Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need Recommendations For An Electric Motor

  1. Apr 28, 2007 #1
    I need to select an electric motor. There is little to no torque involved so that's not really a factor, but it has to be able to run off of standard house-hold power and as a main parameter have as wide of a range as possible of flexibility in variable speed control, preferably from 0 rpm to as high as possible. Does anyone have any suggestions?
     
    Last edited: Apr 28, 2007
  2. jcsd
  3. Apr 28, 2007 #2
    Is the motor DC or AC?
     
  4. Apr 28, 2007 #3

    turbo

    User Avatar
    Gold Member

    The upper rpm range may not be as fast as you want, but a ceiling-fan motor with an 120V AC rheostat can go pretty slow and you can ramp up the speed pretty smoothly. Of course many of those motors are bulky, but you might be able to pick one up for free if your local landfill/transfer/recycling station sets "interesting" stuff aside for the patrons to look over. The town saves on landfill costs, and the tinkerers get free stuff.
     
    Last edited: Apr 28, 2007
  5. Apr 28, 2007 #4
    Waht, the motor will be run on standard AC residential household power.

    Thanks for the feedback.
     
  6. Apr 28, 2007 #5

    turbo

    User Avatar
    Gold Member

    Sorry, I dropped a 0. I meant 120V AC - just the standard vanilla ceiling fan. I edited that.
     
  7. Apr 28, 2007 #6

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

    Why not use a DC motor and speed controller powered by an AC to DC adapter? There are many hobby motors for model airplanes and cars.
     
  8. Apr 28, 2007 #7

    Danger

    User Avatar
    Gold Member

    I agree with Digoff on this. You can get DC motors for free just by scavenging scrapped VCR's, electric toothbrushes, etc.. Just match a power supply and you're set.
     
  9. Apr 29, 2007 #8

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    If accurately controlled zero or near zero rpm is a requirement then you may need to use a stepper motor.

    Alternatively a switching power controller, such as found in variable speed drills (120 AC or DC portable variants), will provide much more consistent operation at low rpm.

    Edit: Something like a Dremel tool will go from near 0 to > 10k rpm.
     
    Last edited: Apr 29, 2007
  10. Apr 30, 2007 #9

    dlgoff

    User Avatar
    Science Advisor
    Gold Member

  11. Apr 30, 2007 #10
    hi,
    what do you want to know about AC or DC motor ?
    BR,
     
  12. May 19, 2007 #11
    Hi Everyone,
    I apologize for not getting back sooner, corporate life has a habit of getting in the way sometimes. Thank you very much for all of the feedback; I really appreciate the ideas you've given me as I hadn't thought down some of those lines before. To answer a couple of the questions, I'm needing an electric motor that can run on standard household AC power (110V-115V) as I have a mechanical hand-dial type inline reostat that plugs into an outlet and the motor would plug into that. The reostat is capable of adjustments in 3%+/- increments from no power up to full power. At least that was the way it was explained to me. My primary purpose behind my OP is to find the right kind of AC motor to handle that kind of manual power fluctuation and not burn out too soon. I'm guesstimating that a small motor around the size of 1/4 hp would be big enough, though I can certainly go larger if recommended by people who know better than me. I probably also should have asked about the versatility of Single-phase vs. 3-phase as well.

    At any rate, I really like the idea of using a ceiling fan motor, but what concerns me there is that I need to mount the motor horizontally and for some reason I've always thought they were made to only be operated vertically. Can anyone verify / clear this up for me? Once again, thank you all very much for your help.
     
  13. May 19, 2007 #12

    Q_Goest

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

  14. May 19, 2007 #13

    Danger

    User Avatar
    Gold Member

    Ceiling fan motors can operate at any angle. With the fan attached, you'd pound the hell out of the bearings if it isn't vertical. Since you said that this is a low-torque situation, that shouldn't be an issue.
    I don't know about where you are, but here 3-phase power is a special installation and you pay through the nose for it.
    And NoTime, most Dremels top out at 30,000 rpm, not 10,000. Even my cordless one does more than 25.
     
  15. May 20, 2007 #14

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    There is that > :wink: :smile:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Need Recommendations For An Electric Motor
  1. Electric Motors (Replies: 3)

  2. Electric Motor (Replies: 12)

Loading...