The Secrets Of Back EMF

[onepower]

smoky2

i believe the criteria was "in a vacuum"
meaning there is nothing with the particle, for which heat to be converted from motion (i.e. friction, etc.)
that makes the experiment a purely electromagnetic interaction and will hold irrespective of temperature, within the limitations of the system.

Indeed, superconductors do not generate heat either and repel all magnetic fields regardless of there polarity.
https://theconversation.com/how-do-superconductors-work-a-physicist-explains-what-it-means-to-have-resistance-free-electricity-202308

AC

[tinman]

author=joellagace link=topic=19421.msg575455#msg575455 date=1679437897

When the current is turned off, the magnetic field collapses, which generates a voltage spike known as a back electromotive force

No. Back EMF is produced when the current starts to flow through the inductor. It is the self induced current produced while the magnetic field is building in the coil.

in the opposite direction of the original current

No again.
When the current flowing into the inductor is cut off, the magnetic field around the inductor will collapse around the coil, and produce a current flow in the same direction to the original current flow. This is inductive kickback or flyback, not Back EMF.
The current will continue to flow in the same direction. Only the voltage is inverted across the coil.

By using this feedback loop, you are essentially increasing the efficiency of the system and allowing it to output more power than what was originally put in.

Would love to see this--with accurate measurements.

It's important to note that this doesn't violate the laws of thermodynamics

Right after-->

allowing it to output more power than what was originally put in

[joellagace]

LOL I hit a nerve again! 

[fxeconomist]

When the current flowing into the inductor is cut off, the magnetic field around the inductor will collapse around the coil, and produce a current flow in the same direction to the original current flow.

So, let me see if I understood the difference straight.

Say we have a circuit. To the left, power source. The center has an up/down alligned inductor. The right side has the load.

Inductor responds with a kickback that is in the same direction. If current say, flows up (+) to down (-) in an inductor, kickback current will come out from the down side, continuing the initial direction, thru the load, to return to the up side.

Now we replace the inductor with a capacitor.

Capacitor discharge responds with current in the opposite direction. If current flew up (+) to down  (-), capacitor discharge would flow backwards, from the up side continuing that way towards the down thru the load.

Am I right ?

[forest]

Describe it in schematic to allow all understand