Generators

Discussion in 'General Electronics Chat' started by Mj2020, Jan 21, 2015.

  1. Mj2020

    Thread Starter New Member

    Jan 21, 2015
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    0
    Hi,
    We have new ongoing project in our plant to upgrade the power by adding 2 frame5 generators to the network. Hence, the new generators are designed with 4 poles, 1500RPM. Whereby, the existing generators are designed with 2 poles , 3000 RPM. The frequency is maintained to 50Hz.
    Can someone explains the benefits of increasing the number poles from 2 to 4?
    Why the manufacturer didn't design like to like generator?
    Will that change have negative impact to our network?
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,053
    3,244
    A 4-pole generator operates at half the speed of a 2-pole as you noted.
    It allows the engine driving the generator to operate at a slower speed for quieter operation and longer life.
    It does, however, require the engine to be physically larger for the same power output.

    There is no change on the output waveform or impact on the network (as long as the two generator's outputs are synchronized).
     
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    the four pole generators run at lower rpm, its easier to ballance out vibration at lower rpm, and bearings will last longer. you will have to reduce speed to use the new generators, by reduction gears, belsts, or other means.
     
  4. Reloadron

    Active Member

    Jan 15, 2015
    967
    234
    It works out this way:



    Here in the US where 60 Hz is the mains power frequency my little 4,000 watt gasoline powered generator runs at 3600 RPM and is obviously a 2 pole generator, were I in a country with 50 Hz. mains it would run at 3,000 RPM. Rather than using gasoline if a diesel fuel engine were used diesel engines generally run at much slower engine speeds so the same generator using a diesel engine would likely be a 4 pole generator running at 1800 RPM here in the US. The horsepower of my engine is 8 HP (I think) and regardless of engine speed the amount of HP required to generate my 4,000 watts will remain the same.

    The above quote was taken from here.

    Ron


     
  5. Mj2020

    Thread Starter New Member

    Jan 21, 2015
    3
    0
    Thanks gents,

    Do you think synchronizing the existing generator "3000rpm" with the new generator "1500rpm" will be a problem?
    Note the frequency is 50Hz in both cases.
     
  6. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    50 Hz is 50 Hz. no diff. in syncing them
     
  7. crutschow

    Expert

    Mar 14, 2008
    13,053
    3,244
    Do you have a method for syncing them?
     
  8. Mj2020

    Thread Starter New Member

    Jan 21, 2015
    3
    0
    Yep, through Synch Panel.
     
  9. Reloadron

    Active Member

    Jan 15, 2015
    967
    234
    That would be my question? Sync does not just mean the frequency, it means to me each generators output is 50 Hz (in your case) and they are synchronized in phase as well as the same exact voltage out. Doing this is not an easy task and for small generators just about impossible. If I have a 4 KW generator and my needs grow to 8 KW the best solution is not to add another 4 KW generator unless each is kept isllated, the best solution is to remove and replace the 4 KW generator with an 8 KW generator.

    Ron
     
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