Thread Starter

Manjesh Gowda

Joined Oct 19, 2020
83
Hello guys,

I really need your help on this.
I am designing an Inductor which is rated for 50A and 350 Vrms for 85Khz. I want to get 3 inductance value from one inductor so i decided to tap between the points or to use switch to get the required inductance.

I just want to know if my assumptions are right..

Consider ETD 59 core. lets say i make 5 turns to get 14uH and solder both the ends to the bobbin pin (lets consider Pin 1 to 2).
Again I make 3 turns on the second layer (I start from the side where 1st layer winding ends) I solder both the sides (Pin 3 to 4)
Now, if I connect between
1 and 2 I am supposed to get **14uH**(5 turns).
3 and 4 I am supposed to get **5uH** (3 turns)
if i short 2 and 3 and measure between 1 and 4 I am suppose to get **36uH** (8 turns) which makes it in series, I just calculated using ferroxcube tool for respective turns and assumed it would give the same.

Here my questions are.
1) Can i use switches and jumpers between the windings as i said and get the mentioned inductance value?
2) If there is a space on the first layer after making 5 turns, can i start in the same layer to make 3 turns? does mutual inductance come into play in this case?
3) if its right which way is better to do either making 3 turns in 2nd layer or in the same layer?

PS: Here I am doing tunable network where I am reducing the total size of the circuit by doing 3 inductance value in a single inductor.

I would really appreciate if anyone can tell me what to do with this. I can give you more information on this if u need it. Thank you in advance. Waiting for your valuable answers.
 
Just be aware you are going to get transformer action on your other taps in any configuration you use. Think of it like an autotransformer or an isolation transformer. You'll need to ensure your circuit can handle the step-up voltages generated between the higher inductance taps when power is supplied between the lower inductance taps.
 

ronsimpson

Joined Oct 7, 2019
1,227
You can wind 1-2, 3-4 or you can wind 1-2-4 and not cut the wire.

50A so you are using large wire. Are you going to use Litz wire.

From Coilcraft:
1607127224266.png1607127329988.png
 

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Thread Starter

Manjesh Gowda

Joined Oct 19, 2020
83
Just be aware you are going to get transformer action on your other taps in any configuration you use. Think of it like an autotransformer or an isolation transformer. You'll need to ensure your circuit can handle the step-up voltages generated between the higher inductance taps when power is supplied between the lower inductance taps.
Thank you for the response... I think I am not going to get transformer action when I connect between 1 and 2, 3and 4, 1 and 4, I only use any one of these combination for ex; if i use 1 and 2 which gives me 14uH then I am gonna leave 3 and 4 open ends.. correct me if i am wrong.. Thank you
 

ronsimpson

Joined Oct 7, 2019
1,227
I am not going to get transformer action when .....
When you apply voltage 1-2 you will get voltage 3-4 just like a transformer. Even when you do not connect 3-4.
Not cut the wire.... Could you please brief me..
Option 1) Wrap wire on pin1. Wind 3 turns. Wrap wire on pin2, cut wire. Wrap wire on pin3. Wind 5 turns. Wrap wire on pin 4, cut wire.
Option 2) Wrap wire on pin1. Wind 3 turns. Wrap wire on pin 2. (do not cut but go back into the transformer) Wind 5 turns. Wrap wire on pin4, cut wire.
Option 3) ......... Wrap wire on pin2 & 3 then back into transformer. ..........
 

Wolframore

Joined Jan 21, 2019
2,273
is this similar to what you want to do? It would appear you need to short out the area you do not want to do otherwise it might become an antenna

56A97887-51C0-4BFC-88E5-E3504257B058.jpeg
 

Thread Starter

Manjesh Gowda

Joined Oct 19, 2020
83
When you apply voltage 1-2 you will get voltage 3-4 just like a transformer. Even when you do not connect 3-4.

Option 1) Wrap wire on pin1. Wind 3 turns. Wrap wire on pin2, cut wire. Wrap wire on pin3. Wind 5 turns. Wrap wire on pin 4, cut wire.
Option 2) Wrap wire on pin1. Wind 3 turns. Wrap wire on pin 2. (do not cut but go back into the transformer) Wind 5 turns. Wrap wire on pin4, cut wire.
Option 3) ......... Wrap wire on pin2 & 3 then back into transformer. ..........
I am thinking of doing option 1...Just to make it simple.. I want to get 3 inductance value from a single inductor. As u said in option 1 i could get 3 values
1) Connectin pin 1 and 2
2) Connecting 3 and 4 leads to one inductance value
3) connect jumper between 2 and 3 which make the inductance series. Here i will get another value..
But I only use 1 combination from one inductor at a time..
Please let me know if my approach is right
 
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