| FT-3AM
bead cores made of FT-3AM nanocrystalline
material are cores for surge absorbers
which have high pulse permeability.
These cores have excellent performance
in suppression of reverse recovery current
from the diode and ringing or surge
current from switching circuit.
Comparison of FT-3AM nanocrystalline
material to other materials:
|
Major
Applications
-
Suppression of reverse recovery
current and surge current from
the diode in switch mode power
supplies or inverters
-
Suppression of the surge current
at the moment of activation of
current in the diode, such as
power MOS-FET.
-
Suppression of spike or ringing
current generated in the switching
circuit.
|
|
-
The
saturation magnetic flux density
is twice as high as that of
Co-based amorphous metal and
three times higher than that
of Ni-Zn ferrite. The pulse
permeability and the core loss
are comparable to Co-based amorphous
metal. As a result, a small
core made of FT-3AM nanocrystalline
material offers higher performance
in suppression of surge current
and voltage.
-
The temperature characteristics
of FT-3AM nanocrystalline material
are very stable due to its high
curie temperature, 570ºC,
and is much superior to Co-based
amorphous metal and Ni-Zn
ferrite which have curie temperatures
around 200ºC.
-
FT-3AM nanocrystalline material
cores have a lower cost than
comparable Co-based amorphous
metal cores.
|
|
|
Comparison
of magnetic and Physical Properties
among FT3-AM, FT-3AH,
and conventional materials
|
|
|
FT-3AM
|
FT-3AH
|
Co-based
amorphous
|
Ni-Zn
ferrite
|
|
Saturation
flux density Bs *(T)
|
20º
C
|
1.23
|
1.23
|
0.60
|
0.38
|
|
100º
C
|
1.20
|
1.20
|
0.53
|
0.29
|
|
Squareness
ratio Br /
Bs
|
20º
C
|
0.50
|
0.90
|
0.80
|
0.71
|
|
100º
C
|
0.48
|
0.91
|
0.78
|
0.60
|
|
Coercive
force Hc*(A/m)
|
20º
C
|
2.5
|
0.62
|
0.30
|
30
|
|
100º
C
|
2.7
|
0.63
|
0.29
|
20
|
|
Pulse
permeability µ rp**
|
3500
|
4000
|
4500
|
500
|
|
Core
loss Pcv**(J/m3)
|
7.5
|
6.5
|
6.0
|
7.0
|
|
Curie
temperature Tc(ºC)
|
570
|
570
|
210
|
200
|
|
Saturation
magnetostriction as(x10-6)
|
~
0
|
~0
|
~0
|
-7.8
|
Electrical
resistivity p(µ
· m)
|
1.2
|
1.2
|
1.3
|
1X1012
|
|
Density
d(kg/m3)
|
7.3X103
|
7.3X103
|
7.6X103
|
5.2X103
|
|
* DC magnetic properties
at 800 A/m
** Pulse width 0.1µs
, operating magnetic flux density  B=0.2T
|
