Problem with Induction

[Bavananth]

Hi!

I have a problem with inducing a voltage using 2 copper coils wound on two separate ferrite cores. When I apply 5Vp-p 5KHz AC to one coil (All winding direction stuffs were considered), can't I expect a voltage about (5Ns/Np Vp-p)at the other coil? I used Np:Ns=1:4.But I get an AC with 0.1V Vp-p at the secondary. I'm confused. What might be the problem? Any suggestions,pls?

I increased the frequency upto 200KHz now secondary is 1Vp-p. Why?

What I'm trying to develop is something like mentioned in the following link
"http://www.cfr.ro/jf/engleza/0310/tehnici4.htm".

to go to the full page"http://www.cfr.ro/jf/engleza/0310/tehnici.htm".

Thankyou!

Bavananth.

 

[Diver300]

You will only get a voltage equal to the turns ratio times the input voltage if all the magnetic flux on one coil goes through the other coil.

That can never happen, so the voltage will always be less.

In a transformer, the coils are very close and it is very difficult for magnetic flux in the primary to avoid the secondary, so the voltage is nearly the theoretical value. It will usually be between 99% and 100% of the theoretical value for a good transformer.

In the drawing you show the coils are far apart. Very little of the flux from the primary will go though the secondary. Also the angle of the coil is set to give very little voltage.

When the railway wheel passes, the flux changes angle, so more flux goes through the coil so there is a bigger voltage.

The coils are not designed to transfer power, so they are bad at tranfering power. They are designed to detect railway wheels, so they are probably quite good at that.

 

[Bob Scott]

I have a problem with inducing a voltage using 2 copper coils wound on two separate ferrite cores. When I apply 5Vp-p 5KHz AC to one coil (All winding direction stuffs were considered), can't I expect a voltage about (5Ns/Np Vp-p)at the other coil?

The magnetic field in a toroid is fully contained. That is the advantage of a toroidal core.

There should be NO magnetism or voltage induced from one coil/core to the other. In order to do that, don't use a core or use a rod for a core.

 

[Bavananth]

Thank you!

Got cleared! Thanks again

Bavananth