What power supply is suitable to run the pictured 12v DC motor?

Discussion in 'The Projects Forum' started by sky-high-11, Apr 21, 2015.

  1. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    I have tried to power this motor using a computer power supply by tying all the grounds together and tying all the 12v leads together. The power supply trips when the PWM direction switch is thrown requiring turning the supply off and on again. I don't know how many Amps this power supply puts out.
    My PWM is rated at 10a and the motor markings is just 12volt.

    1) What Power Supply would be best for this motor?

    2) Would higher voltage increase speed or torque?

    3) Additional thoughts appreciated.

    Thanks, Rick
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    why dont you try it on a car battery and measure the current.
     
  3. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    I will check utube on how to do that.
    My knowledge of electricity was learned as a kid when I stuck my finger into a live bulb socket and it hasn't improved much.

    thanks Rick
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    get an ammeter or dmm and connect it in series with the motor and battery.
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    When using a car battery, Start with the ammeter on the 20A ( or 10A) scale.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Of course you are going to trip a PC P.S. with that motor, particularly if starting from a non-zero state, you need a linear supply for that motor.
    A simple AC supply with a bridge rectifier will run it if the PWM unit has built in Capacitors.
    BTW with a PWM control you are not tied to the plate voltage of the motor, it can be at least 10% above the motor rating.
    Max..
     
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  7. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    Is a linear ps the same as a switching ps?
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    No a different construction.
    The linear is much simpler from a technical PoV.
    SMPS is not needed for motor control.
    Max.
     
  9. ronv

    AAC Fanatic!

    Nov 12, 2008
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    When a motor is reversed it acts as a generator until the direction changes. This voltage is added to the power supply voltage. This probably makes an over voltage circuit trip in the supply. Let it stop before the reversal.
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This would only occur if the motor were to increase rpm after the power was removed.
    At the point of power removal it is almost equal or less, depending on load.
    Max.
     
  11. Papabravo

    Expert

    Feb 24, 2006
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    The transient response to a step change in load of a SMPS is generally very poor. They can be designed to be 'stiffer', but this is not usually the case.
     
  12. ronv

    AAC Fanatic!

    Nov 12, 2008
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    No, it happens on any reversal where the motor is still spinning in one direction and is driven in the other direction. It's not a problem with batteries because it just charges them and the voltage doesn't rise much. This has gotten me twice. Easy to view the power supply as a battery.
     
  13. Reloadron

    Active Member

    Jan 15, 2015
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    Maradyne Corporation is located here in Cleveland, Ohio so depending on your location you have nothing to lose by giving them a call at (216) 362-0755 and describing your motor. They may be able to send you a data sheet on that motor. Nothing to lose. The motor looks to be a small gear head motor and looking at the wires hard to tell but does not look to be a high current motor. My guess is the sudden reversal may be an issue. Will the motor start and run in forward or reverse from the start? When you reverse is it just a sudden change or is the motor allowed to halt and then reverse? I tend to agree with ronv as to the sudden reversal being the problem.

    Again, while the Maradyne website does not show your motor I would give them a call as they may be able to fix you up with a data sheet or at least some specifications. Those motors were likely sold exclusively to the auto manufacturing industry locally here in Cleveland.

    Ron
     
  14. tcmtech

    Well-Known Member

    Nov 4, 2013
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    A cheap automotive battery charger with a few large capacitors added to its output make as for a pretty good and highly forgiving low voltage DC motor driver power supply. That's what I would be looking to use.
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Clarify: I may have misunderstood your comment, but the motor will generate the same polarity as the driven direction, if the power is reversed before a stop, then the current is extremely high, as the applied power is opposite polarity to the generated and will oppose each other.
    Max.
     
  16. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    I will attach the motor to a 12v battery this weekend and check the amps so I can choose the right PS.
    If I attached a 12v 10a PS and the motor was rated 12v 5a, what would happen? I was told long ago that it would use only the amps needed while in a similar situation the speakers went up in smoke.
    Incidentally ya'll talk in a foreign language but I follow most tips and appreciate the huge response.

    Thank, Rick
     
  17. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    Thanks for the heads-up, Will follow-up, Rick
     
  18. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    Will try that this weekend. I do have a 3 position switch installed.
    Rick
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This is correct, the current demand is high initially if you were to power with 12v directly, if you are using PWM then you can control the speed from 0 to 12v.
    It is wise to power up when the control is zero and to make sure the motor is stopped before reversing.
    Max.
     
  20. sky-high-11

    Thread Starter New Member

    Apr 16, 2015
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    Is this a possible PS for my motor?
    http://www.ebay.com/itm/12-VOLT-10-...R-120W-WITH-METAL-CASE-NEW-TYPE-/121309015731
     
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