Builiding of a complete 6kW PV inverter with MPPT chargers

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wiseguy

Guru

Joined: 21/06/2018
Location: Australia
Posts: 1108
 Posted: 01:50pm 03 Jul 2024

-dex- said  I understand one turn as one complete loop around the core. I also use this with the chokes. The 25uH I provided refers to the value I measured using an oscilloscope. There is definitely some measurement error there, but could it be several uH?

It is not one complete turn around the core if the wire passes through the central hole even as a straight piece of wire with no bends it is 1 turn.  So a current transformer is placed over a straight piece of wire carrying the load current and then it works as designed.  It is a bit counter intuitive to follow when with e cores it has to pass through each core half, or a ferrite rod needs a complete turn.

With the chokes it is similar, each pass through the central hole is 1 turn - yes it loops around the outside and then passes through again - now it is 2 turns etc. Yes I went back and looked at the Blue chokes and they have 14T not 13T    And your big toroidal transformer mains winding has 1 turn too many - fix it lol

Lastly your query can 1 turn make a difference to uH  - yes!
Remember formula L = N x N x Al if Al = 200nH;
13T = 33.8uH,  14T = 39.2uH 15T = 45uH  Differences of 5.4 & 5.8uH for 1 turn
Edited 2024-07-04 00:10 by wiseguy