3 phase power

[Robot]

Hi everybody,

I'm struggling to find the answers I'd like regarding 3 phase power for some machinery I plan to purchase quite soon, specifically my first jointer. For the short term I'll only have access to 'normal' power, and once I move I'm still not sure what power supply any garage/shop might have anyway. Power might actually dictate what machinery I buy.

Question One - Are there 'adapters' or 'converters' that convert normal to 3 phase power in any house so I could purchase a more serious jointer. Are these the things I see for sale on ebay for around $1000? Is there a cheaper option if the 3 phase jointer wasn't 'that big'?

Question Two - On the bold assumption my eventual new place has a garage workshop (even my wife wants one for me, so its looking promising actually), what is required to get 3 phase power to the shop in terms of effort & cost?Or do people run these converter things in most cases still?

Question Three - Do I really need 3 phase tools or am i just getting ahead of myself here, and should be able to get by without needing the biggest/most powerful of everything (I would like to do some larger furniture like tables if that puts things in context?)

Appreciate any comments, I'm a little green with regards to all this. Apologies if this isn't the correct area to put this question also!

Cheers
Robot

[jhovel]

Hi!
You will find that in most cases a Variable Frequency Device (VFD or VSD) is a LOT cheaper than getting 3-phase power connected.
Prices start at about $130 for a 3HP machine and go up from there. You should figure on a separate VFD for each 3-phase machine.
There are distinct advantages in using a VFD that are not immediately obvious to someone starting out to explore bigger machines:
As the name suggests, these little boxes not only proved 3-phase power, but also variable frewuncy = variable machine speed. That is from 0rpm to (depending on the motor construction) twice the rated motor speed.
They also have a 'ramp up' and 'ramp down' operation, which means the start gently without 'dimming the lights' when they start and much gentler on the equipment, and slow down gently or more quickly than 'switching off'.
There are a couple of caveats however: firstly you still need the full power for the machines in terms of the wiring to the shed/garage. Adding up the power of all the machines you are likely to run at the same time (dust extractor, power feeds etc) as well as the machine itself will give you an idea how big the wiring and circuit breakers needs to be. Secondly, installation of bigger than 15A powerpoints is very expensive, therefore you should factor in having bigger than 3 or 4HP machines having their VFDs connceted by a sparky as fixed or hard wired in.
Lastly, these devices (except for one known exception) do not change the voltage to 440V, but provide 240V 3-phase power. That means the motors need to be configuired for 240V DELTA connection. Most modern motors have that option in their terminal box, older motors may be hardwired for 440V STAR connection - but they too can be reconfigured.
Lastly, many motors bigger than about 7HP or so may be 'Star-Delta starting', which means they cannot be successfully run at 240V - other than expecting only about 2/3 or less rated power. THey stil run OK though.

Lots of info on this forum on all these issues and solutions. Search for 'VFD', 'Huanyang' and 'motor rewinders'.
Help is always here!

[BobL]

Joe has provided a very good answer but let me answer your questions perhaps a more specifically and with some other points of view.

Question One - Are there 'adapters' or 'converters' that convert normal to 3 phase power in any house so I could purchase a more serious jointer. Are these the things I see for sale on ebay for around $1000? Is there a cheaper option if the 3 phase jointer wasn't 'that big'?

You have several options with the 3Phase jointer.

The VFD route which Joe has detailed the many benefits of is one. I also like them and have 4 VFDs on machines in my shed and a couple of VFDs that I use for testing motors. I'm finding 3 phase plus VFD is so versatile that I replaced the single phase motors on my WW lathe and drill press with a used 3 phase motor. However it is not all beer and skittles.

VFDs can be a cheaper route than having 3 phase power installed BUT this really only applies if you are capable and prepared to perform the VFD installation. They are most definitely NOT "plug and play" and were not talking 12V here and it is life threatening stuff if it is not down correctly. If you have to call in a sparky to fit VFDs to a couple of machines it may cost you almost as much as installing 3 phase power. Not many domestic sparkies are VFD aware and will often go the simplest as opposed to the cheapest route, Some of them will even call in a specialist to do it because they are simply not comfortable or experienced in doing it. If the 3 phase motor is Y connected it will need to be converted to ∆ connection but sparkies will not do this so it will need to be sent to a motor rewinder which just adds to the cost.

A friend of mine was quoted more than $1000 to fit a VFD to a lathe because the sparky insisted on using an expensive ($600) VFD he was familiar with and would not use an ebay cheapie (understandably he does after all have to guarantee the installation).

