Polyester tape around flyback transformer's core

[ysba]

Hi,
Why usually there is a polyester tape placed around flyback transformer core? Is it just for electrical insulation to other PCB terminals or there's some other reason?
Thanks.

 

[FlapJack]

UL requires 2 wraps of insulation on the outside of the windings. Probably for safety from electrical shock.

 

[chuckey]

It could be to stop abrasion of the insulation of the wire?
Frank

 

[ysba]

I think I was not clear enough. I'm talking about the tape showed in the picture, which surounds the transformer's outside.

 

[FlapJack]

The two ferrite cores have to be held together for the transformer to work. The tape could be holding them or the tape was used to hold them together while the glue dried.

 

[EnricoMigliore]

Hi,

the 2 halves of the magnetic core are held together by a liquid resin that gets solid after immersion of the transformer.

The 3 turns of insulation tape AROUND the magnetic core the are required by UL to insulate the secondary from the core.

Enrico Migliore