What is the mean of that? Plz help

Discussion in 'General Electronics Chat' started by savage67, Nov 24, 2009.

  1. savage67

    Thread Starter Member

    Oct 3, 2006
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    I ask my supplier about efficiency of my mono phase induction motor.
    he sent me that;
    Efficiency
    eff≥46%
    What ise the mean of that.
    46% is very low.
    isn't it or is there anything i overlooked.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,142
    1,790
    Low compared to what?
    An efficient SMPS -- Yes
    A solar cell -- No
    What were you expecting from rotating machinery?
     
  3. savage67

    Thread Starter Member

    Oct 3, 2006
    27
    0
    it must be between 70%-90%
    isn't it?
     
  4. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    It should be.
     
  5. Papabravo

    Expert

    Feb 24, 2006
    10,142
    1,790
    Why must it be that high? Cheap bearings, high inertia, insufficient number of windings could all explain the discrepancy.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    It's quite unlikely Papabravo. A single phase induction motor would almost always be >70% efficiency when operated within its spec. 80% or so would be more typical.

    To get one under 50% efficiency you would have to practically wind it with resistance wire, that's for any decent sized one (which would have typical magnetics).

    This one in question might be some tiny cheap weird thing but if I received a reply back with >=46% efficiency for an AC motor it would definitely raise an eyebrow. That might be some type of broad spec, ie worse case, but even then...
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    Of course we can speculate until the cows come home, but only the OP can shed additional light on the situation.
     
  8. savage67

    Thread Starter Member

    Oct 3, 2006
    27
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    Hi,
    No additional information. only >=46.
    what is the worst case situation for a single phase ind. motor.
    it may be no load condition?
     
  9. Audioguru

    New Member

    Dec 20, 2007
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    I think you have a very cheap poor quality motor that has a terrible efficiency.
    Even its manufacturer cannot say how bad it is.
     
  10. savage67

    Thread Starter Member

    Oct 3, 2006
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    it is not acceptable. %46 is a massacre . all countries have energy efficiency standarts. this manufacturer can't sell its products to anyone. >= 46 must have another mean.
     
  11. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    apparently there is some kind of communication barrier that must be over come.....


    anyway I believe the >=46% has a pretty broad spectrum, it could mean the motor runs @ 80% efficiency at full load and could get down to 46% efficiency without a load considering that Electric motors operate efficiently when they are heavily loaded – meaning they efficiently translate electricity into work. But when motors are lightly loaded, they become very inefficient and waste electricity.

    this is a really big concern for appliance manufacturers and such for home/commercial appliances that use single phase induction motors, companies such as these >> http://www.powerefficiencycorp.com/product_1p.php << are always trying to develop a way to run these motors more efficiently with lighter loads such as clothes dryers and washing machines....

    My .02
     
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