I found these to be cheap on ebay. I need 2.0mH for my crossover maybe I can use this as is or unwind it?
Does anyone know if it will be adequate?
Maybe run a distortion test using a first order crossover and use REW to look for problems. Or do a listening test and see if you hear distortion products related to poor iron.
You should be able to take a few turns out without pulling the core apart. Should not be too many turns to remove considering inductance relies on the number of turns squared.
Also if you can guess the total number of turns you should be able to guess how many to remove.
You should be able to take a few turns out without pulling the core apart. Should not be too many turns to remove considering inductance relies on the number of turns squared.
Also if you can guess the total number of turns you should be able to guess how many to remove.
I wonder what kind of air gap (if any) it has. And if it has 2.5mH inductance AT 6 amps, 50 Hz.
Unless the gap can be seen from the bottom I am going to guess it does not have a gap. Considering it is rated in HZ rather than DC. Mostly need to run some tests to see where the core gives up. Also see if it leaves any hysteresis distortion. Core made of recycled dog food cans or special iron?
Probably the same iron as the transformer that runs the thermostat in your central AC. It has that look about it.
Unless there is some sort of gap closed iron cores give up in the milliamps, not single digit amps. Might handle 6 amps without excessive temperature rise, but a lot less at 50Hz before saturation.
Unless there is some sort of gap closed iron cores give up in the milliamps, not single digit amps. Might handle 6 amps without excessive temperature rise, but a lot less at 50Hz before saturation.
With EI cores, closed magnetic circuit, you do need air gap to linearize the inductance as well as increase saturation current.
I always use this type of core for woofer, but I mount it as an E and an I separately, not interlaced as in a regular transformer.
Then I insert a film or thick paper shim in between the E and the I, creating the air gap, in order to limit the relative magnetic permeability between 10 to 20.
In addition, do not use that kind of clamp that most transformer has. When you have an air gap, it interfers and create harmonic distortion.
A core of 20x20cm is fine for up to 10Apeak if limiting the uR mentioned above.
I always use this type of core for woofer, but I mount it as an E and an I separately, not interlaced as in a regular transformer.
Then I insert a film or thick paper shim in between the E and the I, creating the air gap, in order to limit the relative magnetic permeability between 10 to 20.
In addition, do not use that kind of clamp that most transformer has. When you have an air gap, it interfers and create harmonic distortion.
A core of 20x20cm is fine for up to 10Apeak if limiting the uR mentioned above.
For crossover coils, I usually don’t even put the I’s back. Just shove the bobbin thru the E’s. It still concentrates nearly all the flux thru the center leg, enough that it still follows the square law for tuning.
Then the I’s can be used to make another, smaller inductor.
Then the I’s can be used to make another, smaller inductor.
Sure, if you just need uR around 8 to 10 (more or less), using only the "E" gives you a very linear and robust inductor which handles a lot of current before saturation.
And still, 8 to 10, it's a lot of "gain" compared to the air core only. You can save copper and have low DCR inductor.