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Thread: FLA Vs Running Amps

  1. #1
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    FLA Vs Running Amps

    Does anyone know what is the difference between full load amps and running amps is? or where i can find the definition for the two?

  2. #2
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    Quote Originally Posted by Orerofsirhc View Post
    Does anyone know what is the difference between full load amps and running amps is? or where i can find the definition for the two?
    When a motor gives its full rated out put power, the amount of current is called the full load current.
    or
    The maximum current amount which an equipment is designed for it to operation in a special condition.

    When a motor is running at its normal speed without its maximum load, the amount of current is called running current. Or Running current is always at normal motor operation.
    "Imagination is more important than knowledge."

  3. #3
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    I thought they were the same thing.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  4. #4
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    Full load amps is what the motor will draw at its rated voltage, speed, frequency and horsepower. change any of these and your amperage will now be running amps.

    Running amps can be the same as full load amps but the conditions of the power source and load determine the actual amps and are almost never the same as the conditions used to determine the full load amps.

  5. #5
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    I've always been under the impression that FLA is the same as MCA which are the running load + 25%.

  6. #6
    I agree with Ham's explanation. If you had a large HP motor on a large saw blade, just sitting there idling, not under load,, that would be your running amps.


    Now run a big log through the blade and start cutting. The amperage might double. That's your Full Load Amps

  7. #7
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    Quote Originally Posted by mcclary's electrical View Post
    Now run a big log through the blade and start cutting. The amperage might double. That's your Full Load Amps
    No that might be FLA but much more likely it would be RLA.

    As kwired said

    Full load amps is what the motor will draw at its rated voltage, speed, frequency and horsepower.
    While pushing the log through you could, and likely will exceed the HP rating.

  8. #8
    Quote Originally Posted by iwire View Post
    No that might be FLA but much more likely it would be RLA.

    As kwired said



    While pushing the log through you could, and likely will exceed the HP rating.



    That makse sense. My example was really poor for a technical discussion. In my example,,,the current being used would eb proportional to many other factors such as speed of feeding log through and alot of others. In other words, if fed to fast, you would start stalling motor and getting more towards locked rotor currents. There can be a huge difference between the two.

  9. #9
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    IMO FLA is an ideal number that will rarely be seen in the field, we use it only to size the OLs.

    Few applications require the specific HP the motor is rated for.
    Last edited by iwire; 04-24-10 at 11:57 AM.

  10. #10
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    The running current is exactly that...the current that the motor draws when running and is a variable number based on the applied mechanical load. The FLA is the nameplate amps for the purposes of overload protection and the "table" amps for the purposes of sizing the motor circuit conductors and the short circuit and ground fault protection.
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

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