I need to gap a core, specifically, taking 3mm off the centre pole of an
RM12 core (or 1.5mm of each half).
I could use spacers to gap the whole thing - which would be easy - but
if grinding isn't too hard, I'd prefer it. Total quantity < 50 cores.
Anyone done this?
Cheers
Use transformer tape at 1.5 mils and gap the entire core. You end up
with the same gap as twice the number on the center pole. and no, it
does NOT affect coupling to not have one mating face. The whole reason
you are gapping it IS to "affect coupling".
You tape off one core face. It is easy to trim with a nice scalpel.
You can get 1 mil and 1.5 mil transformer tapes in short qtys no
problem.
Trimming out 50 core faces doesn't take that long, and the number is
exact because the tape is consistent.
You then have to remember to pair an untaped core and a taped core
together in the build.
Grinding works, but you can call Farnell or the like and get them
already gapped too. So you could find and buy 100 pre-gapped cores and
have 100 sets to use. As to the grinding, abrasive cloth on a rubber
stab works, but precision is a grind-test-grind-test matching and culling
hand operation. Some transformer houses might sell you a gapped core.