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Thread: Let’s talk three phase...?

  1. #1

    Let’s talk three phase...?

    Let’s talk three phase.?


    As a residential consumer there is absolutely no reason to buy brand new three phase equipment in my opinion.

    Looking through auctions and buying three phase equipment has its pluses....

    You’re buying this from industry which consider these machines almost garbage.

    Some of these machines are 230 V three-phase, 460 V three-phase, 550 V three phase, 600 V three-phase.

    If you’re in residential and you only have 240 V single phase, don’t look at this gifted horse in the mouth!

    Many machines can be converted using VFD’s, RPCs, PP’s(Phase Perfect) and static phase converter‘s .

    Each conversion method has its pros and cons....

    But, if you’re buying A surface grinder for $50 like I just did that is 550 V., that has three motors… What do you do?

  2. #2
    you simply cant compare the quality of single phase machines to so many great three phase machines older and even newer that are available. Whats the HP of the motors, old guy I bought machines from ran a stroke sander and combination machine off a simple roto for likely 30 years. 3 HP Roto 3 HP motors in the combo machine.
    Last edited by Warren Lake; 06-19-2018 at 2:03 AM.

  3. #3
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    "As a residential consumer there is absolutely no reason to buy brand new three phase equipment in my opinion"

    I respectfully disagree. I am a "residential consumer" and both my bowl lathe and my drill press are relatively new machines and both are 220 3-phase with single phase 220 to three phase 220 VFD's on them. The infinitely variable speed is much better than I was able to achieve in any other way and there were no wiring issues, since I had already wired 220 into my basement shop to handle my table saw, dust collector and jointer.
    Grant
    Ottawa ON

  4. #4
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    [QUOTE=Matt Mattingley;2823307]Let’s talk three phase.?


    As a residential consumer there is absolutely no reason to buy brand new three phase equipment in my opinion.

    QUOTE]

    I disagree Matt, I know people who have bought new 3 phase equipment for their home shop. A lot of new wood working machinery isn't available in single phase..........Rod.

  5. #5
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    Jeff, Yes, 3 phase motor currents are lower than a single phase motor however their power consumption is approximately the same.

    I have single phase high power factor, high efficiency motors that are more efficient than older 3 phase motors.

    The single phase motor torque characteristics have nothing to do with how many "hot" leads there are, as most machine motors are 240 volts with 2 hot leads.

    As to reversibility, single phase motors can be reversed by reversing 2 leads, either the start or run windings.

    Regards, Rod.
    Last edited by Rod Sheridan; 06-19-2018 at 9:56 AM.

  6. #6
    Quote Originally Posted by Jeff Heath View Post
    You know what, Rod......maybe I didn't type it well enough to explain it well enough to a guy like you, but my education is as an electrical engineer, and I understand how power systems work....quite well.
    Jeff, your post seems to be missing.
    Last edited by Lee Schierer; 06-19-2018 at 4:09 PM.

  7. #7
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    Yep.....so am I. So long....
    Jeff

  8. #8
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    My take is that the word " absolutely " is too strong but the idea is valid. The economics of high end used equipment vs similarly priced new is pretty compelling. I'm not a bottom feeder and can afford any new machines I would want but I'd rather spend for other dumb stuff. A new three phase industrial sliding table saw is in the 15-20K range minimum. A used industrial machine is 5-8K and less if you shop well. My SAC 530 planer was 4K and like new. My T130 sliding shaper was 3750 and never used. etc, etc. I had to learn basics about electricity, bearings, and develop a relationship with a machinist but that is part of the fun for me. Edge and Disk sanders are way better and way cheaper used, but there are some new machines that have some benefits that make their higher price and lesser build appropriate.

    Beyond that, three phase is now available to anyone for less than the cost savings available if you are willing to learn the used market. I have VFDs, RPCs, and several Phase Perfects. All have their place and none are deal breakers from a cost standpoint. I also have transformers for 275v, 480, and 600v. None are that complicated to figure out if it turns out the motors can't be rewound. Even factoring in the cost of the electricity conversion, used equipment comes in much cheaper than new. For a hobby guy, new high end three phase equipment is a choice similar to buying a new Mercedes S550 instead of a two year old one with 1500 miles at a 40K discount. ( It still depreciates really fast ). Dave

  9. #9
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    Jeff, since I'm not allowed to see the post, I don't know the circumstances but don't leave. Diversity of opinion is good and people who know both woodworking methods and understand the machines that accomplish the task are rare. Dave

  10. #10
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    Jeff, there are some very sensitive people on this forum, too sensitive in my opinion. But I don’t make the rules so I have to abide by them just like you do.

    Taking your ball am leaving seems a bit immature, no offense intended. Please stick around and continue to contribute to our discussions.

  11. #11
    Jeff Rod is one of he nicest people on the planet. There are 2000 plus people in my phone book im a fairly good judge from knowing so many. Ive been very lucky. Rods been here before the only thing I dont like about him is he is so smart. Im joking as I do like that, its just that im not and have a different brain, he also doesnt present himself that way which is nice.

    Those were just the words he used, hes the last guy meaning to offend someone. Now me Im good at it, id claim I learned it from Martin but people would know its already been there. (you can call my sister she will verify)

    Anyway Rod meant no offense. The bit I know him its instant where his heart is. When you ask someone to help you and you ask what they want to do that and they say a tea you clearly realize you are talking to a certain type of person.

  12. #12
    Quote Originally Posted by Matt Mattingley View Post
    Let’s talk three phase.?


    As a residential consumer there is absolutely no reason to buy brand new three phase equipment in my opinion.
    I am a residential consumer and buy three-phase equipment whenever I can. My house, as well as most houses in Germany, are wired with 230/400 three-phase service.

  13. #13
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    [QUOTE=Mike Kreinhop;2823519]I am a residential consumer and buy three-phase equipment whenever I can. My house, as well as most houses in Germany, are wired with 230/400 three-phase service.

    You are Lucky; If you had 600 volts as well I would move to Germany.

  14. #14
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    I really hope zero people around me disagree with Matt.

    If you bought higher voltage equip and three phase, you will need a transformer and rpc.

  15. #15
    I agree that often as not - "normal" residential electricians never see a need to install 3 phase power into dwellings.... 99% of people would never use it for anything....

    Often as not - you can get 3 phase 208 in many residential and light commercial areas. That's simply 3 phase where each leg is regular 120v... 220 is similar - except that it is 2 phase with 120 on each leg....

    if you can get 208 3 phase easily enough - all you need is an appropriate step up transformer and off you go... These can be bought used cheap...

    I personally would not buy equipment that requires anything higher than 480 3 phase... Above that - you start pushing up into "Medium voltage" stuff and electricity behaves differently. You have to be VERY careful about wire terminations as well as keeping breakers properly maintained. This is the realm of paying electricians - not doing it yourself.. You can kill yourself in a hurry...

    Even then - you will likely have to find an electician who has the correct credentials/qualifications/training and equipment to work on a system above 480v... Most simply do not.....
    Last edited by John C Cox; 06-19-2018 at 5:05 PM.

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