Is it worth potting the transformer and PSU caps of my Firstwatt f2

[hugz]

Hey guys

I did a Firstwatt f2 build a while ago. Just adding some final touches now.

It uses a not particuarely fancy transformer, which just has a wrapped thin clear plastic coating around the wire wrap.

An externally hosted image should be here but it was not working when we last tested it.

Would it be worth removing the plastic wrap and soaking the whole thing in glue/epoxy?

For reasons that i cant remember, we raised the resistors and caps off the PSU board. Is it worth epoxying under them to restrict any movement?

Thanks

Hugz

 

[bob91343]

Epoxy is not good. It sets up hard, which isn't good for transformers. Further, you are eliminating any possibility of repair.

If you must, use silicon rubber.

 

[RJM1]

Bob beat me to it.

I wouldn’t pot the transformer in epoxy because of magnetoconstriction (vibrations caused by expansion and contraction of the core which occurs at each change of flux linkage, that is, twice per mains cycle). If you restrict the expansion and contraction of the transformer core this will reduce the inductance of the core and increase heat dissipation. Additionally potting will reduce the airflow cooling the core and increase its temperature. If you want to glue the transformer and capacitors to the board to keep them from moving I would suggest silicon rubber glue which allows for the expansion and contraction. This will also make removal much easier in case of parts failure.

 

[hugz]

Thanks folds. I'll silicone the caps to the board to keep them generally stable. Are you both saying I should leave the transformer completely alone?

Thanks again

Hugz