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pvellenga
02-10-2009, 06:48 PM
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.

SCzEngrgGroup
02-10-2009, 06:54 PM
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
02-10-2009, 07:17 PM
Are you saying I can run 3-phase machines with the VFD? So would a Haas Minimill run using the VFD?

SCzEngrgGroup
02-10-2009, 08:10 PM
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.A/id.198/.f?category=

Regards,
Ray L.

cadmonkey
02-10-2009, 09:23 PM
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
02-10-2009, 09:59 PM
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
02-10-2009, 10:05 PM
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
02-10-2009, 10:34 PM
A Haas MiniMill will run on single phase 240volts and needs a 50amp supply.

EDIT: Had the current requirement wrong.

mc-motorsports
02-10-2009, 10:53 PM
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.

SSN Vet
02-10-2009, 11:19 PM
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
02-11-2009, 09:52 AM
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
02-11-2009, 02:52 PM
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.

pvellenga
02-11-2009, 06:21 PM
THank you for all of the good info. I will look into the rotary phase converter. I would really like to get the Minimill and just finance it out and save some of my capital for cash flow. This will be a tough choice going foward. Again thanks for the help.

Geof
02-11-2009, 06:28 PM
.... I will look into the rotary phase converter. I would really like to get the Minimill....


If you get a Haas MiniMill you do not need a phase convertor.

SSN Vet
02-11-2009, 09:44 PM
http://www.grizzly.com/products/Rotary-Phase-Converter-5-HP/G5844

here's one place to get one....

they sell them up to 20 HP, but they get pricey up at that end

mc-motorsports
02-12-2009, 09:55 PM
If you get a Haas MiniMill you do not need a phase convertor.

Here's a good question.


3 phase power will deliver more torque, granted it's true 3 phase...

Single phase is nice, because you don't need 3 phase...

Rotarty converters generate 3 phase, but at a % of torque of that of true 3 phase...

SO... What is best, in a given situation where you have an option, single phase, or a rotary phase converter that generates what electical engineers call a "wild leg"....

I'm honestly interested to know.

Geof
02-12-2009, 10:47 PM
......SO... What is best, in a given situation where you have an option, single phase, or a rotary phase converter that generates what electical engineers call a "wild leg"....

I'm honestly interested to know.

Have you read other threads about rotary phase converters and/or running CNC machines from 'artificial' three phase?

What I have gleaned from various threads is that a rotary phase converter is fine for running three phase motors. In fact the combination of the phase converter and a three phase motor serves to make the artificial three phase more like real three phase and it works very effectively.

However a CNC machine is not a three phase motor and it is not an inductive load. Various threads have mentioned that running a CNC machine on a simple idler motor based phase converter is questionable and it is better to use a more sophisticated system such as a phase perfect that make better quality artificial three phase.

The more sophisticated systems cost more and it just seems a bit pontless to me to consider running a MiniMill on any form of artificial three phase when the standard machine will run on single phase. Certainly the maximum motor power is slightly reduced but how many people run their machine at maximum spindle power all the time? It is not a serious problem to limit yourself to a maximum spindle load of 75%.

millman52
05-10-2009, 05:32 PM
I run a shop daily with 7 different RPC's All are home built but 1 most are ballanced.

I agree with Geof if the machine in question will run on 220V single phase power as well as 3 phase power. Why bother with any sort of conversion at all.

Even if I had other 3 phase equipment I wanted to run & needed a converter. I'd still run the mill single phase. That is unless part of the features of the machine aren't available on single phase power.

The beauty of RPC over VFD is they are dirt simple to operate & maintain once you understand what's going on. A VFD although fairly simple to hook up & use. If you have a problem with the VFD you most likely are going to buy another one or send yours in for repair. Anothe sapect of VFD that no one seems to ever talk about. Sure they are capable of making a standard machine variable speed. They also reduce the rated HP of a motor as the speed dropps off.

roadking
07-09-2009, 08:31 AM
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.
I have just purchased and installed a PhasePerfect digital phase converter. Because the electric coming from this unit is delta balanced (phase to phase, not phase to ground), one leg (T3) has higher voltage than the others. I am concerned that this generated leg may be harmful to my Fanuc controlled VMC. Do I need to place this generated leg on any particular terminal when I complete the instyallation? I'd appriciate any comments you have.

123CNC
07-09-2009, 10:47 PM
I have just purchased and installed a PhasePerfect digital phase converter. Because the electric coming from this unit is delta balanced (phase to phase, not phase to ground), one leg (T3) has higher voltage than the others. I am concerned that this generated leg may be harmful to my Fanuc controlled VMC. Do I need to place this generated leg on any particular terminal when I complete the instyallation? I'd appriciate any comments you have.

