Transformer Design Question, Air gap in core between primary / secondary?

[Jon.boston]

I'm looking at designing a transformer that has a split core. Between
the primary and secondary is 1/8" gap filled of plastic material. I
need to get about 20VDC @6Amps out of the secondary side. I would
like to keep the primary voltage low for saftey reasons, 1:1 ratio.
This transformer is being used to couple power between the 1/8"
plastic wall.

(1) Is there any easy way to figure out the loss in effeciency due to
a gap in the magnetic core material connecting primary and secondary?

(2) What is the size difference in the overall transformer if it were
designed to run at (a) 60 HZ, (b) some higher frequency (10Khz?)

(3) If I wanted to run at a higher frequency than 60KHz how could I
generate the switched DC on the primary? I have 20VDC could I just
put a big FET in and switch a square wave in at the higher frequency
or would it help to knock down the high frequency components? Any
clues on how to aproach a DC to AC -> primary would be useful.

Thanks,
Jon

 

[Luhan Monat]

I'm looking at designing a transformer that has a split core. Between
the primary and secondary is 1/8" gap filled of plastic material. I
need to get about 20VDC @6Amps out of the secondary side. I would
like to keep the primary voltage low for saftey reasons, 1:1 ratio.
This transformer is being used to couple power between the 1/8"
plastic wall.

(1) Is there any easy way to figure out the loss in effeciency due to
a gap in the magnetic core material connecting primary and secondary?

(2) What is the size difference in the overall transformer if it were
designed to run at (a) 60 HZ, (b) some higher frequency (10Khz?)

(3) If I wanted to run at a higher frequency than 60KHz how could I
generate the switched DC on the primary? I have 20VDC could I just
put a big FET in and switch a square wave in at the higher frequency
or would it help to knock down the high frequency components? Any
clues on how to aproach a DC to AC -> primary would be useful.

Thanks,
Jon

Just for starters, the larger the transformer is physically, the less
effect that 1/8 inch gap will have. Transfering power in this way is
not unknown, but you may have to put up with some loss.