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How to get high voltage but NO amps

  1. Aug 28, 2009 #1


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    hi everyone im new here and no nothing about physics. with that being said, what would you do in order to run over 96V but get no amps or get very little amps...
  2. jcsd
  3. Aug 28, 2009 #2


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    Gold Member

    Well, you'll get no amps as long as the circuit isn't complete but you can still have high potential (voltage).
  4. Aug 28, 2009 #3
    A 96 voltage battery or alteranator will do that....If you can do with120 volts then most outlets in the US will also.

    If you are thinking about a complete circuit,an arbitrarily high resistance will limit current to an arbitrarily low value.
  5. Aug 28, 2009 #4


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    Science Advisor

    What is the purpose of this?
  6. Aug 29, 2009 #5
    What do you mean by "very little"?
    Would 0.000000001A be sufficient?
  7. Aug 29, 2009 #6
    You could place an very strong resistor (like in a voltmeter) on the circuit
  8. Sep 1, 2009 #7


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    for a motor rated at 12V but i want to run 96V or higher to it with little to no amps at all.
  9. Sep 1, 2009 #8


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    do you have any diagrams or pictures?
  10. Sep 1, 2009 #9


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    any diagram or pictures?
  11. Sep 1, 2009 #10


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    Staff: Mentor

    You can't run a motor with no amps and you can't apply a larger than nominal voltage to a motor without increasing the amperage.

    The suggestions (like adding a resistor) will just mean wasting power at the resistor and still supply 12 V to the motor itself. Ie, if the motor pulls 1A and you size a resistor for 84V of the 96V, you'll get 12V and 1A (for 12 watts) through the motor and 84V, 1A and 84 watts through the resistor, accomplishing nothing except wasting energy.

    Why are you doing this? What are you trying to accomplish?
  12. Sep 1, 2009 #11
    Russ is correct...and is describing a voltage divider...but limitng the current to an arbitrarily small value will not provide the POWER required....not a good idea for general use....
  13. Sep 1, 2009 #12

    any load on a circuit (motor, lightbulb etc.) is a resistor, you can buy a variable resistor at a science store. Use Ohm's law to calculate what resistence you want and buy one. But I do'nt see what the point of doing this is. If you want to run a motor why would you not have current running through it?
  14. Sep 2, 2009 #13


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    ok here is a quick picture. the part i circled in red are the solenoids that i want real little amp running through them but still getting the same voltage

    Attached Files:

  15. Sep 2, 2009 #14
    are you concerned that some of your components won't be able to handle the amount of current that your supply CAN deliver? if so you you're thinking about it the wrong way..... alternatively - if you've got your solenoid coil in series with a motor...... I guess I should wait for the diagram to be approved before trying to guess.
  16. Sep 2, 2009 #15
    I dont think your circuit is complete.
    Is the motor supposed to have current running through it?
    Sorta lost on what you are trying to do. You gotta have some
    current to turn the motor over.
  17. Sep 3, 2009 #16
    If you want your engine to run faster wire your batteries in series instead of parallel you will get more volts, and that will give you more current through the engine. However, depending on how much extra power you are giving it it may overheat etc. so be careful.

    Here is a link explaining the difference between parallel and series batteries.

    If that is even what you want to do I don't think anyone really knows anywho so I took a shot.
  18. Sep 4, 2009 #17
    You need current to flow through your motor, that is how it makes magnetic fields resulting in torque.

    If your looking to limit your current so that you don't destroy the motor by applying to much voltage there are many ways of doing that. Unless your particularly attached to this power source you should just switch to a voltage closer to the proper rating for your motor.
  19. Sep 4, 2009 #18
    Well there's you're problem! You've only got one squiggly line connected to the motor.
  20. Sep 4, 2009 #19
    you say you are connecting motor to a circuit, it means you are connecting load to circuit. if the load is present you must have current. and all the motor are rated in power (Power = current × Voltage) if the current is zero your power is zero, you can't run the motor. and also in your picture you are connecting your solenoids in series. in series connections the current is same so all your solenoids will have the same current as your motor.
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