Kathy Loves Physics – Why the U.S. uses 120 volts and not 220 volts
An evening pause: Here’s a bit of technology history that still affects us daily.
Hat tip Tom Biggar.
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She has the history correct. I know she is explaining to a general audience about current, voltage, frequency, and 3-phase transmission. One nitpick, on her equation for the line voltage of a 3-phase Wye, it is 1.73 not 1.72. ;)
Another small nit – she starts off explaining about Edison and DC, but then starts talking about transformers, but didn’t mention that they only work on AC.
On Mars, we might start all over again, maybe with superconducting DC that can send information for less birdnesting.
When living in the UK. 220V. Electric blankets: nope.
I wonder about the 60Hz thing: If it were double that, your transformers could get away with being smaller/lighter. I think Navy ships use different voltages/frequencies for losses and efficiency. (They have (450, 120) V lines at (60, 400) Hz). The 400 Hz banks are for powering various systems related to the weapons systems.
She is an amazing teacher
MadRocketSci,
The old standard is 4180v 60Hz for a ship’s main electrical bus, and the new Ford Class Supercarriers are using 14kv. I know that since I had to design a substation to provide ship to shore power to switch between the two.
Yes the Navy uses 400Hz for most large motors and generators on a vessel. You can have smaller transformers with 400Hz compared to 60Hz, the less weight the better on a vessel. When you have a higher frequency, the size of the iron core and wiring of the transformers decreases.
Interesting topic but hard to watch.
I’m guessing she is/was a teacher/lecturer used to speaking at the front of a large classroom/lecture hall.
In such a setting the vocal projection and hand movements work.
She’s not the only YouTuber to forget that typical YouTube camera distances are akin to speaking to someone a few feet away.
Just talk, and keep your limbs under control. And avoid the facial close-ups, we aren’t your dentist! (at least she doesn’t do that)
And when doing a video you can leave the photo or chart on screen and continue to talk. There are excellent YouTube vids where the speaker is not seen at all (Drachinifel’s naval history vids come to mind). That way there is more time for the audience to view those charts and photos
Rant complete!