AC Motor Nameplate

Motor name plate is the introduction or certificate for an electric induction motor.We can know in detail about an electric motor with refer to the nameplate.It same like our identification card or passport.All detail information about that electric motor we can get from this nameplate.

These parameters are then print onto the motor nameplate,it state a basic definition of what motor have received.Manufacturers often include additional information to further define a key motor features.

From motor name plate we can determine many things.All information is very useful when we perform installation,power supply termination,troubleshooting and repairing jobs.

It’s can make the maintenance person or electrician more understand and recognize exactly what type of motor their dealing during installation or repairing jobs.

Electric Motor Nameplate

There are some usual important categories are on the motor name plate,i discuss this 6 parameter in separate blog post :-

For example,when we want perform installation jobs for electric motor,first we must confirm from motor name plate the information such as the motor connection ( star or delta ),the suitable voltage and full load ampere.From that information we can calculate the cable size,circuit breaker size,suitable voltage and type of motor stater.

Application for motor nameplate

It can save our time and cost when we get a correct preparation for installation job of electric motor.One more example,when we troubleshooting a electric motor and detect the bearing is quite noisy sound,that mean we must replaced the bearing.

But how we can know the bearing size?we need to order the new bearing for replacement.We cannot dismantle that motor for know the bearing size because it on running.The solution is from motor nameplate.It state the bearing size for that motor.We can easily know the bearing size without dismantle the motor.

From this example,i want to highlight why the name plate of electric motor is very useful and important.Please understand all information state at motor nameplate.Don`t worry,i explain detail about 6 major information at motor name plate in my next post…


  1. mohandas says:

    dear sir

    Can i know about what is the difference between the

    ELCB and RCCB.

    thank you

    • Dear mr mohandas,
      ELCB : earth leakage circuit breaker : it refers to voltage operated devices that are no longer available in market.
      RCCB : residual current circuit breaker : It trigger the leakage in current operated using current transformer.It is the best way for protection.

  2. mohandas says:


    How to know starting capasitor and running capasitor?
    What is the deference both?

    thank you

  3. mohandas says:


    How to connect single phase motor coil connection?

    thank you

  4. I would suggest to include locked rotor current,no-load current,noise level at no-load and full load,vibration level,bearing sizes,sizes of capacitor required for pf correction and shunt capacitor method of starting,starting time in DOL and star-delta methods,too in the nameplate. Instead of insulation class ambient temp and maximum temperature will be more useful. The vendors may not give technical literature with the purchase of every motor and most users may not know the web address of manufacturer from whom information could be obtained.

  5. Similar to duty S1,S2 etc is there any classification like AC1,2,3 etc for motors which can affect the temperature rise as well as bearing,shaft etc?.

  6. zonaid hasan says:

    Hello,i am having confusion with the name plate understanding.plz check this name plate first.

    Pout:42*746=31.34 kw.
    and assuming pf=.9 , Pin=Pin:1.73*415*42*.9=27.14 kw

    but Pin<Pout not possible .where have i made mistakes??

  7. zonaid hasan says:

    but still pf is very high(.9).so why still pin<pout?theoritically that is impossible.where are the losses then?

  8. Nikhil Thomas says:

    In which basis, we can categorize mcb,mccb,rccb,elcb,vcb?

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