View Full Version : 1 phase Vs 3 Phase power what is the difference?????


KustomKoncepts
11-15-2007, 11:07 PM
Please help I have to know what is the difference between 1 phase and 3 phase?

If I have a 1 phase wired shop and the router I am looting at says it is a 3 phase spindle. how will this work in my shop? I did read on a web search that ther are 1 to 3 phase converter boxes that I can put in but how much will that run me?

thank for all your help

carvinmarvin
11-15-2007, 11:30 PM
I bought one of these "excitech" routers before they changed the name.. These are also known as as xhyc but they changed the name.

I learned the hard way that these routers they are selling have different requirements for electrical in europe and china than we have here in the U.S. It cost me almost $6,000 dollars to convert our building to 3phase after spending $2,000 on a phase converter only to find out it wouldnt work with the chinese wiring. They tell you 220 but its 250 and the amperage requiremnets are way off.. they cant provide an electrical schematic or a wire diagram or anything.

mxtras
11-16-2007, 12:51 AM
"Single" phase is one phase of three phase power. The phase references the peaks and valleys of the sine wave which is inherent with A/C power. If you have three phase power, you have three legs which are constantly changing in relation to eachother. Perhaps a quick Google search can shed some more light on the subject.

A VFD (Variable Frequency Drive) is a good way to get three phase from single phase. The price depends on the horsepower of the motor you are trying to run. They will run you around $150 for a unit that is suited for a smaller horsepower (1HP - 1.5HP) motor.

Do a search on this site for VFD. You should find a few hundred threads. Many of these threads have sources for purchasing such a device. They are simple to hook up and give you decent control flexibility but have some limitations.

Scott

KustomKoncepts
11-16-2007, 01:25 PM
OK I may have jumped the gun here. I assumed I have 1 phase because all the 220 equipement in my shop say that on there labels. I had a electrition buddy here and he said that is only 1 phase equipement and does not say what the shop was wired for.

he took of the electrical panel and there is 4 wires coming in.

3 hot and one nutral

he said I have 120/240v 3 phase 60HZ

does this seem right. but he said that I actually only have 208V power. will this CH-cnc run as it is asking for 220V power?

Al_The_Man
11-16-2007, 04:03 PM
See if there is a tolerance rating, most equipment is rated for ±10% so you should be OK.
Al.

rc-cellar
11-16-2007, 04:55 PM
120/208V is the standard for 3-phase power in the US... you're good to go.

Like Al said, motors have a wide voltage tolerance. Your 220v equipment is now running just fine on 208v.

KustomKoncepts
11-16-2007, 05:07 PM
I know the IR air compressor and Lincoln welder actually say 230V when I know I am giving them 208. hopfully this electical problem is not a broblem at all. I just have to make sure you know. thanks all. later

mxtras
11-17-2007, 01:41 PM
You need to identify what it is that you have. It sounds like Red leg, or High leg 208.

Scott

Al_The_Man
11-17-2007, 02:21 PM
It sounds like Red leg, or High leg 208.

Scott

He mentions he has true 3phase at 208v, not a converter.
I think he is concerned about his single phase 240v loads running off two phases 208v.
Al.

KustomKoncepts
11-17-2007, 02:33 PM
I think I have if figured out.

My shop is wired at

120/208 3 phase 60Hz

there are 4 big wires coming into the inside panel.

my friend said are all 120v but 3 phase varies in voltage and it is like a pirmid taking 120 from this line plus 120 from that line and some fancy math later after running through a risistor I get 208 apperation in the shop. even though the welder, aircompressor and paint booth all say 220V on them they fall in the +- 10% opperating range. so I think I am ready to go sorry for all the 1phase 3 phase confusion.

Al_The_Man
11-17-2007, 02:41 PM
If you have a 4 wire grounded neutral, then most likely you have what is known as 3 phase Star (Wye) with centre point neutral ground, I don't think you have any resistors in there!
The 120 is between one phase and neutral, & the 208 is between any two of the three phase windings.
Al.

KustomKoncepts
11-17-2007, 03:53 PM
Yes that sounds like what he explained. he drew a thing that looked like the flux compasitor on back to the future. nutral in the middle and 3 120v lines going to it. and the voltage between 2 lines was 208 v

Thank you all for the info.

BobF
11-17-2007, 10:34 PM
Your original post said the machine has a 3 phase spindle. Many machines use a 3 phase drive with VFD to give variable speed. Most VFDs will accept input of single phase or 3 phase and give 3 phase output. If this is the case with your machine, you could wire it either way and it would work.
The drive on my lathe works this way. I only have single phase in the house. The VFD makes 3 phase out of it. The only difference is that it draws a little more current in single phase.