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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
    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.

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      #3
      I thought they were the same thing.
      Master Electrician
      Electrical Contractor
      Richmond, VA

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        #4
        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.
        I live for today, I'm just a day behind.

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

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            #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
            It depends on what the meaning of "is" is.

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              #7
              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.

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                #8
                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.
                It depends on what the meaning of "is" is.

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                  #9
                  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, 11:57 AM.

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                    #10
                    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
                    (All code citations are 2017 unless otherwise noted)

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                      #11
                      Don has it. FLA is a tested repeatable value, RLA is totally subjective and essentially meaningless, except in context.

                      What I mean by that is that there is nothing useful that can be done with RLA values unless you are comparing them to a know value or previous value. For example: yesterday the RLA on this motor was 5.3A, today the RLA is 7.9A, therefore today there is more load on the motor.
                      __________________________________________________ ____________________________
                      Many people are shocked when they discover I am not a good electrician...

                      I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

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                        #12
                        thank you for all your responses they were very helpful and informative.

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                          #13
                          Originally posted by don_resqcapt19 View Post
                          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.
                          You are not permitted to use the nameplate FLA or RLA for sizing short-circuit and ground-fault protection of motors unless the motor is built for speeds less than 1200 RPM or high torques, or for multi-speed motors. NEC 430.6(A)(1) requires the use of the full-load current (FLC) values listed in Tables 430.247, 430.248, 430.249, and 430.250.
                          Jason Rohe, P.E.

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                            #14
                            FLA Vs Running Amps

                            Whats the relationship between motor turns to amps?
                            For example: How much more amps would a 14t draw
                            than a 27t? or 1 less turn will increase amps by how much?

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                              #15
                              Originally posted by jrohe View Post
                              You are not permitted to use the nameplate FLA or RLA for sizing short-circuit and ground-fault protection of motors unless the motor is built for speeds less than 1200 RPM or high torques, or for multi-speed motors. NEC 430.6(A)(1) requires the use of the full-load current (FLC) values listed in Tables 430.247, 430.248, 430.249, and 430.250.
                              If you will read my post again I thing you will find that I said to use the nameplate value for the overload protection and the "table" value for the conductor sizing and short circuit and ground fault protection. Maybe my use of the word table in quotes was not clear, but it was intended to mean the tables at the end of Article 430.
                              Don, Illinois
                              (All code citations are 2017 unless otherwise noted)

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