Last week I purchased a used 3 Phase compressor from a sparkie who was selling it because he was moving to a house where there was no 3 phase power. When I asked him if he had considered using a VFD he said he had heard of them but even he said that it was going to be cheaper for him to install 3 phase power to the house than use a VFD. He also reckoned that VFDs were too expensive (he thought a VFD cost about $1000) and was not prepared to do the motor conversion himself (even though is does not need it). I said no more about it as I could see he was not comfortable discussing it with someone who knew something about it

You haven't said how big the motor on the jointer is but if it is not more than 4HP you could replace the three phase motor with a single phase motor. A 3HP motor usually requires a 15A circuit and a 4HP a 20A circuit. If you don't have these in your shed you will have to get these run anyway even when using a single phase. Changing the motor is not always as easy as it seems either. The motor mounting points and pulley shaft/diameter needs to match. This can be a PITA and unless you have access to serious MW gear and the experience then this is not always easy.

Like Joe says you need to determine your total power use at any one time and ensure that your shed circuits can support this.
For me its a case of running a welder and compressor (both 15A) at the same time, OR a 3HP dust extractor and a 3HP table saw at the same time. I already had a 20A line to my shed but I ended up installing a second 45A as I also have an air conditioner.

Question Two - On the bold assumption my eventual new place has a garage workshop (even my wife wants one for me, so its looking promising actually), what is required to get 3 phase power to the shop in terms of effort & cost?Or do people run these converter things in most cases still?

Well firstly your property must have 3 phase power. Installation cost can be quite high depending on how far you are from the power outside your property and you'll need a new meter and house distribution box. 5 Years ago I was quoted $3000 to install 3 phase power and our power poles are 10m away from our house. I would hate to think what it would cost now.
Then you will also need a 3Phase line from the house to the shed and most likely a second distribution box in the shed.

Question Three - Do I really need 3 phase tools or am i just getting ahead of myself here, and should be able to get by without needing the biggest/most powerful of everything (I would like to do some larger furniture like tables if that puts things in context?)

This is a bit like how long is a piece of string. You could sharpen your WW blades on a rock and use a hand drill for everything if you wanted to. Even Viking banquet hall tables can be made completely with hand tools if you really want to. 3 Phase is only needed if you want to access machines with motor power requirements above 4HP. There are many benefits that joe has outlined Used 3 phase machinery is usually more robust and has more life left in it than single phase machinery

[justonething]

You can convert single phase to 3 phase using a rotary phase converter. They are on ebay. How to hook them up is another story. See the discussion on renovate forum. http://www.renovateforum.com/f195/ro...15/#post935653

[Poppa]

I have a couple of points to mention that others (with their excellent answers) haven't. It is often possible to pick up second hand 3 phase tools more cheaply than their single phase relations because most blokes don't have 3 phase. This can make up the difference between getting 3 phase installed and not. I had 3 phase installed in my workshop at our previous house. Cost about $4500, which included a separate power board, 2 x 20A sockets, 2 x 15A sockets, and about 20 x 10A sockets around the room. While this seemed like a lot of money I think it was worth it, and I am getting the same done in my new workshop at our new house. Both houses had 3 phase coming in off the street, which made the work easy, but the sparkie I use is not cheap (and does not do anything on the cheap). Since I'm useless at electricity stuff I don't do it as I have ambitions to live longer. I've bought a second hand 3 phase Hammer combination machine and an old 3 phase Waldown (sp?) drill press. They are the only 3 phase machines I have at this stage, but I do go to a few auctions, and the nice thing is if I see something that is good value and I can upgrade my current kit I can buy it no matter what power it needs. But I would also say that as an amateur woodworker you could get the full range of power tools and machinery all with single phase power and you'd never have to look at 3 phase. As others have said you need to get enough power to the workshop in total no matter which type of power you opt for. Single phase is certainly easier and less expensive from a purely power perspective.

[zelk]

3 phase power could also be used for other things like a 3 ph home ducted airconditioner, that was the logic I used to justify it, my wife did not and could not object.
zelk

[BobL]

3 phase power could also be used for other things like a 3 ph home ducted airconditioner, that was the logic I used to justify it, my wife did not and could not object.
zelk

Or in the case of a BIL, a spa!

It would have come in real handy for us as recently we installed a 7kW cook top.

[Enfield Guy]

When I built my shed and had the power connected the sparky had 3 phase connected to my home from the pole in the street. I told the power supplier it was so I could install air con, didn't mention the shed. The power co came and did the change, new cable from street and new insulators on the building and the additional meters for nothing. Sparky then ran a cable to the shed and installed the outlets required.

The cost of 3 phase outlets is quite steep, plan on $100 and outlet. Cable is quite expensive as well, but the advantages outweigh the cost in my view. The additional cost to me of having 3 phase (3 circuits) rather than just single phase worked out to about $600 of the $3000 I spent on electrical fit out.

Go 3 phase if you can.

Cheers

[Albert]

Hi,

I was in your situation not long ago, I know a few electrician and electrical engineer from my work, the consensus is that, get the 3 phase power if you really need it. Otherwise just single phase.

there is a guy in Cambridge NZ who does these converter for single to 3 phase, they are not cheap and they have a limit of 10hp. A 10hp unit is between 3000-4000NZD. My phase installation + electrician cost is slightly more, so why bother.