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

How to convert 5 volts to 12 volts for a USB Motor

  1. Aug 22, 2008 #1
    Hi everyone,
    What I am wondering is if there is a way to convert 5 volts to 12 volts. The application I will be using this for is a USB driven motor. The USB cable can only handle 5 volts and the motor is 12 volts. So I am wondering if there is a device or something simple to build that can bridge the gap between the voltages. Thank you for your advice!
    Sincerely
    Chris
     
  2. jcsd
  3. Aug 22, 2008 #2

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Look up dc-dc converter (or boost converter)
    But remember that USB can only supply 500mA and the converter will waste some power
     
  4. Aug 23, 2008 #3

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Summit, your USB cable isn't limited by voltage, but by current.
     
  5. Aug 23, 2008 #4

    russ_watters

    User Avatar

    Staff: Mentor

    ...and therefore it is probably better to find a suitable 5V motor.
     
  6. Aug 24, 2008 #5
    Thank you for the advice, much appreciated. Would the same apply if I replaced the USB cable with a Parallel port cable?
     
  7. Aug 24, 2008 #6

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Yes the same would apply. The problem is nothing to do with the cable, but your understanding of electrics.

    Depending on what you're trying to do (let us know!), I'd go forward with your USB idea with a suitable 5V motor, making sure that you're not going to exceed the relevant current limits.
     
  8. Aug 25, 2008 #7

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    Unlike USB, which has a designated power connection, Parallel Ports are not designed to provide any power.
    Parallel Ports have only signal level outputs.
     
  9. Aug 25, 2008 #8
    More information is required regarding the motor you are trying to drive. Simply describing it as a 12 volt motor is not sufficient. The kw rating, or horsepower rating, full load current rating is required to determine the power needed to run the motor. Can you describe the motor with more specificity?

    I am thinking you may need a separate 12 volt power supply that allows for voltage driven input control.
     
  10. Aug 25, 2008 #9
    Thank you again for the advice here are the technical specs of the motor.
    HP: 1/10
    RPM: 2300
    Rotation: Reversible
    Torque (oz-in): 40
    Field Volts: 12
    Diameter: 3in
    Shaft Dimension (inches): 5/16 x 2
     
  11. Aug 25, 2008 #10

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    1/10 of a horsepower is 75W
    At 12V that is 6.5A, USB can supply 5v at 500ma = 2.5W = 1/300 HP
    I think you are slightly out of luck!

    You could use a car battery to power the motor and a USB device to control a relay to turn it on/off.
     
  12. Aug 25, 2008 #11
    I was crunching the numbers as well and came to that same conclusion. Back to the drawing board it seems...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: How to convert 5 volts to 12 volts for a USB Motor
  1. How to get to 12 volts? (Replies: 14)

Loading...