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Flywheel Effect on a Stationary Diesel

  1. Mar 22, 2007 #1
    I'm not an engineer. Unfortunately, my irrepressible brother has somehow coaxed and cajoled me into tinkering with alternative energy - à la vegetable oils, ethanols, etc - and now I'm hooked. I'd love to have one of those Lister Cold Start twin cylinder stationary diesels to play with.

    I have a 1500cc Kubota diesel and a 10k generator head out in the workspace. I've got a scrap metals dealer down the road, my tig set up and ready to go, a fairly complete little machine shop at hand, and membership in about a dozen relevant forums - and am about ready to get moving.

    I'm hoping that someone might offer a basic primer on the function of flywheel effect in this very specific diesel application.
    Stationary engine
    Constant RPM
    Fluctuating load
    Mechanically governed RPM

    There is much talk about varying amounts of flywheel mass used on those old Lister stationary diesels - the single cylinder models use two flywheels of 275 to 300lbs each! What would be the effect of more/less flywheel mass on a more "conventional" genset, my four cylinder 1500cc Kubota for instance?

    Would greater mass be incompatible with the engines standard governor? Would ANY greater flywheel mass be beneficial to a stationary genset (since there is no weight/performance tradeoff to be concerned with?) How does any benefit to performance affect engine wear/longevity or other factors?

    And... as long as I'm here, among cooler heads, is there really any rigorously scientific basis for the (small but growing) interest in these old technology Lister CS engines? That is, are there valid reasons for opting for one of these beasts (specifially for an alt/fuel genset) in preference to the newest offerings - say, my brand spankin' new v1505e Kubota diesel?

    Thank you very much for any illumination on this.
    Last edited: Mar 22, 2007
  2. jcsd
  3. Mar 22, 2007 #2


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    Science Advisor
    Gold Member

    The main effect of flywheel mass (or more correctly, inertia) is load acceptance. A heavier flywheel will be more resistant to load step changes (and thus maintain the electricity output at its required frequency), but if the speed does deviate, it'll take longer to return to its desired value.
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