Induction header - Magnetic Field Concentration
nxplace, Fri Feb 03 2017, 07:20PMHi,
I made a ZVS Induction Heater. How can i have a medium power (like 500w) but with a tiny induction coil. The small piece I want heat have 5mm x 2 mm, How can i concentrate all the induction inside this space?
If i put a small coil, the frequency will be too high. May i user a coil like this:
Induction coil
Any ideal?
Re: Induction header - Magnetic Field Concentration
klugesmith, Fri Feb 03 2017, 07:32PM
Welcome to the 4hv.org forum.
>> If i put a small coil, the frequency will be too high.
That could be mitigated by putting more turns on the small work coil.
It doesn't need to be single-layer.
It doesn't need to be made from tubing, with coolant flow inside the conductor.
You can also bring the frequency down by increasing the tank capacitance. Then tank impedance will be lower, and current higher. Might require different coupling to your ZVS driver.
klugesmith, Fri Feb 03 2017, 07:32PM
Welcome to the 4hv.org forum.
>> If i put a small coil, the frequency will be too high.
That could be mitigated by putting more turns on the small work coil.
It doesn't need to be single-layer.
It doesn't need to be made from tubing, with coolant flow inside the conductor.
You can also bring the frequency down by increasing the tank capacitance. Then tank impedance will be lower, and current higher. Might require different coupling to your ZVS driver.
Re: Induction header - Magnetic Field Concentration
nxplace, Fri Feb 03 2017, 08:19PM
Thank you klugesmith.
If i do many turns, the second layer will not receive the induction of the first layer, and the third layer will no receive the induction of layer 1 and 2...?
nxplace, Fri Feb 03 2017, 08:19PM
Thank you klugesmith.
If i do many turns, the second layer will not receive the induction of the first layer, and the third layer will no receive the induction of layer 1 and 2...?
Re: Induction header - Magnetic Field Concentration
klugesmith, Sat Feb 04 2017, 12:28AM
No.
To find the magnetic flux density in the middle, you simply add the flux density due to each layer.
The flux due to each layer also, more or less, threads all the other layers. So total inductance, assuming the layers are connected together in series, still tends to go up with the square of the total turns count. Are you familiar with air-core coil formulas and online calculators?
Here's a 25-tesla resistive electromagnet with 5 layers of Florida Bitter solenoid windings and 27 or 28 megawatts of DC power.
The same lab recently commissioned a 45-tesla hybrid electromagnet. A 33.5 tesla resistive magnet (apparently with three layers) is surrounded by an 11.5-tesla superconducting magnet.
klugesmith, Sat Feb 04 2017, 12:28AM
No.
To find the magnetic flux density in the middle, you simply add the flux density due to each layer.
The flux due to each layer also, more or less, threads all the other layers. So total inductance, assuming the layers are connected together in series, still tends to go up with the square of the total turns count. Are you familiar with air-core coil formulas and online calculators?
Here's a 25-tesla resistive electromagnet with 5 layers of Florida Bitter solenoid windings and 27 or 28 megawatts of DC power.
The same lab recently commissioned a 45-tesla hybrid electromagnet. A 33.5 tesla resistive magnet (apparently with three layers) is surrounded by an 11.5-tesla superconducting magnet.
Re: Induction header - Magnetic Field Concentration
jpsmith123, Sat Feb 04 2017, 03:19AM
Can you just use a piece of ferrite to concentrate the field?
jpsmith123, Sat Feb 04 2017, 03:19AM
Can you just use a piece of ferrite to concentrate the field?
Re: Induction header - Magnetic Field Concentration
nxplace, Sat Feb 04 2017, 11:25PM
I tried with many turn. The concentration is good but the current graphic is weird.
I found a couple of exemple with ferrite:
demo 1
demo 2
demo 2
With method is better ferrite or multi layer? What are advantage/disadvantagee?
nxplace, Sat Feb 04 2017, 11:25PM
I tried with many turn. The concentration is good but the current graphic is weird.
I found a couple of exemple with ferrite:
demo 1
demo 2
demo 2
With method is better ferrite or multi layer? What are advantage/disadvantagee?
Re: Induction header - Magnetic Field Concentration
jpsmith123, Sun Feb 05 2017, 07:32PM
You can probably get some ferrite inexpensively on ebay, e.g., a ferrite rod, and then do an experiment to see how it works for your application.
Or you can get a big "U" core and two "I" pieces from TSC international and create something more sophisticated.
I'm wondering things like: What metal are you trying to heat, what temperature are you trying to reach, is there anything critically important about the process, and is this for mass production or just one or two pieces?
jpsmith123, Sun Feb 05 2017, 07:32PM
You can probably get some ferrite inexpensively on ebay, e.g., a ferrite rod, and then do an experiment to see how it works for your application.
Or you can get a big "U" core and two "I" pieces from TSC international and create something more sophisticated.
I'm wondering things like: What metal are you trying to heat, what temperature are you trying to reach, is there anything critically important about the process, and is this for mass production or just one or two pieces?
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