Guru
Joined: 07/11/2007
Location: AustraliaPosts: 1904
| Posted: 12:48am 16 Mar 2017 |
So I grabbed the 3KW Aerosharp choke I had and unwound it.
Its quite a job but fortunately the 3mm wire is stiff enough to push it through the slot.
The first hurdle is to undo the clamping bolt, the nut only budges after it has been persuaded with a little blow torch
.Then I ended up with this:
900gram of scrap copper wire and a core with an opening of 70 x 16mm.
The choke as it was is is no good for the rather high primary currents I expect on my inverter.
So I rewound it.
20 sq mm cable just fits 16 times into that slot. This gave me me 4 turns of 80mm sq. (4 x 4 in hand)
Now it looks like this:
The rather unorthodox winding style was because the only way I could fit the wire was to push it through from the same side, using no cross overs.
As shown its connected for 4 turns but by opening one side it could be 8 turns of 40 mm sq. (2 in hand).
Tomorrow might be a chance to see if it works any different from the ferrite chokes I have been experimenting with so far.
I hope the core is laminated from a continuous strip - I did not remove the insulation to see if it was a split C type core. The laminations are very thin though.
Klaus