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  1. Kiwi k
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    Kiwi k New EF Member

    Location:
    Scotland
    any help with this greatly appreciated..the output of a series dc motor when connected to a 230v supply and running at 1320 rev/min is 3.5kw. the supply current for this loading is 20.5A

    1.calculate torque developed
    2. Operating efficiency
     
  2. Pete999
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    Pete999 Trusted Advisor

    Top Poster Of Month

    Location:
    Northampton
    Far to early in the day for questions like this LOL
     
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  3. DAvid Prosser
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    DAvid Prosser Regular EF Member

    Location:
    UK
    τ = (I * V * E *60) / (rpm * 2π)

    E = Pout / Pin

    You have all the information you need for these two equations in the question. So just make sure you follow the rules of what order you carry out pressing the buttons on your calcualtor (or by a fancy one you type it all in).
     
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  4. FatAlan
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    FatAlan Trainee Trainee Access

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    Surrey
    BODMAS?
     
  5. Lucien Nunes
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    Lucien Nunes Mercury Arc Rectifier Trusted Advisor

    Location:
    London
    Mechanical power is the product of torque and angular velocity. You have the output power and the speed in rpm so you can convert speed into angular velocity and hence find the torque.

    Efficiency is the ratio of output power / input power. So again use the stated output power and find the input power from current and voltage.

    If you want further guidance please show your working so far...
     
  6. DAvid Prosser
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    DAvid Prosser Regular EF Member

    Location:
    UK
    BIDMAS
     
  7. FatAlan
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    FatAlan Trainee Trainee Access

    Location:
    Surrey
    Brackets, Of, Divide, Multiply, Add, Subtract. What I was taught about 35 years ago but I'm sure a mathematician will correct me.
     
  8. DAvid Prosser
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    DAvid Prosser Regular EF Member

    Location:
    UK
    Brackets, Indices, Division and Multiplication, Addition and Subtraction.

    Same thing.
     
  9. FatAlan
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    FatAlan Trainee Trainee Access

    Location:
    Surrey
    Bod sounds better. ;-)
     
  10. Vortigern
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    Vortigern Electrician's Arms

    Location:
    England
    Business Name:
    F.H. Electrical
    Brackets, Ordinances (powers) as I was taught it.
     
  11. telectrix
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    telectrix Scouser and Proud of It Trusted Advisor

    Location:
    cheshire/staffordshire
    Business Name:
    Telectrix
    better still, get someone else to work it out. :mad:
     
  12. Kiwi k
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    Kiwi k New EF Member

    Location:
    Scotland
    thanks everyone for the help :)
     
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