Build Thread- 3-phase power

[pvellenga]

Hey guys!

How much would it cost me to get 3-phase power run to a pole building where a Haas Mini Mill could be sitting. I have been looking at smaller single phase mill but I like the idea of a little larger machine with an ATC. Do any of you have that type of set-up? Can I even get 3-phase power at a residence or does it have to be zoned for light industrial to even get 3-phase power. I know this is probably in the wrong part of the forums but thought I would ask if any of you guys have done it or were about to do it.

[HimyKabibble]

Originally Posted by pvellenga Hey guys! How much would it cost me to get 3-phase power run to a pole building where a Haas Mini Mill could be sitting. I have been looking at smaller single phase mill but I like the idea of a little larger machine with an ATC. Do any of you have that type of set-up? Can I even get 3-phase power at a residence or does it have to be zoned for light industrial to even get 3-phase power. I know this is probably in the wrong part of the forums but thought I would ask if any of you guys have done it or were about to do it.

WAY the hell more thant it'd be worth. Unless it's more than about 3HP, the quick and easy thing to do is buy a VFD (Variable Frequency Drive). It'll allow you to run a 3-phase motor from a single-phase supply, and give you variable speed up to at least 2X the rated motor speed to boot. Your other option would be a rotary phase converter, but that'd cost more, and won't give you variable speed.

Regards,
Ray L.

[pvellenga]

Are you saying I can run 3-phase machines with the VFD? So would a Haas Minimill run using the VFD?

[HimyKabibble]

Originally Posted by pvellenga Are you saying I can run 3-phase machines with the VFD? So would a Haas Minimill run using the VFD?

Yes. The VFD runs on either single-phase or 3-phase, and can generate variable frequency three phase out, at different voltages. So, for instance, you can run a 220V 3-phase motor from a 110V single phase line. I run my 220V 3HP 3-phase knee mill from a 220V single-phase line, and I can run it up to 120Hz, which doubles the motor speed, or down to about 10Hz. Which means fewer pulley changes. Mine is a Westinghouse/TECO FM-50, which cost about $200:

http://www.factorymation.com/s.nl/it...8/.f?category=

Regards,
Ray L.

[cadmonkey]

One thing to note about the difference between a VFD and a Rotary converter - the rotary converter is intended to supply machine(s) (and its/their internal components) designed to run on 3 phase, whereas a VFD is intended to drive a motor - that's not saying it can't do the whole machine, but if anything inside is dependent on 3 phases you'd have to rewire possibly a significant amount of the machine to allow those portions to run on the single phase supply unless the VFD is set on the exact phasing of line generated 3 phase.

Hope that makes sense.

Greg

[escott76]

Originally Posted by cadmonkey One thing to note about the difference between a VFD and a Rotary converter - the rotary converter is intended to supply machine(s) (and its/their internal components) designed to run on 3 phase, whereas a VFD is intended to drive a motor - that's not saying it can't do the whole machine, but if anything inside is dependent on 3 phases you'd have to rewire possibly a significant amount of the machine to allow those portions to run on the single phase supply unless the VFD is set on the exact phasing of line generated 3 phase. Hope that makes sense. Greg

The HAAS that I wired up (A TM1) would take either single or 3 phase, but it wasn't 3 phase to the motor and single for the rest. The OP might check to see if the minimill was the same. A VFD would not be used to run the whole machine that I am aware of.
It may be difficult to separate wiring in a machine like that as the control may freak if it sees different voltages than it expects. It's one thing to run different power supplies for different components you choose on a retrofit, but the HAAS is already a turnkey, and was designed to operate as such.
Residential 3 phase, if it's even available where you are, is going to be VERY expensive, both to be installed, and in costs per month. I'd look at other options first, as they are almost certainly going to be cheaper.

[cjdavis618]

No question. Go with a cnc rated Rotary Phase converter. They are rated by the HP of the motor and needs to be larger than your HP of the mill.

They run off of 220 Volt single phase power (Like a Dryer, cook stove, etc etc.) and convert the power to 3 Phase 220 (Or other voltage if desired). Basically you turn it on with a switch, it spins up like any other motor and then the 3rd phase is "created" by the circuit being opened when the milling machine (Or other device) is powered on.

A VFD is not something I would want to power a Minimill that has built in controllers and items such as that. Like Cadmonkey said, they are great for powering and controlling motors alone, but a VFD running electronics seems like a disaster waiting to happen. If you set the adjustments correctly on the VFD and never touch them, then it would work. But accidents happen and turning a knob, or hitting the buttons by accident could be a very expensive mistake to the controllers on the machine.

