Just got a review of my books via DM > you get just about every single fact I know anything about wrong, from the very small things to the very big things, and I have to assume you get all the things I don't know much about wrong, too. This was presented as friendly feedback.
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3/ One typical type of three phase motor (the kind I've got on my milling machine) has a stator with three sets of electromagnets, and one rotor. The three electromagnets (or, more generally, 3n) are wired in banks to the three live lines, which are 120° out of phase. >>>pic.twitter.com/6ISBCztlz1
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4/ When the A magnets are energized they apply torque via electromagnetism to the rotor. Then the As are demagnetized and the Bs are magnetized and the rotor (a) keeps rotating because of inertia, and (b) is drawn towards the new energized poles. Then B demagnetized + C ...
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5/ This is why you can accidentally wire a motor backwards and have it rotate in reverse!
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6/ If you don't have 3-phase power but have 1 phase 220 V you can wire one leg to A and one to B and nothing to C. You then have to give the rotor an initial kick, either by hand or with a starter motor engaging with a rubber drive pulley, but once it's rotating it will >
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7/ Engage with the A electromagnets, then then B electromagnets. Timing is wrong bc the phases are 180° apart, not 120° apart, so - I THINK - the motor will run at 50% higher speed during this arc. Then it uses inertia to coast past the C electromagnets and back to the A set.
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8/ Yeah, the fact that I'm getting criticized for having my characters use real-world hacks when the Approved Methods™ don't work is amusing. I did it to show the Aristillus expats as tinkerers with a can-do attitude and old school skills. https://twitter.com/PWilliamKitty/status/1210938691457372161 …
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9/ What else? Ah, my DM friend also criticizes me for having Darcy use a nitrogen flush as a last-ditch approach to empty the water tanks on the Wookie. "This won't work; you need ulage rocket motors." First, I intentionally did not give the Wookie ulage motors to MAKE IT HARD
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10/ Second, the nitrogen system was present in the Wookie bc it was a converted oil tanker and I wanted to show for stylistic / plot reasons that a lot of hardware was cobbled together / repurposed in a crapsack world by tinkerers with a can-do attitude.
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11/ Third, I wanted a hack solution that would solve the problem, but create a new one - less than total purging of the water tanks, which then requires the SECOND hack, which was ditching on-deck cargo.
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12/ Fourth, I am pretty sure that pressurizing a tank from above - even without a membrane to separate liquid from gas pressure, as is done in some cases, WOULD scavenge a noticeable amount of liquid. based on (a) my knowledge of the tuned exhaust systems of 2 stroke engines
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13/ (b) conversations on the topic with my friend Geo (PhD, MIT) re a variety of topics including 2 stroke engines, fluidized beds, and his father (also a PhD in MechE) on using engineered turbulence to adjust dispersal of atomized fluids in internal combustion cylinders
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14/ Now, it could be that I'm wrong about scavenging liquid from a tank with pressurized gas in 0 g. I did the best research I could. ...but given that my interlocutor told me point-blank that you can't run a 3-phase motor on 1 phase WHEN I'VE SEEN IT DONE, I'm not convinced.
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15/ To quote him back at him "you get just about every single fact I know anything about wrong, from the very small things to the very big things, and I have to assume you get all the things I don't know much about wrong, too."
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16/ A third person tags in to say "that thing your interlocutor assures you is impossible, and thus you're wrong about everything? I've seen it with my own eyes". https://twitter.com/libertylineman/status/1210944219138969600 …
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17/ Well, to be fair, I do try to write "hard" SF. The only zero-reason-to-think-it's-possible tech I intend to have is the AG drive. https://twitter.com/jabocka/status/1210944013441884165 …
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18/ For those curious on scavenging cylinders or tanks, here's one place to start https://en.wikipedia.org/wiki/Scavenging_(engine) …
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End of conversation
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