First I would recommend giving PhasePerfect a call as CNC is one of their advertised 'perfect' applications.

You would need to look to your VMC specs and or FANUC controller series spec on wiring and voltage requirements and tolerance, be it phase to phase or phase to ground. Some three phase VFDs do monitor the supply voltage and will alarm or shutdown if the supply voltage is out of range.

Third option would be to review the wiring diagrams or trace your wiring and determine which of the one or two legs of supplied three phase serves the controller and low voltage control wiring and make sure either T1/T2 and not your wild or high T3 leg is used to supply these loads. In other words make sure T3 is only used for full three phase loads like your VFD/Spindle and coolant pump, etc.

OF course first and best recommendation, call Phase Perfect.

123CNC
07-11-2009, 02:03 PM
This may be more helpful for your FANUC request.


"If the three-phase equipment has 120V phase-to-neutral circuits that cannot be isolated and connected to either leg 1 or leg 2, the output of the phase converter must be passed through a 240V delta to 120/208V wye isolation transformer. This transformer will establish ground and neutral at equal distance from all three legs and deliver the power in a wye configuration.
This is especially important when operating some newer CNC machines that have certain Fanuc or Siemens controls. These controls handle regenerative power from the spindle motor by putting the regenerative power back onto the line utilizing a phase-to-neutral connection on all three legs. If these machines are powered by a phase converter with delta configured power, the regen circuit on the leg manufactured by the phase converter will operate at a voltage that is too high. An isolation transformer must be used to convert the power from delta to wye configuration."

Quoted from http://www.phaseconverterinfo.com/phaseconverter_deltawye.htm

123CNC
07-11-2009, 02:15 PM
Phase Perfect manual (for DP series) confirms they operate in delta mode, so if yoou need a wye supply, you'll need to use an isolation transformer.

From http://www.phaseperfect.com/techinfo.htm

"The three-phase output is delta configured. While the phase-to-phase voltages

are equal, the phase-to-ground voltages are not equal. When T1 and T2 to
ground voltage is 120V, T3 to ground voltage will be approximately 208V. For
three-phase loads that are designed for delta connection, the load derives its
voltage phase-to-phase, so the phase-to-ground voltage should not affect the
operation of the equipment. If the connected load has a neutral connection and
requires wye configured power, the output of the phase converter must be
passed through a delta-to-wye isolation transformer before connection to the
load."

Al_The_Man
07-11-2009, 04:40 PM
If you look at the Phase Perfect manual, they show the two 240 1phase lines passed directly through, same as an RPC does and just creates the third phase electronically.
http://www.phaseperfect.com/files/all%20models%20manual.pdf
Al.

bsdphk
07-11-2009, 06:00 PM
If you look at the Phase Perfect manual, they show the two 240 1phase lines passed directly through, same as an RPC does and just creates the third phase electronically.
http://www.phaseperfect.com/files/all%20models%20manual.pdf
Al.

There is one parameter more than just voltage, amperage and number of phases, and that is the phase angle.

In a true 3-phase system, the three phases are 120 degree apart.

This is incredibly smart for motors, (and generators, which is why we do it) since it gives uniform rotating field, which means maximum torque for minimum power input (or vice versa for generators).

The trick the Phase Perfect does, mentioned above, will not (always) give you 120 degree phase separation, in particular not if the input phase is 2x120VAC 180 degree.

But it works well enough to start a motor and keep it rotating, but it will not get you the same torque or efficiency as a 3x120 degree supply.

Instead of that crude trick, do what others have also mentioned earlier:

The simplest and perfectly workable solution, is to use a variable frequency drive and just leave it set at whatever corresponds to the voltage and frequency you want.

A real VFD takes whatever power input you feed it, creates two high voltage DC buses, while emitting a minimum of electrical noise, often less than the motor would, back into the power system.

From the dual DC busses, it creates three phase VAC, 120 degree apart, at whatever voltage and frequency you ask from it.

Any motor you have with a starting capacitor in your shop, provided it is of nontrivial size, will benefit from a VFD in terms of efficiency and torque.

And of course, you get continuously variable speed on your lathe, drillpress, grinder etc. as a nice side effect.

Som VFD's even have the option of DC bus input, so you could even run your CNC directly from your Photovoltaic HV battery system, without the detour through the mains inverter :-)

I wont recommend any brands, because I live over here in 3x400V/50Hz Denmark where 3phase installations are the standard, so you probably could neither locate, buy or use them anyway in the USA.

