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Cheoy Lee 76 Alpha

Discussion in 'Cheoy Lee Yacht' started by wdrzal, Feb 10, 2013.

  1. wdrzal

    wdrzal Senior Member

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    In the specs for the Cheoy Lee boat on the splash page the Genset specs caught my eye: (Generator: Onan 32 kW, 60 Hz / Onan 27 kW, 50 Hz).

    MY question is why generators with different frequencys???? 60hz vs 50hz:confused:
  2. K1W1

    K1W1 Senior Member

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    Hi,

    That is probably because the advert was used in the US and elsewhere,

    The same engine might be used , 50 Hz, 27 kW at 1500 rpm, 60 HZ ,32 kW at 1800 rom
  3. Capt J

    Capt J Senior Member

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    This is very common on a lot of the smaller generators......I think they do 2100rpms and 1800rpm's on some of them as well to get the different hertz....... Obviously running at a lower RPM is going to make less power.
  4. K1W1

    K1W1 Senior Member

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    Hi,

    It is not uncommon on big ones either although I am yet to see a 2100 rpm set
  5. Capt J

    Capt J Senior Member

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    MASE generators run diesel Yanmar's and are run at 3600rpms and 3000rpms for 60 and 50hz. Fisher Panda also run's those rpm's on a lot of them. I forget which diesel generator manufacturer ran at 2100 and 1800. But the majority of 5kw+ generators are 1800rpms and 1500rpms
  6. K1W1

    K1W1 Senior Member

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    These will undoubtedly be small 2 pole machines.


    Speed and Frequency do not make 3 phase, it is the construction of the alternator that dictates this. I doubt that there is a alternator manufactured that operates with a steady 50 or 60 hz output at 2100 rpm.


    No argument there, these will be 4 pole alternators.

    Larger machines run by Medium Speed Engines will also be found operating at 1000/1200, 750/900,600/720 for the most part each speed reduction adds a pair of poles.
  7. Capt J

    Capt J Senior Member

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    To answer your question about frequencies. Europe uses 50hz for their electricity. The US and CANADA use 60 hertz. They're not interchangeable. All electronics and most appliances will fry if you go from 50hz to 60hz, if they're designed for 50hz, and if you go the other way around, it's not good either and will burn up stuff.

    A lot of yachts may be produced in one region with 50hz, yet sell in a region with 60hz. With many generators it's a simple matter of adjusting the RPM's to either 1800rpms or 1500rpms, depending on what type of power the boat is setup with. Granted if you turn the same engine/generator 1500rpms instead of 1800rpms, it will not make as much power (kilowatts).
  8. K1W1

    K1W1 Senior Member

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    Hi,

    You can't simply crank the Genset speed up and down depending on where you are located.

    There will be components installed onboard that will not take the change kindly
  9. Capt J

    Capt J Senior Member

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    My statement didn't say for the yacht owner to crank the rpm speed up or down. I was explaining that the factory could change the generator rpm's and hertz to match where it's operating area will be and what electricity it's appliances/systems are designed for, for that region.....