How do you get 3-Phase power to a residential workshop

[Alan Lightstone]

Can you get 3-phase power directly from the utility company, or must you use a rotary phase converter or a VFD?

Does a VFD replace a rotary phase converter (does it convert 1-phase to 3-phase), or do you just use it to control the power of already delivered 3-phase power?

[Martin Wasner]

Depends on proximity and how much you want to spend getting it there. Residential use will be very low, so if they'll do it, it's going to cost a fortune.

I use a fair amount of juice and had to go 1200 feet, I budgeted $20,000 but ended up paying less than $5000 with a transformer

[Martin Wasner]

And yes, a vfd can make 3 phase from single phase

[Alan Lightstone]

And yes, a vfd can make 3 phase from single phase

From my quick research, it seems like vfd's max out at about 1.5HP. I will need 220V 3-Phase for a few 5HP 3-phase motors (jointer, planer, table saw). They shouldn't be running at the same time.

What's the best approach for that? A Rotary Phase Converter, A Digital Phase Converter like the Phase Perfect model? Another approach?

[Dan Friedrichs]

You can get larger VFDs. If you look on ebay, you can find 5HP single-phase-input VFDs for ~$180.

[Bill Dufour]

For big tools like those you can power them from one VFD running one motor at a time. Not too hard if they are the same amp draw motors if you do not care about the instant reverse, variable speed, braking or low speed start up being custom tuned for each tool.
That extra stuff is really only needed for a drill press or maybe a sander or lathe.
Bill

[Alan Lightstone]

Interesting. The VFDs even the 10HP ones on eBay (I will need a 10HP one for a 5HP motor, right?)are much less expensive than I expected.

Are they difficult to program. I'm concerned as the units are Chinese, inexpensive, and may not have awesome English instructions.

[Bruce Wrenn]

VFD's are available in the 6000 HP range (think railroad locomotives,) but you can't afford them. A rotary converter is the best way to go for multiple machines. It's basically a three phase motor, with a method of bring it up to speed. Generated third leg is usually a little lower than other two legs.

[John Gulick]

VFD's are available in the 6000 HP range (think railroad locomotives,) but you can't afford them. A rotary converter is the best way to go for multiple machines. It's basically a three phase motor, with a method of bring it up to speed. Generated third leg is usually a little lower than other two legs.

+1 We have gone this route for several months and for less than $500 have a great system

[Jeff Ramsey]

Interesting. The VFDs even the 10HP ones on eBay (I will need a 10HP one for a 5HP motor, right?)are much less expensive than I expected.

Are they difficult to program. I'm concerned as the units are Chinese, inexpensive, and may not have awesome English instructions.

I have two Lapond VFDs and their technical support was excellent when I was configuring them.

[Malcolm McLeod]

Interesting. The VFDs even the 10HP ones on eBay (I will need a 10HP one for a 5HP motor, right?)are much less expensive than I expected.

Are they difficult to program. I'm concerned as the units are Chinese, inexpensive, and may not have awesome English instructions.

Alan - The 10Hp Huanyang unit (auction #181949861664, I think?) is rated for an input of 34A (at 220-250V) and for either 1-phase or 3-phase operation. So, each input leg can handle 34A. This would easily carry the 28 FL Amps input needed by a 5Hp motor fed by a 230V/1-phase service (15.5A. output).

It would be a stretch for this VFD to handle a 7.5 Hp motor needing 40 FL amps (1-phase) input, but only 22A out. You'd have to baby it. The input side of the VFD is the limiting factor.

For programming, there are lots of parameters to sort thru, but 90% are probably just fine with the factory preset values.

NOT PROMOTING THIS UNIT - - JUST ANALYZING THE SPECS.

[David Kumm]

Does anyone have info regarding the Huanyang vfds and if they have improved? Over at the Practical Machinist forum which gets into some pretty detailed and complicated electrics, the Huanyang vfds are prohibited from discussions because the moderators believe them to be so poorly built. No first hand knowledge, just wondering. Dave

[jack forsberg]

Does anyone have info regarding the Huanyang vfds and if they have improved? Over at the Practical Machinist forum which gets into some pretty detailed and complicated electrics, the Huanyang vfds are prohibited from discussions because the moderators believe them to be so poorly built. No first hand knowledge, just wondering. Dave

there position is they are not there support

[Matt Day]

Alan, lots of information on VFD's on here so please do some homework, though of course we're here to help.

Factorymation products are solid and have great manuals and great customer support. You'll pay a bit more than eBay models from overseas, but if you're not comfortable it may be worth it.

[David Kumm]

You can get into a RPC for 1000-1500, vfds will run 250-400 for each machine and require you to bypass most starters and wire the start stop buttons to the vfd. Not a huge deal but sounds like you don't have a lot of experience with them so you would need some help. Phase Perfect is a close to perfect option but will cost you about 4000. Power will be balanced much better for all sizes of motors. With an RPC the quality of the motor and electrical components will account for the price differences among the brands. Kay and Arco rate their units by the largest motor it will start. Most others rate them by the total hp they will run. A 10 hp Kay is roughly equal to a 20 hp Am Rotary as an example. Important to know that when comparing pricing. You want to slightly oversize them. A 7.5 hp Kay or 15 hp AM Rotary. That size rpc will be best balanced at higher loads but still run small motors. With VFDs pay attention to the output amperage. You need 15+ amps for a 5 hp motor. Some will be rated at 5 hp and some at 10 hp but the output amps are the key. Dave