I own 2 RPCs and a VFD so I can speak with some level of experience with this.

[Geof]

A Haas MiniMill will run on single phase 240volts and needs a 50amp supply.

EDIT: Had the current requirement wrong.

[mc-motorsports]

My uncle had a similar situation, he built a shop on his residential property for his custom cabinate business. He uses a few 3 phase machines and called the power company, $12,000, he bought and uses a rotary phase converter.

[Matt McColley]

disclaimer... I'm not an electrician, nor an electrical engineer.

you can run 3 ph induction motors off of single phase power, but you need the third leg to start it. You can do this by wiring up a starting capacitor to give you the 3rd leg. Or you can just or rig up a single phase "jump" motor or even a rip cord to get the 3 ph motor moving and then apply the single phase power to run it. Once going, the 3 ph motor will run at ~3/5 it's rated HP.

You can also use an electric phase invertor to electronically produce the third leg, but these are usually only rated for motors up to a couple HP.

A rotary phase invertor is the cat's meoow, and can run several 3 ph motors at their full rated power. I.E. a 5 HP rotary can run two 3 HP motors. I'm not totally up on the theory, but each driven motor acts to generate some add'l power for the next motor down the line.

In fact a rotary phase invertor is nothing more than a three phase motor with two legs driven off of your 220 single phase. The rig has a starting capacitor circuit to temporarilly generate the third leg and produce torque to spin up the motor. As the motor spins, driven by the two legs, it generates on the third one. As the third leg voltage comes up, it is sensed by a voltage sensing relay that then takes the starting capacitor out of the circuit. The system is "tuned" with run capacitors that get the phase angle between the legs to 120 deg.

If you have access to industrial surplus/scrap, you can make your own rotary phase convertor for short $.

My employer is forever hitting up bankruptcy auctions and because he shows up with a box truck and a maintenance man and some rigging gear, he often brings home the unsold lots for nothin', just because he can immediately take them away. What we don't use we scrap.

I've got a box in the basement with a 7 hp 3 ph motor, a NEMA box and fused isolation switch, all of which cost me zip. The most expensive components for me where the relays, fuses and start capacitor.

Plans for such home builds are readilly had on the net or in old issues of mags like Fine Woodworking. No one will publish this kind of material today for fear of liability and when the topic comes up in the occasional letter to the editor, they'll just respond with the pat "that's dangerous if your not a licensed electrician"

I undertook this project because I also salvaged a robustly built 3 ph 3HP cyclone dust collector. I also had dibs on a solid running 3 ph 3 HP 10" Powermatic table saw and a 14" radial arm saw, but my boss wanted to much for them and I didn't have room to store them untill I got my shop built. So the radial arm saw was scrapped and I was aced out of the table saw by the lead maintenance guy (whom I firmly believe stole it). So my motivation to finish the build waned, but I'm thinking of taking it up again this summer.

The point of all this rambling is that solid used industrial machines with 3 ph motors are very available and sell for less than much weaker single phase home owner stuff. So setting yourself up for 3 ph can really pay off.

A VFD is for running a spindle, not for running the entire machine.

BE WARNED, howerver, that if you do a home build rotary and burn your house down, your insurance company will likely blame you and deny the claim.

As always, prudence is the better part of valor.

called the power company, $12,000

and what's worse, they will likely reclassify you as a commercial account and tripple your electric bill for the same qty. of juice.

[project5k]

i looked into getting 3ph at my home shop when i was first building it, they wanted a massive deposit, in the order of $20k, and then they wanted like $18k to do the install, not to mention that the minimum on the account was $200 per month.

I decided if i ever needed 3 ph, i'd come up with a rotary converter or something, or just change out whatever motor there was on the machine to a single phase motor....

I dont need 3 ph that darn bad.
I know its more efficient, but nahh, i'll skip it for now.

[123CNC]

If you really need 3-phase, don't like the utility companies price, and not crazy about the added noise of a rotary phase converter (and proper sizing, or multiples for efficient load handling) you may want to consider PhasePerfect (others?).

Essentially a fixed output vfd/vsd. The beauty is no worry of changing any settings, the software is not user accessible. They are not cheap, but cheaper than utility runs (when available) and quieter than an RPC. The quiet is nice when your spindle is idle during setup, etc. A PhasePerfect inverter will serve as a three phase mains to a machine, leaving the machine cabinet wiring untouched with respect to control voltages.