Poul-Henning

PS: If your electrician can not explain in terms of AC current and magnetic fields why the motor rotates and why the VFD changes the RPM, get another one.

Al_The_Man
07-11-2009, 06:07 PM
The trick the Phase Perfect does, mentioned above, will not (always) give you 120 degree phase separation, in particular not if the input phase is 2x120VAC 180 degree.

.

What would you describe the phase angle as being, and also with a RPC?? :)
Al.

bsdphk
07-11-2009, 06:44 PM
What would you describe the phase angle as being, and also with a RPC?? :)
Al.

With a rotatinge power converter, you get 3x120 degree, unless the designer smoked something.

Basically, a RPC is a motor, running however you hook it up, and an 3-phase generator which does what a 3-phase generator does: generate 3 equally spaced phases: 360 degree / 3 = 120 degrees.

The point about the RPC is that it is technology we have had for 100+ years, and you can combine the motor and generator any way you want: 110V/60Hz motor, 220V/50Hz generator.

Or even 500V/400Hz. Sailors will recognize that one for "shore power converters".

The entire electrical trainsystem i Germany used to be run on 1000V 16+2/3 Hz (= 50/3 Hz), thanks to some really huge RPC all over the country.

However, compared to a VFD, a RPC is a monster.

Not only in terms of size and weight, but you also waste between 20 and 50 % of the input power to noise and heat due to all the mechnics and electromagnetics involved.

A 7.5kW RPC is about a foot and a half cube, weighs in at 75 kg and will start a motor between 3 and 7.5 HP, depending on the mechanical load.

The output frequency, and thus RPM of your tool, depends on the input frequency (an issue if you ever run on emergency power from a diesel generator) and the stability depends on the mechanical inertia of the rotating system (big heavy == better, but more losses, noise, heat etc).

In comparison, a 7.5kW VFD weighs just short of 4 kg, mounts on the wall and probably does not even have an internal fan, just some cooling fins on the outside, because the efficiency is in the 92-95% range.

It will start any motor up to 10 HP at any mechanical load, because it can do so by ramping up the frequency. This is obviously better for the motor and bearings as well.

The frequency is always whatever the electronics dictate, provided there is enough input power and voltage and frequency to the motor can be adjusted
separately.

A VFD is also very good at spotting motor trouble, overheating, shorts etc, and shut down before you need a new motor.

There has been no sane reason to invest in an RPC to run a motor for the last ten years.

Running electronics off an VFD is mostly not an issue, provided frequency & voltage is acceptable to the powersupplies.

But do check the noise/EMI/EMC specs on the secondary side of the VFD, some of the cheap ones rely on the motor to not care.

I belive that as a rule of thumb, any VFD than can meet FCC/CE rules without using shielded cable to the motor should be fine for electronics.

Poul-Henning

Al_The_Man
07-11-2009, 07:02 PM
The trick the Phase Perfect does, mentioned above, will not (always) give you 120 degree phase separation, in particular not if the input phase is 2x120VAC 180 degree.
.

I guess I had to ask!

But my question was aimed at the 'In particular if the input is 2x120vac 180 degree'??
The inclusion of VFD did not really enter the picture.
Al.

bsdphk
07-12-2009, 04:47 AM
I guess I had to ask!

But my question was aimed at the 'In particular if the input is 2x120vac 180 degree'??


My guess is that you get 180-90-90, which still amounts to a turning magnetic field in the motor, just not a uniform turning magnetic field.

You should ask them.

Poul-Henning

Al_The_Man
07-12-2009, 10:39 AM
The RPC I built as described by Fitch Williams around 15yrs ago, like most RPC's the single phase 240 is carried through as two of the phases, the Phase perfect does the same thing but produces the third phase electronically.
The RPC just produces a third phase shifted relative to the other two.
Here is a scope wave form of the one I built showing a phase angle of 120deg phase angle between the three.
The introduction of the third element has moved the vector reference point.
Al.

bsdphk
07-12-2009, 10:58 AM
The introduction of the third element has moved the vector reference point.
Al.

Hehe, shows my european bias: I pressumed the electrical code had banned a "dancing zero" like that.

Yes, that certainly will work, the key details is that the zero is not brought out, and the load assumed to be overwhelmingly symmetrical.

I wouldn't dare put any kind of electronics on it though, as the peak voltage to ground reference can become quite significant that way.

Which brings me back to something I wondered about when this thread started:

Are you sure the CNC we were originally talking about really needed 3P power ?

If it has built-in electronic motor control, it likely has a common HVDC bus for that, and the 3P inlet may simply be to keep the cable diameter and amperage down...

Poul-Henning