Tweet
Mi sono imbattuto in questa pagina: http://amasci.com/weird/unusual/exper.html
Leggendo, ho trovato interessante l'esperimento "Weird Transformer Effects". C'è una spiegazione logica?
Lo riporto qui:
E ancora più incredibile l'esperimento successivo! Un oggetto di metallo scomparso e riapparso!!! C'è anche l'e-mail del costruttore
Edited by franz5000 - 15/9/2005, 23:21
Leggendo, ho trovato interessante l'esperimento "Weird Transformer Effects". C'è una spiegazione logica?
Lo riporto qui:
CITAZIONE
Weird Transformer Effects
All,
One you can try at home easily and it's paradoxical and bizarre!
I have a toroidal transformer with a primary and secondary. Turns ratio is irrelevant but primary is 6V to secondary 240V (ie 1:40). Now Imagine this setup (this is done with relays so every goes back to high impedance, o/c):
Primary to a voltage source:
________
| |
| |
| |
--------- -------------------------
Secondary shorted by relay:
____________________
| |
| |
| |
------------- -------------------------
Assume that on primary side we have given enough time for transients to die away so that steady current in primary. We then short the secondary. FACT when we do this, no effect on primary side (as you'd expect).
WITH SECONDARY STILL SHORTED. Disconnect primary current. What happens? You'd expect to see a back-emf in the primary? Hang on flux links the secondary too, so you'd see one there too, right? FACT: nothing!!
So what happens when you eventually unshort the secondary (the primary is o/c)? (Eventually could mean seconds, days, weeks, months, years ...) FACT: You see a back emf in the primary!! (Finally!)
A Quick Thought:
1) IF we did see a back emf when we o/c the primary we could violate c-of-e because we flux link two coils. Imagine the primary(s) is an LC tank circuit setup to give us the pulse. We then un o/c our secondary when the current in the primary is steady and pick up that change in flux when we o/c the primary. NATURE won't let us do that.
2) If when we unshorted the secondary we saw no back emf in the primary, where did our electrical work go in setting up the primary current??? It can't have disappeared - another violation of c-of-e.
3) Okay, we saw a back emf. That implies a flux was present => a current was flowing. Hang on, the primary is open circuit!!! The secondary is shorted, there must be current in the secondary BUT the secondary is totally passive (no current sources). WHAT THE HELL KEEPS THE CURRENT GOING! (especially if we unshort days after!)
If there is no current, there is no magnetic field. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
What generated our back emf? I've been talking to some engineer freinds of mine - there is some stress in space apart from the usual em fields.
Please, can we have an answer. Can anybody make use of this phenomenom. This is so easy to replicate.
R. C.
London, Britain - Wednesday, April 21, 1999 at 14:41:28 (PDT)
All,
One you can try at home easily and it's paradoxical and bizarre!
I have a toroidal transformer with a primary and secondary. Turns ratio is irrelevant but primary is 6V to secondary 240V (ie 1:40). Now Imagine this setup (this is done with relays so every goes back to high impedance, o/c):
Primary to a voltage source:
________
| |
| |
| |
--------- -------------------------
Secondary shorted by relay:
____________________
| |
| |
| |
------------- -------------------------
Assume that on primary side we have given enough time for transients to die away so that steady current in primary. We then short the secondary. FACT when we do this, no effect on primary side (as you'd expect).
WITH SECONDARY STILL SHORTED. Disconnect primary current. What happens? You'd expect to see a back-emf in the primary? Hang on flux links the secondary too, so you'd see one there too, right? FACT: nothing!!
So what happens when you eventually unshort the secondary (the primary is o/c)? (Eventually could mean seconds, days, weeks, months, years ...) FACT: You see a back emf in the primary!! (Finally!)
A Quick Thought:
1) IF we did see a back emf when we o/c the primary we could violate c-of-e because we flux link two coils. Imagine the primary(s) is an LC tank circuit setup to give us the pulse. We then un o/c our secondary when the current in the primary is steady and pick up that change in flux when we o/c the primary. NATURE won't let us do that.
2) If when we unshorted the secondary we saw no back emf in the primary, where did our electrical work go in setting up the primary current??? It can't have disappeared - another violation of c-of-e.
3) Okay, we saw a back emf. That implies a flux was present => a current was flowing. Hang on, the primary is open circuit!!! The secondary is shorted, there must be current in the secondary BUT the secondary is totally passive (no current sources). WHAT THE HELL KEEPS THE CURRENT GOING! (especially if we unshort days after!)
If there is no current, there is no magnetic field. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
What generated our back emf? I've been talking to some engineer freinds of mine - there is some stress in space apart from the usual em fields.
Please, can we have an answer. Can anybody make use of this phenomenom. This is so easy to replicate.
R. C.
London, Britain - Wednesday, April 21, 1999 at 14:41:28 (PDT)
E ancora più incredibile l'esperimento successivo! Un oggetto di metallo scomparso e riapparso!!! C'è anche l'e-mail del costruttore
Edited by franz5000 - 15/9/2005, 23:21
)
e sul primario si scarica se lo chiudiamo. 
) succedono cose diverse, inaspettate ... da qui il paradosso.
)
Commenta