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

  1. #61
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    I'm waiting to hear back from the electric company down here as to whether it is possible to get 3-phase power from the utility to the workshop. I should hear back in a few days. If not, it will be either a Phase Perfect, or multiple VFDs, or perhaps just wait until Felder can get me 230V 1phase motors in the needed sizes.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  2. #62
    Quote Originally Posted by Alan Lightstone View Post
    Now having to carry 100 amps for a 115 V circuit would be crazy big and expensive. What is that, 2ga or 3ga wire??? The route I won't take.
    Isn't amperage, amperage? The wire doesn't care about the voltage? Or am I way off base here?

  3. #63
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    Halving the voltage doubles the amperage to get the same power.

    P=IxV
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  4. #64
    Quote Originally Posted by Alan Lightstone View Post
    Halving the voltage doubles the amperage to get the same power.

    P=IxV
    I get that. But isn't the amperage capacity of a given piece of wire the same regardless of voltage? You get more power with 10 amps on 480v than 110, but it's still 10amps?

  5. #65
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    Quote Originally Posted by Martin Wasner View Post
    I get that. But isn't the amperage capacity of a given piece of wire the same regardless of voltage? You get more power with 10 amps on 480v than 110, but it's still 10amps?
    True, but ordering a 115V 1 phase motor with equivalent HP to the 230V 3-phase requires more current, which then requires larger diameter wire to carry it. I was comparing apples to oranges (115V 1 phase to 230V 3-phase). Not a fair comparison, but it's astounding how much current a 115V 7.5HP motor requires. I really was pointing out the absurdity of that option.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  6. #66
    Quote Originally Posted by Bruce Wrenn View Post
    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

  7. #67
    Quote Originally Posted by Alan Lightstone View Post
    True, but ordering a 115V 1 phase motor with equivalent HP to the 230V 3-phase requires more current, which then requires larger diameter wire to carry it. I was comparing apples to oranges (115V 1 phase to 230V 3-phase). Not a fair comparison, but it's astounding how much current a 115V 7.5HP motor requires. I really was pointing out the absurdity of that option.
    I understand that you're just going under theory but the fact of the matter is a motor in that configured of winding would never exist . Mostly because of the winding wire size would not fit into the stator core . So generally you'll only find single phase dual voltage Motors up ton3 hp 120/240 i'm not sure what the upper limit is on dual voltage three phase but that's a different type of winding and Motor configuration . 230/460 here in Canada we also have 600 V these are never dual voltage windings . But I have run across six wire star Delta wound 600 volt Motors that were prepared in England for shipment to Canada . Generally European motors arevnot wound the same as the nine lead American style .
    jack
    English machines

  8. #68
    Quote Originally Posted by jack forsberg View Post
    Generally European motors are not wound the same as the nine lead American style .
    And I have yet to see a euro motor with a diagram under the doghouse cover explaining what taps to use to switch voltages. It's infuriating. Blowing stuff up is only fun when intentional.

  9. #69
    Quote Originally Posted by Martin Wasner View Post
    And I have yet to see a euro motor with a diagram under the doghouse cover explaining what taps to use to switch voltages. It's infuriating. Blowing stuff up is only fun when intentional.
    The German stuff usually does, the Italian stuff sucks about that.

  10. #70
    Quote Originally Posted by Martin Wasner View Post
    Isn't amperage, amperage? The wire doesn't care about the voltage? Or am I way off base here?
    Amperage and voltage are inversely proportional. And wire has to have insulation rated for the voltage it carries.

  11. #71
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    So the quote came in from Felder, with a disclaimer that the rep gave the wrong information initially, and only the A941 jointer can come with a 1 phase motor. So, I really do need 3-phase power for these beasts. Either directly from the utility, or via phase conversion of one type or another.

    So many useful bits of information from everyone. Awesome responses, guys. Please keep them coming.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  12. #72
    Quote Originally Posted by Chris Hachet View Post
    Amperage and voltage are inversely proportional. And wire has to have insulation rated for the voltage it carries.
    ^+1 Or, same idea with slight twist: The conductor size determines the maximum amperage a wire can safely carry; the insulation (thickness & material) determines the maximum voltage a wire can safely carry.

    And of course there are eleventy-seven other factors (conduit, wireway, # of conductors, etc.) that are used to adjust the above max value. ....gotta love those codes!

  13. #73
    Quote Originally Posted by jack forsberg View Post
    I understand that you're just going under theory but the fact of the matter is a motor in that configured of winding would never exist . Mostly because of the winding wire size would not fit into the stator core . So generally you'll only find single phase dual voltage Motors up ton3 hp 120/240 i'm not sure what the upper limit is on dual voltage three phase but that's a different type of winding and Motor configuration . 230/460 here in Canada we also have 600 V these are never dual voltage windings . But I have run across six wire star Delta wound 600 volt Motors that were prepared in England for shipment to Canada . Generally European motors arevnot wound the same as the nine lead American style .
    Not to belabor the point, but Baldor does list a 15hp/230V/1ph motor in their online catalog. No idea if they have ever actually built one.

  14. #74
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    Jul 2014
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    Quote Originally Posted by Alan Lightstone View Post
    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.

  15. #75
    Quote Originally Posted by Alan Lightstone View Post
    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.
    Last edited by Malcolm McLeod; 09-27-2017 at 8:48 PM. Reason: disclaimer

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