DIY Transformer, number of turns of the primary winding

[oldway]

There seems to be something very wrong with your transformer. 

To compare, I have a medical grade toroidal tranformer of 1KVA and the magetization current is 60mA at 234V

To reduce magnetization current, you must increase the number of turns to reduce induction.

But number of turns is correct, it should not give such a high current....

In my opinion, there is something wrong with the core: laminates are not isolated each from another and there is a high Eddy current induced in the core. The curve seems to proove that this is the problem.

Core seems to saturate with 0.6T (6000 Gauss), that's not possible, even low quality magnetic laminates (low carbon steel) saturate above 1T (10.000 Gauss).

Where is this core coming from ? Perhaps from a defective transformer ?

[Phil Smith]

That's exactly what I thought then I'd winded the primary for the first time.. The core is a garbage.
Unfortunately the its history is a mystery for me, cause the guy, who sold it to me, said just it was used in some rectifiers. That's it. 
So, the chapter is closed and there's no need to spent more time on this piece of crap?

[oldway]

Don't you see something wrong with this core ? Perhaps somebody has welded the laminates to secure them together ? This can't be done, laminates must be isolated to lower Eddy current.

[Phil Smith]

No, it wasn't welded together. If I remember correctly, the last turn of the lamination was taped to prevent unwrapping. But I guess, from visual observation, the iron strip was just spiral winded without any isolation between turns whatsoever

[Phil Smith]

Ok, probably this core was used in a some form of inductor instead of a transformer..
I've got one protect, which needs several induction coils. It's a 8 speaker emulator for 100w guitar amp. There are 3 similar channel - left wet, right wen and dry. Each channel contains 3 coils (See Fig.01 Just one channel shown, all three channels are identical)
The original article is here - http://www.aikenamps.com/index.php/designing-a-reactive-speaker-load-emulator

A Question is - can them all be winded on the same core (See Fig.02)? If yes, it would be great!

[oldway]

This magnetic core is very bad, it saturates with an induction of about 0.6T (6.000 Gauss), it can not serve anything except to be sent to recycling. With crap core, you will only make a crap inductor...

As for the inductances for crossover, it must be linear to avoid distorting the sound.

It is therefore necessary to use either inductances without core, or with a good quality core with a large air gap to linearize its inductance curve.

It is not possible to use this magnetic core because:
1) the steel used has very poor ferro-magnetic properties. Even working with a low induction, hysteresis losses and Eddy current will be far too high at higher frequencies....
2) It is very difficult to create an air gap, it will be necessary to saw the core. Even so, the gap will be probably too little.

Inductance of crossover must be of very high quality, no way to use a crap core who does not even serve to make a 50Hz transformer.....

[Phil Smith]

Thank you very much, oldway!
To the bin it will go straight away
There was an idea to put two 1.2kW microwave xformers back-to-back (230 V -> 2200 V -> 2200V -> 230V), but I've read this setup has more cons than pros..

[oldway]

....
There was an idea to put two 1.2kW microwave xformers back-to-back (230 V -> 2200 V -> 2200V -> 230V), but I've read this setup has more cons than pros..

There is a certainty: if you are smart, you will never do this because:

1) the MOT's are true killers .... never use them with their high voltage secondary.

2) they have a high short circuit impedance (about 20%), using two of them in serie give a short circuit impedance of 40% ... That's mean that output voltage will drop heavily whith current, so it is fully useless .. ..A big dangerous crap bullshit ....

Stupid people are posting madness on internet.....

[Phil Smith]

....
There was an idea to put two 1.2kW microwave xformers back-to-back (230 V -> 2200 V -> 2200V -> 230V), but I've read this setup has more cons than pros..

There is a certainty: if you are smart, you will never do this because:

1) the MOT's are true killers .... never use them with their high voltage secondary.

2) they have a high short circuit impedance (about 20%), using two of them in serie give a short circuit impedance of 40% ... That's mean that output voltage will drop heavily whith current, so it is fully useless .. ..A big dangerous crap bullshit ....

Stupid people are posting madness on internet.....

100% agree with you