General > General Technical Chat

"Veritasium" (YT) - "The Big Misconception About Electricity" ?

<< < (397/397)

adx:
I honestly don't know what my transformer idea was now - I'm wondering if I simply messed it up. It had a turns ratio, pressure and current modification. I think it relied on momentum to 'isolate' the turns from each other (within a winding), but not resonant (I thought). There were elastic membranes at each 'turn', it wasn't particularly complicated - just as soon as I got it making sense I was pleased there was a direct equivalent even if it didn't seem to have any obviously practical use, and moved on. I can't see even remotely how it could work now. I can only assume I confirmation biassed myself. Of course a mechanically coupled small and large piston works like a transformer, but that works at DC and is cheating, so wasn't it. I guess a venturi does come close, doesn't isolate (could be made to at AC), but no "turns". Sometimes it's best just to stop thinking!

It reminds me of my "capacitive transformer" I dreamed up years ago - vaguely similar idea of swapping inductive energy transfer for capacitive. Except it needed a magnetic core to isolate the turns so I now have to wonder if that did anything at all either. I did build it though - put some power through it IIRC and it did at least work. But similar to the above it can't be accessed easily (in its case from the days before putting notes and photos of everything on the computer or at least indexable form - and a time when I couldn't conceive of the day when I wouldn't "just remember" where and what everything is!).

Berni:
If you do want to emulate inductance in a water analogy it would be a pump connected to a flywheel.

The pressure (voltage) pushes a flow (current) trough the pump making it work in reverse as a hydraulic motor to spin up the flywheel, then after the pressure is removed the flywheel keeps turning the pump that keeps pushing a flow trough the circuit. The bigger the inductance the bigger the flywheel.

If you then want to turn this into a coupled inductance (for example for building a power transformer) then you would link two of these pump-flywheel assemblies with a common shaft. This way pushing current trough one 'inductor' also spins up the flywheel of the other inductor to drive the pump and produce a flow on the other side. Tho this has the problem of also working with "DC flow" as the assembly will just keep spinning with a steady flow. A more accurate acting example would be to replace the positive displacement style pump with a dynamic type pump (such as a axial flow pump, these pumps produce RPM dependent pressure rather than flow) and replace the flywheel with a rubber band. That way the pump can only turn so many times before the rubber band is making as much torque as the pump can produce at such a flow rate (DC steady stage in an inductor). Then once the flow is removed the rubber band can overpower the pump and start driving it backwards, producing a "back EMF" in that inductor as well as the coupled inductor. In this case the rubber band tension is the magnetic field that can only get so large at a given current, once collapsing returning its stored energy.

At this point water based analogies of electricity start to go a bit too far. But they might help someone picture how an inductor works.

For example the so called "Ram Pump" is an excellent example of a switchmode boost converter done using only water (it pumps water up hill using no external power source):
https://www.permaculturenews.org/2014/04/02/ram-pumps/
It uses the momentum of the water flowing down a pipe as an inductor. Letting the water flow out the end to let it build momentum before suddenly shutting the end off to make the water hammer itself into the value, producing lots of pressure, that then gets rectified by a check valve (a diode basically) to a steady high pressure that is used to push water up a hill.

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version