Flyback core halves clenched together by magnetism?

[cupoftea]

Hi,
We are doing a 40W Flyback with pq20/16 cores.
Its 24vin, 20vout, 2Aout, 150kHz.

We didn't have any core clips to hold the core halves together, and also, we forgot
to put much tape round the core to hold them together, we just used a single piece of
tape all the way round the core halves.
The primary and secondary coils measured ok when we checked.
But we wonder if they will vibrate loose and not be always tightly clasped together?
However, do you believe that the magnetism will actually tend to clench the core
halves tightly together anyway?

 

[D.A.(Tony)Stewart]

To ensure long-term stability and proper functioning, it's generally recommended to use core clips or additional tape to securely hold the core halves together.

 

[cupoftea]

Thanks, yes, though for some quick test-only purposes, would you say its ok to leave it?, since the magnetism (and the residual magnetism) will clench the core halves together? The transformer is flat on the board, so gravity wont be trying to part the core halves. Its just that when ive taken flyback transformers apart after they have been used....the cores are stuck firmly together even though not glued or clamped at that point.

..and i presume this is the magnetism (residual magnetism ) clamping them together?

 

[cupoftea]

..we could just desolder it and put the extra tape on, then put it back, but its in a precarious state, and so we would rather leave it there if poss.

I believe that a flyback transformer, if first held with core halves slighty apart, then when energised, the core halves would actually pull together....its kind of like the relay mechanism, would you agree?