Any electricians in here? 3-phase question...

[Funkmasta]

OK, so I am looking to buy some equipment for the shop, but the machine I am trying to purchase is 480 3phase... and I only have 220 single phase.

I know there are phase converters, but I think it will only convert to 220 3 phase, and not sure what that will do with that (and other) machinery.

I am not expecting to be in my current building for more than another 12 months, so I would really like to start investing in quality machinery from the get-go.

Possible?

By the way... I AM electrically retarded, so lets use kindergarten vocabulary...

:)

thanks!

[nkell09]

I have heard the power company have to do a drop for 3 phase 480? Is this true?

[ivo316]

You did not say how many hp's the motor has.

I am not an electrician, But I tried some fancy things in the past, I advise you to call your electricity company and get the 480 volt 3 phase lead, they'll charge you for it, but to convert to three phase and then use a transformer to increase voltage from 220 to 480 will cost you a lot of money in hardware, and the load on the 220 lead will be BIIIG (if it could be done, which i'm not sure).

to size your transformer take horsepower * 746 to get total volt amp estimate ( for example - 5 horse * 746 = 3730 volt amps) 3.73 kva for a full running speed current. for start up current multiply this by 2.5 for a total of 9325 Volt amps. so a 10 kva transformer would be what you need to not overwork it on the startup current if the motor is 5 hp.

utilize three individual transformers if you can (may be cheaper)

Electrical - Transformers Westinghouse 10 KVA Transformer Afton CAD $400.00

Check this link to make your own 3 phase converter:

http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

Or see a table with prices here:

http://www.phaseconverter.com/

Good Luck

[Funkmasta]

3 hp's

[ivo316]

3 * 746 = 2238 volt amps

5.57 Kva, that will be a 6 kva transformer

And while you are operating, check your main power line (the one that goes from the pole to your shop/house to see if it overheats, that really depends on the gage the electricity company useds there.

Good luck

[Rigmaster]

I'm definitely NOT an electrician, or even close. But I have done some research into this and learned alot.

I saw 3 phase vs single phase power described like this- (which made the most sense to me). Think of the work you want to do with the electricity as a big metal spike that you want to drive into the ground- the electricity is represented as a guy (or guys) with big ass sledgehammers doing the work. Single phase 220v power is like one guy with a big ass hammer hitting the spike, 3 phase 220v power is like 3 guys hitting the spike one after the other.

Anyway- to answer your question, you CAN run 3 phase off of single phase- but it's a rig at best and damaging to equipment at worst. You would probably want to use a rotary converter (vs. a box with some capacitors, etc). A rotary converter is basically a 3 phase motor that you wire up to start and run without any load, then take the 3 leads from this motor and connect it to the 3 phase motor on your machinery to run the machinery. This is generally considered to be the best way to convert to 3 phase- but you sort of have to know what you're doing for it to work correctly.


What sort of machinery are you considering that's 3 phase 480?? Must be something serious- a milling machine perhaps?

I have some more 3 phase conversion info if you're interested- lemme know.


Bret.

[BDSax]

my company is doing a dry cleaning place and they had to buy a 3 phase convertor. i know it wasnt cheap at all. you probably better off getting the equipment single phase. unless you do decide to refeed with 3 phase, but then your talked mega bucks. remember, wire isnt cheap anymore.