Convert DC motor to AC?

Discussion in 'General Electronics Chat' started by C44play, Oct 8, 2013.

  1. C44play

    Thread Starter New Member

    Oct 8, 2013
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    I have the following motor:
    DC
    130v
    250 rpm
    Cont
    21 lb-in

    I would like to be able to plug it in to an AC outlet. How do I go about doing this? I have very little electronics experience but can follow basic directions. Thanks for all the help in advance!:confused:
     
  2. shteii01

    AAC Fanatic!

    Feb 19, 2010
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    Last edited: Oct 8, 2013
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Look on ebay for KB or Baldor (relabeled) KBIC-120 etc DC SCR drives.
    Operates off of AC, no DC Power supply required.
    Will also give variable speed.
    As long as it is Brushed DC and not BLDC?
    That must have a G.B. attached for that low a rpm?
    Max.
     
  4. C44play

    Thread Starter New Member

    Oct 8, 2013
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    Thank you. I'm trying to figure our a way to post a pic of the motor here but can't figure it out.
     
  5. C44play

    Thread Starter New Member

    Oct 8, 2013
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  6. MaxHeadRoom

    Expert

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    Yes it has a 10:1 G.B. attached so the max rpm of the motor is 2500.
    If you just want to run full rpm then a bridge rectifier off of the 120v is all you need, and an on/off switch, of course.
    Max.
     
  7. C44play

    Thread Starter New Member

    Oct 8, 2013
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    So I just wire from the AC to the bridge rectifier and from the bridge rectifier to the on/off switch? Then from the on/off switch to the motor?
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Or probably best to put the switch on the AC side of the bridge.
    Max.
     
  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Max, is that really a good idea? 120VAC to DC is around 170VDC when rectified, isn't it? Plus it it violates AAC TOS policy. A 120V to ~85V transformer should be in the mix somewhere, shouldn't it?

    Plus if I remember correctly, those Bodine motors are wound field motors, not permanent magnet motors.
     
  10. MaxHeadRoom

    Expert

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    The ones I have used have all been P.M.
    It is only ~170vdc if smoothed, which is not needed in this app, if the OP want to play it safe he could fit a 120/120v transformer.
    But the KB SCR drives I use for these motors will operate directly off the 120v AC supply. (SCR bridge).
    The down side to using a bridge direct is the high inrush current at switch on which requires an adequate bridge rating.
    Max.
     
  11. C44play

    Thread Starter New Member

    Oct 8, 2013
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    I'm reading what you gentleman are writing but I'm not understanding. Can you break it down "big bird style" for me please and let me know what I need to do to get it running? Or is there something out there that I can buy that is already built that I can just wire up?
     
  12. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The content of post #7 & #8 pretty much answer the very simplest answer, otherwise get a KBIC-120 or equiv controller off ebay for $30.00, four connections and you are running.
    Max.
     
  13. C44play

    Thread Starter New Member

    Oct 8, 2013
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    Do I need to wire in a capacitor?
     
  14. MaxHeadRoom

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    No, should not be needed.
    Max.
     
  15. C44play

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    Oct 8, 2013
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  16. MaxHeadRoom

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    Are you sure you have the bridge hooked up OK,
    What is the nature of that controller you have between the bridge and power?
    Try the motor on an automotive battery first to test it.
    Max.
     
  17. ian field

    Distinguished Member

    Oct 27, 2012
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    If the motor has a field winding; it may already be compatible with AC supply, if its a permanent magnet DC motor; the least you will need is a rectifier.
     
  18. C44play

    Thread Starter New Member

    Oct 8, 2013
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    So it would be okay to hook it up to a 12v car battery even though it is a 120DCV?
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Yes, it will, or should run at a rpm at the ratio of the voltage, ~250rpm.
    If it only had two wires it is P.M. field and Bodine motors such as those generally are.
    Max.
     
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