Guru
Joined: 07/11/2007
Location: AustraliaPosts: 1904
| Posted: 10:33am 19 Jun 2019 |
Yes, I'm fully aware about tight fits
, I had to wreck my first winding attempt because I ran out of hole space 
.So, rearranged the transformers to be similar than your N0 1, then use the 2.5Kw core with the troublesome 85mm hole and modify it for No 2 transformer. It has now a 96mm hole with the removed steel placed on the outside, this cost 50mm sq of core area which = one extra wire turn.
I will use a smaller secondary, 6.8mm sq total, good enough for my battery and usage.
I also plan to use enameled primary wire, not sheathed cable like you.
Just have to get the tiny toroid core ready yet, then the winding fun can begin.
A word of warning for those wannabe warpinverter builders:
1. a set of PCB's does *not* make you a warpinverter - or any other home built inverter type for that matter.
2. these projects stand and fall by procuring the correct transformer(s).
3. I strongly recommend to any newbies tackling the transformer first, before buying *any* other parts.
Its not as easy as it may appear by looking at the pictures from those who have been there, done that.
While a warpinverter scales up easily its probably a waste of time and effort to build one smaller than 4KW total power IMO, too difficult to wind sufficient turns around a small core.
And the big double stack core for my warpinverter weighs around 20kg which has to be wrestled over and over on the workbench to wind a few hundred turns of wire onto it.
That requires tenacity, knowhow, skill and patience to see through, beside requiring a heap of copper wire plus the cores.
Note that I did not mention enthusiasm - its all sheer drudgery
. Unless you can afford to pay somebody to do it for you 
.Only those who successfully complete and get to test their transformers to run reliably are worthy to proceed to the next (purchased PCB) stage of that inverter
. Klaus