Newest Toy/Creation

[desperado]

I finally got 3 phase power in the garage at home. I did some swapping and ended up with a large 3 phase motor and abunch of parts that I turned into a rotary phase convertor. What it does for those that have never heard of one is it takes regular single phase 220 and makes it 3 phase by using the windings in the running motor and the run capacitors that are connected between the motor leads. This makes it possible to run most any 3 phase piece of equipment that has less than a 40 amp draw (which is set by the size of the motor). I also ended up with a rather large 3 phase industral MIG welder with seperate wire feeder. (For some idea of the size, the power supply weighs 600 lbs and the seperate wire feeder is as big as as a run of the mill 85 amp wire feed welder that is self contained). While this may sound a bit overboard, consider that I can run high dollar industrial equipment that is all but given away at auctions because most people see that it's 3 phase and turn away from it because it will not run on standard household power.

[Guest 1sweet3.4]

nurr. laymans terms he can weld your kid's bike frame. and two hundred of your friends bikes. NIce welder man. graemlins/thumb.gif

[Science Abuse]

AEP thanks you tongue.gif

[Lustalbert]

I wondered why my clock was flashing this morning.

[desperado]

Originally posted by The Stig:

AEP thanks you tongue.gif

Na AEP hates me. I looked at setting 3 phase at the shop at one point. $5000 to put it in and $200 minimum monthly bill for the electric.

 

I will say that the startup is a bit intense, and dims the garage lights pretty bad, but I still have some values to tune on the start capacitors. But the idle current draw is about 3 amps, so having the motor running draws less than my refigriator. Now once I start welding with it and running other stuff, it's current draw will increase the load for sure. But because it's 3 phase load and not single phase it doesn't draw as much, that's why factories use 3 phase.

 

You have to remember that with single phase, the power drops to 0 twice per cycle. With 3 phase there is always power because there is always a voltage potential between 2 of the 3 legs at all times. It's sort of hard to explain without being able to graph it out. But if you know what a sine wave looks like from either trig class or from any electronics work you have done. Single phase 220 (actually its 2 phase but no one calls it that) are two sine waves 180 degrees out of phase of each other. Each phase is 110 volts RMS.

So as the phases hit their peak RMS voltage the potential between then is 220 Volts RMS. But when they cross the 0 voltage line there is NO potential (voltage) between them. With no voltage there is no current flow and what ever you are driving freespins (motor) With 3 phase there are 3 lines or phases that are at 220 volts RMS between any two phases at peak and becasue the three phases are at 120 degrees of phase shift and not 180 there is always voltage potential between two of the three phases at all times and hence the ability for current flow which is the torque so to speak of electicity.

 

It's like conpairing a two stroke motor and a 4 stroke motor. A two stroke motor fires every time the piston reaches the top of the cylinder. It has less pumping loss and only has to be kept spinning until the piston reaches the top again.

A four stroke fires once every other time the piston hits TDC, it make one full revolution on stored power in the flywheel using only inertia to carry it around. This would be considered single phase basically.

 

Now while you can't create something from nothing, you cal lie to what measures the power you are using. The meter on the side of my house is designed for single phase, and that's what it reads. Because I am shifting the phases around, the single phase current is lagging behind the voltage changes as it alternates. The meter is designed to read single phase and not 3 phase, so for it to read correctly it beed the voltage potential and the current to be the same, not the current lagging behind the voltage. It's called meter droop. Newer meters take it into account and will measure it, but the older spin type meters don't have that ability. The other think I am doing is placing alot of capacitance across the 220. Most EVERYTHING that you have at home is a inductance type load. That goes from a record player to an electric furnace. The capacitance cancels the inductance on my side of the meter and again will balance the load. Here again, it's not expected so it's not designed to spin faster.

 

Now I don't want anyone to get some idea that I am stealing power here. That ain't the case. I am just converting it into a more efficent power that due to the increased efficency I use less than if I went out and bought the same size motors or welders that were single phase and ran them off the standard household electric.

[desperado]

Originally posted by the voyeur-ager kid:

nurr. laymans terms he can weld your kid's bike frame. and two hundred of your friends bikes. NIce welder man. graemlins/thumb.gif

First thanks,,, Second, yeah you sort of have it right. I have the big MIG welder that i can use right now. But if I find a three phase CNC mill or lathe, I only need to haul it home and connect it to the 3 phase power, instead of theneed to replace all the motors with single phase one and in the case of a CNC unit, deal with any of the power supplies that are 3 phase that run the numerical control. And like I said before, stuff like this gets sold at auctions for pennies on the 100 dollar because most people can't just take it home and plug it into the wall.

[Black ITR Guy]

sweet tits for getting expensive toos for cheap.

[old dirty bastard]

Hillbilly know how you gotta love it

[Lustalbert]

3 phase is da shit.

actualy had to wire some of it while in iraq, god damn some of the wiring I had to straigten out. one tent was wired up on 2 hot leads or the 3 phase so all the 220 fixtures where getting 440. Bright as fuck for about 2 minutes till they started blowing up.

[desperado]

Well, so much for trusting someone elses sugjestion. The guy that sold me the start capacitors sold me ones that were rated for 165 volts. Said they would be fine. I sent smoke signals with it tonight. The caps cooked, and they ALWAYS smoke to beat hell when you fry them.

 

So I got some parts on order that are of the correct voltage (250) and I will get it back together and running soon.

[Mensan]

May I see a drawing of your system, and how you hooked it up please? You can PM it if you like.

[Mark1647545493]

How big is this setup? Got any pics of it?

[RS69]

Sounds excellent. 3 Phase stuff is so cheap compared to single phase(CNC, welders, industrial equipment,etc). My dad's shop has a set up similar to what you have done.