3 phase power - what's needed?

I'm exploring the possibility of building my own shop and would like to have both single and three phase 440 power available. Not being an electrician, but very much being budget minded, I'd like to see about obtaining used transformers etc... I'll be picking the brains of a couple electricians, but I'd like to have a good basic understanding of what's needed so I can at least speak the language. I'm headed to amazon.com to see about a good book or two, but thought I'd toss a line in the well-stocked pond known as The Wreck. Thanks.
JP
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wrote:

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First you'll need to move to an industrial area. Three-phase power is not usually available in residential areas. Three-phase is not the sort of thing you keep lying around just in case you need it someday. When your shop gets big enough to need 3-phase, it won't be a hobby anymore.
DonkeyHody "In theory, theory and practice are the same, but in practice they are not."
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Jay Pique wrote: > I'm exploring the possibility of building my own shop and would like > to have both single and three phase 440 power available.
In a residential area?
Forget it.
It would be easier to find a chicken with lips.
In a light commercial area?
Maybe.
Probably be easier to find 208Y/120.
Heavy industrial?
No problem.
Get 480Y277 if you can.
Lew
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Hi Lew:
In addition to your list, add
Rural: It depends on whether you are. If there are larger dairies and many grain legs around and you are between them and the substation with 3phase on the power poles on your road it may not be too hard. If you aren't then it's either impossible of exceedingly expensive.
---------------- And another observation:
For the budget minded, as others have pointed out -- parts are generally more expensive. It may cost more to have it brought in. Used machines tend to be less expensive. For my area (YMMV): The monthly "facility charge" or "base charge"-- what you pay to have a meter and be hooked to the grid is about double for 3ph vs 1ph where we are. Cost per kWH is about 10-12% less with 3ph. When I pushed my numbers around, the monthly check to the utility company is nearly invariant. So the real issue for me is that boards and breakers can be more expensive. Get an electrician friend and watch the flea-bay -- you can occasionally find used panels stuffed full of breakers and occasionally they go cheap. Buy carefully, used panels can be junk.
hex -30-
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centers, but only for specific systems that require it. They only require it so that they can obtain very clean input voltages - something like IBM's Regatta systems that require input 2 3 phase 60 amp taps. But basically you'll need 3 hot bars in your box - if you can get that then you'll be paying so much for electricity the local utilities commission will put your name on an honorary plaque.
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if three phase is not available in your area you would need to put in a rotory phase converter to generate the third leg. size of converter depends on the use demand. ross www.highislandexport.com
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check out www.faderotary.info scroll down to (single to 3 phase converter) and it will tell you how to build a converter. ross www.highislandexport.com
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motors.
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No - I'm not joking! I should have said that I work full time as a woodworker and that I'm planning to make my living from this DreamShop.
Probably I'd be better off over on woodweb, but I've had great success here with a variety of different topics.
JP
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480 3 phase gives you the most choices for any usage. It is the service we try to put in all our schools. I think we have 3 schools left with 208. The big service uses the smallest wire, the most efficient equipment loads, and complete flexibility to derive all services.
You will need a step down transformer for conventional usage. Only you and your utility company can decide how doable for your location both in availability and minimum purchase of power. Only you and your electrician can work out the cost differences for switch gear.
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Jay:
If you have overhead wires on poles, go outside and count the wires. If there are 3 wires running from pole to pole, or sometimes 6 or multiples of 3 all on insulators, you probably have 3 phase power on the street. If your supply is fed underground, find a ground mounted transformer box and read the label on it, it will tell you the phases and voltages of the feed and supply.
If you have 2 wires, or one wire and a ground/neutral wire you don't have 3 phase available. Remember don't count the telephone cables nor the cable TV wires by mistake.
I'm

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wrote:

Check with your serving utility and see what is available. Unless your in an area it is offered you'll have to look into phase converters. If you don't have any three phase tools then its probably not worth the expense to put it in. Also unless you can show the utility that you will consume enough power to cover the cost of installing 3 phase you will probably find the cost more then you'll want to spend.
Mike M
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I have to say that it is possible to put in. Actually depending on where you live, you might have high voltage lines at the pole already. But in many areas 3 phase 480/277 services are forbidden to a residence. Unless you are a business, the cost of the equipment alone is quite high. The panelboard alone will start at roughly $800 and then start throwing in the 112kva transformer to go to a 208/120 200a service add another $2000-$3000, the load center for 200a 208/120 add another $400, the breakers to go in it around another $150.
And since this is new, forget using a standard transformer as now energy efficient transformers are required per EPACT. EE's are virtually non-exsistant in the used market. When the new rules went into effect at the begining of this year, used EE's became the hottest thing. Sometimes going for prices near new one's were.
Put the 3 phase in when you need it. It isn't economical to have it just because.
Allen

