[Prev][Next][Index][Thread]

Re: Solid state TC working! But.




-- BEGIN included message

Greetings all,

Malcolm wrote:

>     The resonance(s) experienced with the flyback transformer
>are mostly due to the high inter-winding capacitances experienced
>with the layered winding and also capacitance to the core. In my 
>experience these cores are mostly 3C3/3C6 (Philips numbers) material 
>and are rather lossy at high frequencies.

these inter winding capacitances, leakage induction and resonances are
also a major bummer with the output transformers - resulting in massive
ringing. Why can't we buy perfect transformers from the shop were we
can get a point mass and the light inextensible string?

>It is usual practice to gap cores 
>in SMPS circuits to prevent core saturation due to various conditions 
>that can arise. The primary inductance should be measured with the 
>core in its final (gapped?) condition.

I got the impression that some SMPS circuit topologies used gapped
core and some such as this half bridge used ungapped cores.

I use ungapped cores. A gapped core will need a lot more turns for
the same primary induction. I rely on electronic current limiting to
deal with any unexpected saturation. Of course any transformer will 
saturate if the frequency is pushed too low. (except aircoils).

Have fun.

Alan Sharp (UK)

-- END included message