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| tggzzz:
--- Quote from: SilverSolder on April 09, 2021, 09:00:43 pm ---The main issue in North America is the "pioneering spirit" electrical system where wires are strung up among the trees in rural / suburban areas... what could possibly go wrong? :D --- End quote --- So, completely the opposite of this example, 4 miles from the centre of a major UK city |
| Ed.Kloonk:
--- Quote from: tggzzz on April 10, 2021, 01:23:00 pm --- --- Quote from: SilverSolder on April 09, 2021, 09:00:43 pm ---The main issue in North America is the "pioneering spirit" electrical system where wires are strung up among the trees in rural / suburban areas... what could possibly go wrong? :D --- End quote --- So, completely the opposite of this example, 4 miles from the centre of a major UK city --- End quote --- We are world famous here for our y-shaped gum trees on the side of the road. https://www.smh.com.au/national/nsw/ausgrid-accused-of-street-tree-vandalism-by-sydney-councils-20150807-giugg9.html |
| calzap:
I’m curious as to how many data center standby generators are powered by diesel versus propane. In the U.S., diesel is usually more expensive per kw-hr produced than propane, especially because EPA requires such generators to use ultralow sulfur diesel fuel. Diesel has shelf-life issues which require ongoing testing and maintenance, and replacement in some cases. Propane has an infinite shelf-life. Most building codes in the U.S. do not allow liquid propane inside buildings. So, if there is no outside storage area, propane can’t be used. I know of a biological lab near me that became so fed-up with diesel fuel issues with their generators that they switched to propane and have been happy with it. Nice link: https://www.csemag.com/articles/understanding-backup-power-system-fuel-choices/ At my ranch, we have a small (8 kw continuous) backup generator. It’s just big enough to run one well plus a few refrigerators/freezers and a few low wattage items. Forced to run it 4-6 times per year. Longest run has been 2 days. It’s powered by gasoline, and there have been no fuel issues (we use a preservative). It’s in a “dog house” attached to the smallest building on the property. Only real worry is that building is where electrical panels for incoming power are located. In retrospect, I could have built the dog house 10 m away from any building and should have. We have propane available, and dual-fuel installation is on my to-do list … has been for 15 years! Mike in California |
| David Hess:
--- Quote from: calzap on April 10, 2021, 02:46:59 pm ---I’m curious as to how many data center standby generators are powered by diesel versus propane. In the U.S., diesel is usually more expensive per kw-hr produced than propane, especially because EPA requires such generators to use ultralow sulfur diesel fuel. Diesel has shelf-life issues which require ongoing testing and maintenance, and replacement in some cases. Propane has an infinite shelf-life. Most building codes in the U.S. do not allow liquid propane inside buildings. So, if there is no outside storage area, propane can’t be used. --- End quote --- Diesel also has the disadvantage of requiring special containment provisions because it makes a hell of a mess if it spills, which also brings the EPA into it. For this reason and the others you mention, sites which are remote tend toward propane now. For tall buildings, diesel may not be stored at the upper levels so provisions must be made to pump it from tanks near the ground. In some cases requirements are so strict that backup generators of any type are precluded and the only solution is sufficient battery power. |
| David Hess:
--- Quote from: blueskull on April 09, 2021, 08:36:27 am ---Also the control chassis is a mess with f*ing LM723 being abused as OPAMP, and no chip is decoupled properly. --- End quote --- I do not really consider that an abuse, except of course for the lack of proper decoupling. 723s do not make very good operational amplifiers but most applications do not require good operational amplifiers; consider all of the older regulator designs which only use discrete differential pairs for the voltage and current control loops. 723s also have several virtues including a built in reference and provisions for a high current output. --- Quote ---In short, the old design uses old parts, which is no longer made. So the maintenance had to look for alternative parts, and they found an Indian company making supposedly identical old parts for special customers. It turns out the Indians made better parts, faster and more stronger. Different process and die, same paper spec. --- End quote --- That is a common problem even when the same manufacturer changes processes. Unspecified characteristics are unspecified and cannot be relied on. Either test for them or design to handle them. --- Quote ---If not the NRC being dissatisfied and contracted a friend of mine to fix it who contracted me for a small portion of the project, I wouldn't believe how flaky something used as a last line of defense from a nuclear disaster can be. ... And no, the NRC will not take a new control board or new 21st century parts. They insist on all digital control parts must be nuclear certified, and all critical power parts must too. The only leeway we have were non power analog parts, in other words we had to patch on an old stupid design with the oldest technology. --- End quote --- Non-power analog parts are actually more susceptible to radiation damage than power analog parts, but as long as the NRC follows the rules no matter how stupid, they are safe. It is stupid but I am not surprised. The "safest" option when authority is divorced from responsibility is to do nothing, and make sure the blame will fall on someone else, which is why having nothing to do with that sort of project is the best thing to do. I have learned not to even notify them; they are not interested and doing so can create further jeopardy. |
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