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

  1. #1
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    How do you get 3-Phase power to a residential workshop

    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?
    You did WHAT???!!!??? Well, that makes you a Moron.
    We at %&^* Healthcare consider that a pre-existing condition.

  2. #2
    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

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

  4. #4
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    Quote Originally Posted by Martin Wasner View Post
    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?
    You did WHAT???!!!??? Well, that makes you a Moron.
    We at %&^* Healthcare consider that a pre-existing condition.

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

  6. #6
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    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

  7. #7
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    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.
    You did WHAT???!!!??? Well, that makes you a Moron.
    We at %&^* Healthcare consider that a pre-existing condition.

  8. #8
    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.

  9. #9
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    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.

  10. #10
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    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

  11. #11
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    Some vfd's are full rated output on single phase input. others are derated to 75%. Even with true three phase a VFD is a good thing on drill presses etc. where variable speed is nice to have.
    Bill D

  12. Working on restoring a covel surface grinder. I am using a Teco Drive like these http://www.factorymation.com/acdrives

  13. #13
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    Before getting into converters contact your utility and see about availability of 3 phase. You might find though that under no circumstances will they provide it to a residence. I went the rotary route and installed a 3 phase panel fed by the converter. I have a Kay and have had no problems in 12 years of commercial use.
    Steve Jenkins, McKinney, TX. 469 742-9694
    Always use the word "impossible" with extreme caution

  14. #14
    Quote Originally Posted by Alan Lightstone View Post
    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?
    vFD's were generally develop for three phase power and only in recent years have they been used for single phase conversion. They initially were never designed for that it just so happen they can do that . About eight years ago single phase input drives appeared on the market to accommodate single phase strictly . The first ones were both single and three phase input . Generally these went to three horse power and not much larger .

    A few years ago I worked in conjunction with a large manufacture and I'm having single phase input VFD's custom made for woodworking machinery and specifically for single phase input . This means that the parameters for the drive are for single phase purposes and outputs are proper for the drive size . My drives are not the derated.
    I supply drives up to 15 hp single phase input . Our single phase 5 Horse Drive is $275 plus shipping . And that includes walking you through step-by-step on getting it set up in your machine running . These are state of the art drives . If you go to "Jack English machines " on you tube there's a playlist and contact information if you're interested. You can generally run approximately 50 horse power off a residential service .
    Last edited by jack forsberg; 09-22-2017 at 10:09 AM.
    jack
    English machines

  15. #15
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    What Dave said.

    Also, economic savings by planning to move a single VFD from machine to machine would be challenging and not especially extensible though certainly it has been done. The key benefit would be cheaper wiring, either a high(er) amperage single-phase 220v or extension cord. Programming would need to be consistent which might be more challenging. You would need to program your VFD to allow storing different sets of criteria ... ramp up, slow down, jog ... for each machine. Or use criteria applicable to all the machines.

    Also, VFD typically come in an IP20 or possibly NEMA 1 enclosure. If you feel your environment requires greater protection than that (likely) you'll need to plan accordingly and that can get expensive. So for instance, the popular Teco FM50 comes available in IP20 as a 3hp unit (the FM50-203C) for about $200 or as a NEMA4 (FM50-203-N4FS) for $500. The recommended volume for a VFD in a NEMA 3 puts buying that separately as a not inconsequential cost. All that starts to make the RPC more attractive.
    "the mechanic that would perfect his work must first sharpen his tools. Confucius

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