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- Chris will be leaving for Europe soon. If you’re interested in getting together, here are the days he’ll be there:
- Berlin, April 5th and 6th.
- London, April 19th, 20th.
- The London meetup will be at the Yorkshire Grey (2 Theobalds Road WC1X 8PN London) at 6:30 pm on April 19th.
- Watch @chris_gammell‘s twitter account for any last minute updates/changes.
- Callers!
- Trevor
- He works on wholesale electricity and was wondering about how they change voltages on generators. Chris eventually started talking about different taps on the windings, but that could be wrong still.
- Trevor is also interested in DSP
- Chris suggested a theoretical book by Oppenheim.
- Dave mentioned the free online DSP guide.
- This is in hopes of hacking Zwave devices.
- Get in touch! Either correct us in the comments below or talk to Trevor directly on Twitter: @trevorstweeting
- Todd
- Sam
- Wavetek 27xt
- He was asking about whether to start a kickstarter with a friend and whether he can focus on a problem that is sufficiently technical.
- Chris recommends the book “Scale”
- Arsenio
- Arsenio called in to our first callin show about his rocket. There was an issue with i2c layout and the library. He has since gotten a 1054Z at Dave’s recommendation. And has shipped off his first board to OSHpark!
- He’s having issues with spiders in the workshop. Not as big as the one Dave had in his workshop a few years back.
- Dave recommended trying something like an ultrasonic cockroach repeller. Chris recommended asking Tim and Greg from Backyard brains who have been on the show before.
- Chris
- He’s working with a battery powered ATTiny 84 board that controls an RC boat. Recently switched from a linear regulator to a switching power module…and started blowing stuff up.
- Dave predicts that it is SCR Latchup on the logic. He has made a video about that before.
- This could possibly be solved with an N-channel mosfet controlling power distrbution to the rest of the board.
- Intel news
- Andy Grove passed away.
- Intel is toning down their process jumps, indicating a shift in the predictive power of Moore’s law.
- William
- The Fried Circuits USB tester has steadily added features, but he’s not sure how to get more resolution at the low end. This is a dynamic range problem.
- Current chip is the INA219, also has been looking at the INA169
- The new USB C version requires 24 super narrow pitch pins and does not allow for any breaks in the line because of the high speed signals.
Thanks to everyone who called in! We’ll continue to refine this type of show and keep trying to answer your questions!
Generators regulate the reactive power they create or use by varying the DC rotor current called the excitation current. This is referred to as over-exciting or under-exciting the generator.
The frequency is dictated by the rotational velocity of the rotor which is controlled by an engine or stream …etc. In a power company the frequency of the generator must be matched in frequency and phase of the grid before it comes on line which is referred to as syncing.
Totally uneducated comment here but current in a permanent magnet generator is determined by the load so supplying more current would require more throttle to maintain the same rpm. But in a generator for an AC system you need a fixed voltage and frequency the frequency is controlled by the rpm the excitation of the field windings regulates the voltage this would be analogous to varying the strength of the magnets in a permanent magnet generator.
This is just my makes sense to me explanation I may be wrong.
On the single-wore transmission line, Dr Karl tells a story about when the telegraph line crossed Australia it did not need an earth wire (due to all the iron in the red dirt). Couldn’t find a source for the story but I’ve asked him on twitter just now.
This follows a power/grounding type referred to as SWER (single wire earth return), not specifically because of the iron in the soil, but that does help over longer distances.
The single wire transmission is still used today, and for example is how Basslink (the currently broken connection between Tasmania and Victoria) works. Basslink coincidentally is also one of the longest underwater power transmission cables so as BGDWIE says, its used for extremely long cables so to reduce costs.
Should rename call in shows to “You know?”
Is Dave really moving to the Altium office?? And thats not a April fool???
When does Dave say he’s moving to the Altium office?
Also, does anything, including ultrasound, work on getting rid of crickets?
Finally, Quora has a lot of good questions/answers on Power Factor, lead/lag, etc. ex:
https://www.quora.com/In-an-industry-consisting-of-inductive-loads-why-is-it-hard-to-improve-the-Power-Factor-particularly-at-low-loads-What-is-the-best-solution-to-improve-the-Power-Factor
Re Dave visiting a power station, what about the Snowy Mt. Hydro, Tumit…..make a nice weekend away.