Core losses are frequency dependance, the higher the frequency the more eddy currents, that’s why amorphous and nanocrystalline are popular (mostly used for power supplies) because they have really thin laminations 18μm-22μm.
For SiFe, thinner laminations have less permeabilty and more constant permeability. A 0,05mm SiFe core has almost flat permeabilty (μr about 1000) up to 10kHz but also a lot lower permeabilty then 0,3mm. The 0,3mm starts from 20.000 (dependable about the quality of the core) but drops very, very fast after hundred Hz.
Btw Gorgon53 says: “ 0,5mm has usually higher losses and less permeability” .
Maybe he has right, maybe not. The dc permeability of 0,5mm is higher then 0,3mm but at 50/60Hz there could be so much eddy currents already that permeability is already lower at that those frequencies.
For SiFe, thinner laminations have less permeabilty and more constant permeability. A 0,05mm SiFe core has almost flat permeabilty (μr about 1000) up to 10kHz but also a lot lower permeabilty then 0,3mm. The 0,3mm starts from 20.000 (dependable about the quality of the core) but drops very, very fast after hundred Hz.
Btw Gorgon53 says: “ 0,5mm has usually higher losses and less permeability” .
Maybe he has right, maybe not. The dc permeability of 0,5mm is higher then 0,3mm but at 50/60Hz there could be so much eddy currents already that permeability is already lower at that those frequencies.
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FWIW-
ChiFi unit 350 watt (114 wide x 65 thick mm) I'm rewinding shown in previous post pics, has laminates of .015", They are soft...
US made 630 watt (114 wide x 82 thick mm) laminates are .025"... They are noticeably more rigid- more than just the increase in thickness- imo...
Remarkably similar to a lathe..
Do you have a tension spec- Ft/lbs or N/M you observe while winding?
Also, does that figure vary as distance from the core?
Jim
Some random pictures of my winding setup. A manual rotation and semi feeding mechanicsm.. The feeder works pretty good, Not as accurate as servo motor microprocessor controlled,but very durable and with patient winding,does the job nice
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Well done! Clean design!
Sharing some kinky stuff from 2017, where I started learning and experimenting with too many things at once. Photo 4 is a vertically sectioned interstage transformer. Photos 1,2 and 3 represent heater transformer windings with many voltages. Photos 5 and 6 are depicting a power supply transformer for tube amplifier, with HT and heater voltages.
Sharing some kinky stuff from 2017, where I started learning and experimenting with too many things at once. Photo 4 is a vertically sectioned interstage transformer. Photos 1,2 and 3 represent heater transformer windings with many voltages. Photos 5 and 6 are depicting a power supply transformer for tube amplifier, with HT and heater voltages.
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tnvijay, pl post more details of the output transformers you wound...assume those were for the baby Huey el84 amp.
core size, winding details...
What Bdc has to do with L ?
Think about it, Simple example:
You have your power trasformer, you connect your primery to 120VDC instead of 120VAC, what happens to your transformer, though the L and T is still the same?
Bdc is proportional to AmpTurns, concidering the core is still the same, so the lager current and/or the more turns, the higher Bdc. L is for calculation of Bac at specified frequency.
Any comments?
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Don't get me wrong, Bac also depends of AmpsTurns, but with the AC, the current will be different, thats where L comes to its role. In this care the current depends on the combined impedance of the inductor, including R and X (I am not getting into the vector agebra). R is a pure DC resistance, X=2*3,14*f*L.
R in Ohms, f in Hz, L in Henry. X is in Ohms.
R in Ohms, f in Hz, L in Henry. X is in Ohms.