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Author Topic: Custom u cores anyone?  (Read 23507 times)

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Re: Custom u cores anyone?
« Reply #32 on: January 09, 2012, 20:02:38 pm »
Tony, What was the thickness?
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Re: Custom u cores anyone?
« Reply #33 on: January 09, 2012, 20:33:36 pm »
they are 0.125" thick, 3" x 3" square slabs....here's the part #I349-40/.125
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Re: Custom u cores anyone?
« Reply #34 on: January 10, 2012, 00:00:54 am »
All,

I've made fine iron powder and epoxy cores and they will not saturate but have a inductance too low for us I think.  It is much below 400uh and works nicely for 60hz but not much good at khz frequencies.  Same experience with steel strips from an old microwave oven transformer.  Since that experiment, I've bundled and put seven 1/4" ferrite rods through standard wire bobbins off the shelf and matched the ends with rectangular ferrite strips about five high.  It works well and is cheap from ebay.

kb
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Re: Custom u cores anyone?
« Reply #35 on: January 10, 2012, 09:15:34 am »
Quote from: Login to see usernames on January 10, 2012, 00:00:54 am
All,

I've made fine iron powder and epoxy cores and they will not saturate but have a inductance too low for us I think.  It is much below 400uh and works nicely for 60hz but not much good at khz frequencies.  Same experience with steel strips from an old microwave oven transformer.  Since that experiment, I've bundled and put seven 1/4" ferrite rods through standard wire bobbins off the shelf and matched the ends with rectangular ferrite strips about five high.  It works well and is cheap from ebay.

kb

What ferrite rods are you using?
Are they balun ferrite rods?
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Re: Custom u cores anyone?
« Reply #36 on: January 10, 2012, 23:13:46 pm »
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Re: Custom u cores anyone?
« Reply #37 on: January 10, 2012, 23:30:13 pm »
Those rods are 400perm. I think I have something pretty close to those but have not had any luck using them. What frequency range are you working with?
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Re: Custom u cores anyone?
« Reply #38 on: January 10, 2012, 23:46:44 pm »
It seems to work well across a wide frequency range.  I L meter measure at 1.2h with seven of them bundled as a core using a standard spool of 1000' 28 gauge.  My VIC has two sets of two for chokes on the five coil setup. 

Question for Tony,  Do you get the waveform by using a second diode across the negative secondary pointing to and connecting after the meyer diode?

kb
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Re: Custom u cores anyone?
« Reply #39 on: January 11, 2012, 10:01:51 am »
Hi kickbackemf
Can you post a picture of your VIC ?
I have lots of these rods around but inductance readings look too low. I wound  aprox 100 turn on one of them and resulted in only 0.6mH.


HM
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