Is three phase really a benefit for our use ?

[Steve Rozmiarek]

Three phase on a jointer or tablesaw is pretty much no benefit. rotary converters have no real advantage over single phase.
VFDs allow slow start and variable speed of three phase motors but you need one for each machine. A three phase motor should last a lifetime since it has no capacitors or switches to go bad.
Bill D

Bill, there are benefits on a saw and jointer, the braking is nice on both if you use a VFD (like Matt said). Another benefit of VFD three phase on a saw is the ability to change blade speed when changing sizes. VFD can also move between machines, I have one with a wired plug in and out that allows simple moving. Works for the drill press and the lathe.

As for three phase power into your building, that is a great benefit. As others have said, it opens up a whole new level of machinery availability without having to have the extra costs of VFD or converters. I have a welding/fab shop, three phase welders usually have much better duty cycles. Right now, there is a really expensive Miller 400 amp machine with 100% duty cycle available locally, for ridiculously cheap. The little plant it's in is just buying new machines, nothing wrong with it. Great to have access to that sort of thing if you need it.

[Phillip Gregory]

The amount of benefit of 3 phase equipment over single phase largely depends on the piece of equipment.

In general, 3 phase equipment tends to sell for less on the used market and to boot almost all of the larger/better equipment is 3 phase. You nearly always get a better piece of equipment for less on the used market if it's 3 phase as many people do not want to deal with phase conversion. All of my used equipment is 3 phase for those reasons.

If you are deciding between otherwise similar pieces of equipment (such as buying a new single-phase vs. 3 phase piece of equipment), the benefits of 3 phase equipment largely lie in if variable speed control and/or braking using a VFD would be beneficial. Drill presses and lathes greatly benefit from variable speeds, and bandsaws and anything direct drive without a mechanical brake greatly benefits as the VFD can brake the tool very much faster than it spins down by itself. Belt driven machinery designed to run at a single speed such as a jointer, planer, or tablesaw don't benefit much from being 3 phase with everything else being equal as they don't take long to stop. 3 phase motors are simpler than single-phase motors but a single-phase motor is simpler than a 3 phase motor and a phase converter of some fashion. A capacitor-start, capacitor-run single phase motor also has similar power curves as a typical design B 3 phase motor. The 3 phase motor isn't any more efficient once you also include the phase conversion inefficiency into the mix.

[Mike Heidrick]

If you have to ask, it probably won't for you. Most of what 3ph I run and plan to run does not come in 1ph.

[Rod Sheridan]

Hi Bob, no it's not beneficial.

That said, sometimes a used machine is such a bargain, or a machine is only available in 3 phase, so we wind up with one.

In most cases a VFD will be the least costly solution to the problem on a one off basis.

In Canada, a majority of 3 phase equipment is 600 volts, that's not allowed to be distributed in a residential setting so you have to add a VFD and a transformer to the machine. In that case I usually suggest changing to a single phase motor or a 208 volt 3 phase motor.......Regards, Rod.

[Jeff Heath]

In an industrial setting, with 3 phase supplied service, 3 phase is, by far, the best option.

That's not what this thread is about.

For woodworking machinery in a home shop setting, supplied by either a vfd or a RPC, the benefit of 3 phase motors is not so much the 3 phase itself, but the machine it's powering. Industrial machines were built of a quality that is much better than the typical hobby shop machines being purchased new today. No comparison. 3 phase is very nice to have for a lathe, as controlling it with a VFD for speed control is a very nice feature to have. Many of the new ww lathes like Oneway have this feature built in, but you pay thousands of dollars for those new. A vintage industrial lathe, like Oliver, Wadkin, etc.... can be purchased for a fraction of the money, wired to a VFD for speed control for a couple hundred bucks, and you will have a very nice lathe that is, in many instances, a few thousand pounds for stability and vibration dampening. My Oliver patternmakers lathe does NOT walk across the floor when I turn it on.

Not relevant to many users here, but where 3 phase also shines over single phase is with high precision bearings and machinery that requires them. If you're running an overarm/pin router, or a big shaper with expensive Abec 7 or 9 bearings inside, the 3 phase motor supplying the power is much smoother, for a better finish, than a single phase motor with a start capacitor. Where you can really tell the difference is with metalworking machinery, like a precision metal lathe or mill, where the quality of finish is measurable vs. the same machine powered by a single phase motor. The rougher running single phase motor can be seen in lack of quality in the finish of the metal.