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You need to head over to rec.crafts.metalworking, seriously These guys can help you out on your quest. 440 volt 3 phase would be a stretch on a household utility supply, but 208/240 3 phase is not a real big deal. If you have some ability, and can scrounge a suitable 3 phase motor, and some various electrical components you can whip up a phase converter yourself. Greg
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Phase converters
Occasionally the advantages of three-phase motors make it worthwhile to convert single-phase power to three phase. Small customers, such as residential or farm properties may not have access to a three-phase supply, or may not want to pay for the extra cost of a three-phase service, but may still wish to use three-phase equipment. Such converters may also allow the frequency to be varied allowing speed control. Some locomotives are moving to multi-phase motors driven by such systems even though the incoming supply to a locomotive is nearly always either DC or single phase AC.
Because single-phase power is interrupted at each moment that the voltage crosses zero but three-phase delivers power continuously, any such converter must have a way to store energy for the necessary fraction of a second.
One method for using three-phase equipment on a single-phase supply is with a rotary phase converter, essentially a three-phase motor with special starting arrangements and power factor correction that produces balanced three-phase power. When properly designed these rotary converters can allow satisfactory operation of three-phase equipment such as machine tools on a single phase supply. In such a device, the energy storage is performed by the mechanical inertia (flywheel effect) of the rotating components.
A second method that was popular in the 1940s and 50s was a method that was called the transformer method. In that time period capacitors were more expensive relative to transformers. So an autotransformer was used to apply more power through fewer capacitors. This method performs well and does have supporters, even today. The usage of the name transformer method separated it from another common method, the static converter, as both methods have no moving parts, which separates them from the rotary converters.
Another method often attempted is with a device referred to as a static phase converter. This method of running three phase equipment is commonly attempted with motor loads though it only supplies power and can cause the motor loads to run hot and in some cases overheat. This method will not work when any circuitry is involved such as CNC devices, or in induction and rectifier type loads.
Some devices are made which create an imitation three-phase from three- wire single phase supplies. This is done by creating a third "subphase" between the two live conductors, resulting in a phase separation of 180 90 = 90. Many three-phase devices will run on this configuration, but at lower efficiency.
Variable-frequency drives (also known as solid-state inverters) are used to provide precise speed and torque control of three phase motors. Some models can be powered by a single phase supply. VFDs work by converting the supply voltage to DC and converting the DC to a suitable three phase source for the motor.
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Step 1: contact your electric utility and find out "what is available" at the location you are considering building at.     this may significantly restrict your options.
Used transformers _are_ available. 'surplussales.com' has a 45KVA unit listed on their website input 480V 3-phase delta, output 208Y/120. for the ridiculous price of a little over $2/pound. Weight 360lbs price $795
<http://www.surplussales.com/Transformers/IsolationXmers-3.html bottom-left of the page
bottom-right shows a new 50KVA unit, at $2395. This one is documented as having voltage-adjust taps, that can adjust for high/low supply voltage.
If you're serious about 440v the Acme unit looks like something to grab _now_ even if it is 'build later' for the shop. :)
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Jay Im in the UK and what I do is either buy a single phase motor for the 3 phase machine or recently I have started to buy an inverter. I have a friend who is an electrician can install it for me. This allows it also to be variable speed as well as being able to stop the machine in under 10 seconds as reqired by the Health and Safety Executive. This is actually a lot cheaper than fitting a DC injection brake. The other reason is that sometimes motors are specially made for a machine manufacturer and the single phase motor to buy from them (if they are still in business) is a lot more expensive than converting it with an inverter. I also have another mate who supplies motors and I can get cheap motors from him. Second hand 3 phase machinery is a lot cheaper here and is always a better build quality than the tin plate imported rubbish that is sold everywhere nowadays and if I had more space in my workshop would buy more. So far I have converted a big bandsaw, spindle moulder and a Dewalt ras which is 35 year old but as good as the day it came out of the factory. It also has a cross cut capacity of 39 inches at 4 inches depth of cut which is 15 wider than what Dewalt make at present and not a piece of tin plate in sight!

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wrote:

I completely agree with you. And that's a nice RAS. Thanks to you and everyone for your input.
JP
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