HN user

generatorguy

341 karma
Posts1
Comments222
View on HN

What are your thoughts on the fact that 90% of the comments here are something to the effect of “there is no sense in personally investing in using Tables since google will shut it down in x years”?

Those are other factors that cause sparks from power lines that are independent of maintenance. sparks are going to occur whether the towers are replaced with brand new ones every 10 years or if they leave them until there starts to be problems and then they go look to see what needs replacing.

Wind, ice, squirrels, birds, snakes and trees are going to cause power lines to fail and create sparks so while perfectly maintained power lines will fail less often failures will still occur. If the world is a tinderbox from now on there is a choice to be made between energized overhead power lines and no risk of fire.

I flew for the first time today in a Cessna 172. I had a hard time determining if I was climbing or descending by looking over the cowling and found myself frequently checking the altimeter and rate of climb steam gauges. To be fair it was mountainous terrain so there was no obvious horizon.

After seeing the foils finally catch on in water sports I have been wondering why there are no foil boats. Great to see someone has made it happen!

I don’t do enough miles a year boating to care about the minor amount of fossil fuels I burn. I would be really interested in the foil tech with gas powered outboard. The foil boat must be must much more fuel efficient with a gas motor?

Never heard it was a software bug? Lack of maintenance allowed tree branches to grow under transmission lines which sag the hotter they get and so on a hot summer day with record system loads one transmission line tripping caused a cascading outage.

Read the Wikipedia page, sure the system operators in MISO didn’t get some alarms but blaming the whole thing on that is pretty lame. There were multiple causes and not Getting alarms was just one of 10 things that went wrong.

I remember some complication with the elevators not working or homing properly at one place so we must have had an outage. it was probably at 3am, scheduled, and with incoming patients diverted. All our tests are and I’m in the electrical room so they all looks the same to me. An actual outage to vital loads would be done once and then you shut the door and walk away as there was never any question that it was going to work.

FYI where I’ve worked the tiers of loads are metered individually and picked up in order of priority and with a check to verify the combined capacity of the generators which are online is great enough to pick up the load. Likewise loads are shed in order if there isn’t enough generation such as one generator tripping.

I don’t really see that much difference between opening a breaker and bad quality power. It is the same sensing and logic in both cases: is the magnitude and frequency of the phase to phase voltages in the acceptable range or not?

I love that the P53 has all the ports on the back so I don’t have cables cluttering up the sides of my on the road desk spaces where I like to keep a proper mouse and mouse pad and a notebook. In the office it’s still nicer too even though it gets hooked up to external monitor and keyboard. No I don’t have a docking station.

Honestly I am struggling to remember an instance where we purposefully plunged an operating hospital in to darkness.

You can test the system’s ability to detect loss of power or poor quality power by lifting sensing wires or injecting out of frequency or voltage range power with a test set, and load pickup and load testing we used a load bank. The actual hospital load is fed through bypass breakers during these tests so if the utility went out we would have to manually operate breakers to disconnect the load bank and swing the vital loads over to the generators.

If I am setting up electrical protection on a generator I don’t put a short circuit on the generator, I show the protection relay what it would see by injecting current and voltage with a relay test set and make sure the relay gives the signal to open the breaker when it should.

Greenfield hospital generation sites are straightforward to open the utility feeds since the vital loads are still fed through the old power system.

ideally the hospital’s generator control system or transfer switch is able to start and synchronize the generators and turn up the throttle until no power is being imported from the utility prior to opening the utility feed, thereby transferring the load from the utility to the generators. This test is only performed when there are no surgeries scheduled and it is cancelled if there are any emergencies coming in all of the sudden. If the test is already in progress incoming ambulances with patients requiring surgery are diverted to another hospital. To finish the test the hospital is synchronized to the utility, the throttle on the generators turned down until no power is flowing through the generator breaker which is then opened.

I’ve built and programmed control systems that do all this with multiple generators, multiple utility feeds, and multiple tiers of loads of different priorities.

Electrical Engineers would determine the settings for the electrical protection of a generator. Mechanical Engineers would determine the settings for mechanical protection of a motor. To operate the equipment beyond thresholds would result in reduced lifespan or immediate and permanent damage to the equipment. If this is what the customer requires they have to specify that to the Engineer so that when the equipment blows up the Engineer is not liable.

Diesel generators for hospitals and water pumps for fire suppression systems are generally set up with very loose settings as it is clearly worse for a patient to die or a building to burn down than to destroy a machine, and this requirement is in the specifications.

Tesla is probably ok since the car is a platform auto updated over the air if China steals the design and can build the exact physical machine and even a version of the firmware it will soon be an inferior version of the product without updates. Kind of like how android phones that don’t get updated are inferior to those that do.

A fisherman I was speaking to in NZ noted on their ships radar lines of trawlers just outside NZ waters presumably doing the same thing - dragging nets between the trawlers and indiscriminately taking everything - or bottom trawling and mowing the sea floor flat and void of life. It is the tragedy of the commons that we can't manage this shared renewable resource. Canada has destroyed their Atlantic fisheries. If they can't manage not to take every fish in the ocean I'm not surprised the rest of the world can't resist it either.

Rotational energy goes up worth both the square or the radius and the speed, so it is much better bang for your buck to have a the mass centered on an outer rim connected to a hub by spokes and spinning really fast rather than just something uniformly heavy. The mass close to the centre doesn’t do anything for you.

The heavier it is also requires bigger more expensive bearings and accompanying system to get the thing spinning in the first place.

I looked at a flywheel that spun at 12,000 rpm. It was going to be located in an underground vault in case it ever got off its pedestal bearings it wouldn’t mow people down.

Like anything that stores energy but doesn’t generate the economics aren’t great.

presumably you can have more than one laser link using the same frequency and bandwidth of light since it is a laser beam just put the next link a couple meters over and they should not interfere with each other at all.