Overall, I personally seek out 3 phase machinery, and replace single phase motors on all my machines with 3 phase. Drill presses are a fine example, where the 3 phase motor is just smoother. A drill press, 3 phase motor, with a VFD to control it is a very nice tool to have in your arsenal if you're doing a lot of work with it.

[jack forsberg]

the benefit to any machine with the VFD is motor control. some say no use on a table saw but i say what if you want to add a sanding disk? in some cases putting the blade in backwards and changing rotation let you make some cuts from the back of the saw. sure these are not conventional cut and one needs to know what there doing but if you are modifying your machines then you most likely have the chops. here i am running a drill press at 10,000 RPM as an over head pin router

https://www.instagram.com/p/BjqC8g9AKq8/



switch gear is a big reason to have a VFD and that is why so many with 3 phase line power in the shop use them . Motor control . They are also cleaner than 3 phase line power and are often mandated by the utility to reduce surge at start up on hard start machines . lastly 3 phase is not limited in HP single phase is .

you can run these with your I phone now and it be the control board for thing like the dust collator . So if you want machines with touch screen then the VDF is ideal

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switch gear on my Wadkin RS pattern makers Lathe

https://www.instagram.com/p/BjSDyIdAtud/

[Chris Parks]

VFD's will offer a simpler alternative when they are networked and can be controlled by a application on either a tablet or a PC. I can't see why a tablet application has not been used, it just makes sense to me.

[Patrick Irish]

I put a VFD on my 5hp 3ph planer. Was hesitant cuz I bought the cheap huyuang brand. Almost went with a rpcbut space and too small a panel.

Love the VFD. I just need to wire in a toggle on off switch soon. It’s wired where I use the start stop on it and just unplug it when done using the planer. It shares my dryer outlet.

[Robert Hayward]

After reading all the comments I think 3 phase really does have a benefit over single phase. Motor control.

While my new jointer is the first machine I have owned that required 3 phase to power it up I have two other machines that have factory built in VFD's. A Powermatic 3520b and a Nova Voyager drill press. I would not want either one of these machines if they did not have reversing and variable speed. Motor control is key to using both of these woodworking machines.

Bob

[Keith Mombourquette]

I'm new to these parts, but have been reading the forum for a long time. One of the reasons that I finally joined was so that I could add my 2 cents worth to Robert's post. I just finished converting a very old Union Graduate lathe from 1HP single phase to 2 HP 3 phase with a VFD in order to get control over the motor. I also bought my VFD from Jack Forsberg, and had the same telephone help getting set up and running from Matt. I have to say that this was a delightful experience overall. My lathe is like a new machine with infinite speed control. I will probably never change a pulley again.

Keith

[Robert Hayward]

My lathe is like a new machine with infinite speed control. I will probably never change a pulley again.
Keith

Welcome to the forum. I am with you on the pulley changing. I could not imagine going back to a lathe or a drill press that did not have a knob to dial in the speed I want.

[Matt Mattingley]

Thanks guys. I’m always willing to help out anybody. There is so much confusion in the market of RPCs, VFD‘s, static phase converter’s , phase perfect.... and what is a perfect solution for certain situations. I don’t mind walking anyone or helping anyone through the best solution needed. Most often for small shops VFD‘s are a great solution. They have gentle start and breaking that work absolutely brilliant with lathes and drill presses. For complicated shops with multiple voltage requirements above 300 V a RPC or PP are beneficial. A PP is restricted to 30 hp. A PP is a shop digitally runned complete source. A RPC is A complete source as well which is almost bulletproof but now has its drawbacks. If a person is requiring more than three phase converter’s shops the large RPC, PP or multiple VFD‘s bar the solution. Anyone in this situation needs to weigh out the pros and cons. I am here to only give advice to suit your personal situation... and I don’t mind giving you a call.

If you want to build your own RPC using scrap or recycled parts. I don’t even mind helping you here!

The fact that I require three phase in my shop is because my Lathe Harrison , table saw PK , air compressor 5 hp three-phase, JTA, Do-All, Start-rite, Bridgeport, cylindrical grinder.... and a few other machines woodworking and metal. Pick my brain any day the week.