Looking for a motor..

Discussion in 'Research and Development' started by GregMcFadden, Jun 11, 2015.

  1. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    I have a little subsecret R&D going on and i realized that I need to find a suitable motor with the following target specs:

    operating voltage: any, can go as high as ~60-100V with modern ESC's.... but I would prefer to keep it below 30V if possible.

    Speed under load: 9500RPM
    Power under load (electrical input) 1000W-1300W

    any ideas on available hobby motors people?
     
  2. thegeek

    thegeek Well-Known Member

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    National Electric Code used to limit you to 48 VDC. But even at that you feel it at anything above 40 VDC. Why so high a target?
    Most Red Chinese ESC's from Hobbyking can't go more than about 7 cells of LiPo (about 24 VDC), and they can in general be good for our use/abuse.
     
  3. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    no real reason other than current consumption... my real needs are power and RPM... voltage is a variable but keeping it within the abilities of cheap chinese ESC's is good. I do want to avoid something like 6V at 216A... 24V at 54A is much more reasonable
     
  4. SteveT44

    SteveT44 Well-Known Member

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    Brushed or brushless?
     
  5. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    I would preferr brushless as it may be fully submerged/contained due to structural needs
     
  6. SteveT44

    SteveT44 Well-Known Member

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    Not certain an the wattage of these but they certainly look intriguing. I bet Carl buys some to play with.

    3-PHASE BRUSHLESS DC MOTOR | All Electronics Corp.
     
  7. thegeek

    thegeek Well-Known Member

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  8. jch72

    jch72 Active Member

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    Look at hobbyking. Turnigy 500 and 600 outrunners fit the bill. The red anodized ones with chromed cans. Some are even as high as 2.5 kilowatt peak power.
     
  9. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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  10. irnuke

    irnuke -->> C T D <<--

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    Ah, c'mon.... run it at 6V and use 22-gauge wire.
     
  11. jch72

    jch72 Active Member

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    absolutek likes this.
  12. buttsakauf

    buttsakauf Well-Known Member

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  13. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    Well, since I finished enough preliminary work to decide that I would not be taking the project any further, the motor was for a pump. A rediculously absurd pump that was a not so simple thought exercise on whether one could simply throw money at a pump and get a significant performance increase. The answer was yes. generally speaking it is a 3.3" diameter pump impeller translating into a ~4.5" diameter pump housing running at 8-12k rpm producing ~125psi total pressure rise at ~4 gallons per minute. It probably would have had a 1-2 season life due to blade erosion particularly with plastics, but that would get you ~4gpm out of a 1/8" orifice (maybe a bit more). power consumption looked to be a relatively miserly 800-1300W.... Batteries for ~1hr of operation would run about 500-1000$... use a similar design for a ~2gpm half unit pump
     
  14. thegeek

    thegeek Well-Known Member

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    so outside of a Yamato what boat would this be installed in?
     
  15. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    Realistically with any modern set of batteries it could have fit in most of the larger battleships.... sizing it out slightly smaller for the 1/2 unit orifice I think I could shoehorn it into a provence but it would again be a huge expendature of money to keep all the rest ofthe parts in the ship light enough to accomadate it... it was mostly a thought/numerical experiment to see what could be done if I followed the pump design laws coupled with some info I learned recently about low Ns pumps.... it will never be built for several reasons beyond cost... besides, I am more interested right now in an interrupterless, easy to build by hand cannon that works off my air compressor but needs further testing...
     
    Last edited: Jun 15, 2015
  16. thegeek

    thegeek Well-Known Member

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    So you didn't really build it? Just math? I find that real would testing is the only way, math is just math not water.
     
  17. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    well that and the utilization of some weekend training on some software packages that are intended for the purpose. I don't have a spare grand laying around to build and test something that I would never release.
     
    KeriMorgret likes this.
  18. NickMyers

    NickMyers Admin RCWC Staff

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    I've seen enough of Greg's work to know that if he says the math works and the model in sim works then the real thing would work.
    Unfortunately this isnt something you can knock together on your workbench or run off on ye old FDM printer.
     
  19. thegeek

    thegeek Well-Known Member

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    Nah, yes you can build a prototype and yes math helps but it does not equal a real test. I think I know how to build a pump.
     
  20. KeriMorgret

    KeriMorgret Facilitator RCWC Staff Vendor

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    The P.E. in Greg's email signature is enough to convince me.