt
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| posted on 13/11/16 at 08:27 PM |
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underground, is it the power company I pay the bills to that I contact or someone else? I'm never very clear how utilities work, after all if
you can swap who provides electricity with a few mouse clicks there mustn't be a direct link between that and the cables in the road?
Thanks for the tip!
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Dangle_kt
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| posted on 14/11/16 at 01:43 PM |
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Just an update incase this is useful, I have found the company I need to contact is called the Distribution network operator, for my area they are
called electricity north west.
I called them up, they have sent me a very simple form, I fill it in, send it back and they get a quotation to me for the work - seems pretty straight
forward.
Just need to get a site plan drawn to send with it, and someone to do the house side of the install (they will only take the install to the kerb edge.
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David Jenkins
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| posted on 14/11/16 at 03:57 PM |
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You can save a large amount of money by digging your own trench from the kerb to the garage - that's one thing you can do yourself that
doesn't require qualifications and/or certification!
My supply is underground - it was WAY too expensive for me to get connected, and that was 10 or 15 years ago!
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Dangle_kt
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| posted on 15/11/16 at 10:14 AM |
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it's all of about 3 foot, my garage and electric meter is practically on the kerb side but I'll dig it myself, good shout
I got a quote of £2,270.00 for the phase converter, so it's worth finding out about 3 phase install costs.
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