On Wed, Nov 4, 2009 at 8:19 AM, Michael Holstein <michael.holstein@csuohio.edu> wrote:
Well, they say it's a Cat unit, so probably one like this : http://www.cat.com/cda/components/securedFile/displaySecuredFileServletJSP?x=7&fileId=1081064
How long can they go on those 3000 gallons under their current load?
That engine is rated to consume 70.9g/hr at 50% .. so using a conservative estimate, I'd say about 42 hours.
Wouldn't the conservative estimate be 21 hours? (3000 gallons, 142 gal/hr at 100% load); you'd get more hours out by guessing at what fraction of full load the generator is running, but anything longer than 21 hours is fudge-factor guesstimate based, and not to be counted on.
The mildly conservative estimate is 21 hours minus the guaranteed turnaround time for your fuel vendor to show up, minus some more fudge factor to allow for someone to actually hook up and actually refuel, etc. The paranoid conservative estimate is more complex; you have to assume you call the primary vendor, they don't show, and then you have to call your backup(s). If you have a three hour guarantee in the contract, you have to remember that this can still represent some scrambling by your vendor, and if you're lights out, it's quite possible that others are as well, and hospitals and city hall might rate as more urgent. It's also possible that the truck'll have a flat, mechanical problems, or try to rush through the railroad crossing about to be rendered unpassable by a slow-moving freight train. It'll probably take you an additional hour to panic and call your backup supplier; now you are a bunch of hours shorter on capacity than you thought. Of course, a lot of this is simply how you look at the problem. If we're talking runtime-until-dry, yeah, 21 hours. If we're talking a practical number of how long can you go until it's proper for some panic to set in and calls to get made, it's more like half that. ;-) With power: N+1 is usually better than N Best to assume full load when doing math Things will go wrong, predict common failures The best plans are still prone to failure Safety margins can save your rear etc ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.