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Did I spend too much on this motor? (3 Ph Discussion and Shenanigans)

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Don Nguyen, Mar 21, 2012.

  1. Don Nguyen

    Don Nguyen

    Oct 4, 2011
    New Questions (3/22/2012)

    Ok, just in this single purchase of the motor, I have learned more in one day than I did in one year.

    That brings me to some new questions:

    -If I want to run a Single Phase AC motor, I don't need anything more to run it, right? Just plug it in a go (assuming "normal" conditions).
    -If I want to run a Three Phase AC motor, I need three phase power, either by a converter or VFD.
    -If I want to run a Permanent Magnet DC motor, then I need DC power, either by a DC controller or voltage converter, right?

    -----

    Original Post


    [​IMG]
    [​IMG]

    $100

    I mean, I probably can't just plug it in my garage and start using it, can I?

    It's kind of big and heavy.
     
    Last edited: Mar 22, 2012
  2. knife to a gunfight

    knife to a gunfight KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 17, 2007
    You know it is a 3 phase right?
     
  3. thegeek574

    thegeek574

    Sep 3, 2010
    7.5 horsepower? that is a really powerful motor. I would hold onto it until you can get a VFD, and then use it. that won't bog for anything.
     
  4. jawilder

    jawilder

    Jun 27, 2006
    You would need more than a VFD. You would also need a phase converter and more than 110v in your shop. It would be good on a press but way overkill on a grinder.
    Jason
     
  5. Remyrw

    Remyrw

    Jun 17, 2010
    holy hell, that's a monster for knife making.
     
  6. Big Chris

    Big Chris SAHD/Knifemaker Knifemaker / Craftsman / Service Provider

    Apr 1, 2010
    That is a good deal for a three phase motor that size. You will need a phase converter to run in your shop. You could build a very good hydraulic press with it.
     
  7. A C Richards

    A C Richards KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Apr 14, 2006
    Too big for a belt but perfect for a press. You paid way to much though, I'll take it off your hands for $150 :D
     
  8. butcher_block

    butcher_block KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 6, 2004
    that woudl power a 36" wheel grinder nicly tho
     
  9. A C Richards

    A C Richards KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Apr 14, 2006
    Don't tell Sam :D
     
  10. Sam Salvati

    Sam Salvati

    Aug 6, 2007
    I'd run a 2x72 on that motor! Why not? Would be awesome on a pwoerhammer too. I would use that specific motor FOR a phas converter, then score another 3 phase in the 3 horsepower range.
     
  11. Don Nguyen

    Don Nguyen

    Oct 4, 2011
    The guy was selling two other 3ph 5hp motors for about the same price. Maybe I should get back to him?!

    I dunno, I was thinking maybe I could sell this for a bit more than I bought it and use the money to contribute to my upcoming grinder.

    EDIT: As much as the money is tempting me, I think I will keep it for future use, or if I can find another really cheap 3ph motor I will use this 7.5hp as a converter (as Sam recommended).
     
    Last edited: Mar 22, 2012
  12. A C Richards

    A C Richards KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Apr 14, 2006
    Sam, I was reminded of your 36" grinder attempt. :eek:
     
  13. Brian Ayres

    Brian Ayres

    Feb 4, 2011
    Like this? Hmmmm... http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

    And come on Sam, not going to bite on the 36" wheel idea! Lol
     
  14. tryppyr

    tryppyr KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 5, 2010
    I noticed it's not a TEFC, so not really suitable for a grinder. It says OFGB if I read it correctly.
     
  15. Don Hanson III

    Don Hanson III KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 3, 2002
    If a VFD could be had reasonably, I'd be hookin it up to one of my grinders. :D
     
  16. A C Richards

    A C Richards KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Apr 14, 2006
    Yup not a fan cooled motor. Need to watch the op time. You can get a good 10hp phase converter for $735 delivered. I have one and since it comes with the cap starter pack well worth the investment. Mine easily runs all my motors. They suggest you run 1/2 the hp of the converter. However if it is a no load start a 7.5 would run just fine. The company is great also, they have a killer warranty and stand by their product. If I had to do it over again I would have purchased this unit many years earlier. If anyone would like the info please PM or email me and I will send the co information. I have no affiliation with this co, just a very satisfied customer.
     
  17. woodwrkr221

    woodwrkr221

    391
    Jan 28, 2011
    You could power five KMG's running simultaneously off of a common line-shaft powered by that motor! Just think how convenient that would be!
     
  18. watercrawl

    watercrawl

    422
    Jun 2, 2006
    Pardon my stupidity, but why would one need a phase converter and a VFD for this motor?
     
  19. Don Nguyen

    Don Nguyen

    Oct 4, 2011
    It is a 3 phase motor, which requires 3 phase power, and isn't available at homes and whatnot. So one option would be to get a phase converter that provides 3 phase power from single phase. I'm not sure about the VFD, looking forward to answers on that.



    I don't think I'll be using it any time soon. I'll probably keep it for later use as a converter, or maybe hook it up (via belt) to a grinder from an enclosed area :)
     
  20. watercrawl

    watercrawl

    422
    Jun 2, 2006
    But a VFD works as both a phase converter and a speed control for 3 phase motors....hence my question.

    Due to the size of the motor?
     

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