what is the equation for the number of wire turns in a system consists of two co-axial transformer 1

[amirkhan1975]

I have a coaxial transformer coils in order to transfer the power in a wireless manner. I would like to know for a certain power, voltage and frequency how many turns of wire each coil needs. Assume the followings:
Power= 1 W
Voltage= 5 V
Frequency= 300 KHz
Number for turns=???
Also, I have attached the dimensions for the coils. There is a 0.02" air gap between two coils.

 

[MikeHalloran]

It appears that you have drawn a four-piece core set for a rotary transformer, with a cylindrical air gap of specified size in addition to a transverse planar air gap of unspecified, probably zero-ish dimension.

I'm a little fuzzy on how you intend to wind the coils, particularly the outer one. ... but since you have shown zero coil detail, maybe I am misinterpreting what you failed to include in your drawing.


Mike Halloran
Pembroke Pines, FL, USA

 

[amirkhan1975]

The outer coil is manufactured in two pieces to facilitate the winding. I have no question about the winding process. I would like to know how many wire turns I need considering my specification.

 

[VEBill]

Simplest possible starting point: You neen enough turns to provide enough inductance to ensure a resonably high-Z when the secondary is absent, open or unloaded. Otherwise your primary is called a short circuit.

IIRC, the old rule of thumb was to aim for enough inductance to provide an input Z under open circuit secondary conditions of at least ten times the normal operating load.

Disclaimer - this from memory, so double check.

 

[sreid]

http://home.earthlink.net/~jimlux/hv/wheeler.htm