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Audio Description – Course 3, Transformer Core Material
– Clip 1 Introduction – Clip 2 Course Description – Clip 3 Test Parameters – Clip 4 Test Equipment – Clip 5 Air core vs Iron core – Clip 6 Core symbols – Clip 7 Amorphous Metals – Clip 8 Process of making Metglas – Clip 9 Overview – Clip 10 Air core explained – Clip 11 Air core at 5 KHz, sine wave – Clip 12 Air core at resonance frequency, sine wave – Clip 13 Air core at square wave – Clip 14 Nanoperm at 5 Khz – Clip 15 Nanoperm at high frequency, sine and square wave – Clip 16 Ferrite at sine wave – Clip 17 Ferrite sine and square wave high frequency connected – Clip 18 Metglas at 5 Khz, sine wave – Clip 19 Metglas high frequency sine and square wave – Clip 20 Metglas at pulse frequency – Clip 21 First Summary – Clip 22 End Course 3
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Clip 1
In this course I will investigate the properties of core materials on transformers. I use sine and square waves and voltage of 5 Volt to analyse the feedback of the coil. All coils except the air core have a ration of primary to secondary of 1:2. This rule does not apply for air cores because we have here transmission line phenomena. The lumped circuit rule does not apply here. In transformer below resonant frequency the ratio of coil winding’s is dominant.
Clip 2
Clip2
Course Description
Waveform propagation in core materials
of a transformer– Select sine and square wave and analyze the feedback curve from the transformer
– Analyze the characteristic of different core materials
– Identify the core material suited for the specific application
– Compare the efficiency of core materials from a current draw point of view
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Clip 3
Test Parameters
1. One Amplifier Module with 2N3055 Transistor
2. Tesla coil
3. Nanoperm core
4. Ferrite core
5. Amorphous metal core (metallic glass)
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Clip 4
Test Equipment
Tools– EA, PS 2000 B, 84 V 5 A, Power supply
– Agilent/Keysight InfiniVision 3000 Series oscilloscope DSOX3014A
– External 19 Inch Monitor for Oscilloscope
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Clip 5
Air core versus Iron core
The gain is concentrated magnetic field lines but with the sacrifices of reduced
frequency response. Mostly not reaching resonant frequency of the co
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Clip 6
Coil with core symbols
Good to see that the iron core versus the ferrite core has a solid line drawn . It represents a stronger magnetic flux concentration. The ferrite core however is capable to operate at higher frequencies, able to work with the resonance frequency of the coil.
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Clip 7
Amorphous Metals. Metglas is trademark of Metglas, which has been bought by Hitachi. The products are not available of the shelve and need to manufactured as prototype for an outlined application. The quote I received for the same dimensions of the amorphous core I use is around 450$ for a production of 10. The core I used is from a competitor in China with products off the shelve for a fraction of this price.
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Clip 8
The process of creating Metallic glass
The key is to cool down so fast that the atoms cannot form a crystal structure. The atoms are so
uniform packed that the special property as core material is created. Amorphous because they
are still in motion like glass
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Summary
There is no clear winner as such for the perfect core material. It depends entirely on the
application required. For full flexibility in frequency only an Air core can do that. Downside
is that the radiation is great losing energy with low coupling or K factor. Very high sensitivity
to stray capacitance and magnetic fields. Soft Iron core are very strong and the material of
choice if it comes down to high power Transformer requirements at mains frequency.
Downside here is low frequency response, not higher than 1 KHz, suspect to eddy current.
Only laminated cores are good. Good cores can reach 92-95% efficiency or high power factor.
Ferrite cores vary from material to material with the strongest as Nanoperm. Here is also a low
frequency response. No radiation and with softer ferrite is a resonance coil construction
possible. Metallic glass or amorphous metal is an exotic material. Used were losses are kept to
an absolute minimum. It does compensate for the price tag in savings of energy. From a application
point of view most high power pulse system like Laser, Radar, MRI is only possible with such
core materials. One application I like to add is to use it as transformer for a Tesla Coil and
High Voltage static electricity like from a Wimshurst machine.
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Clip 22
The End Course 3
Transformer Core Material