Materials used for manufacturing of toroid cores, wound cores and unicore cores operating at frequency of 50 Hz
The selection of optimal thickness of an GO band is based on the fact that smaller is the thickness lower are the hysteresis losses. On the other hand specific losses caused by eddy current decrease of the sheet thickness by a quadrate. The total of both losses results in significant minimum of total specific losses for range of band thickness from 0.23 to 0.35 mm and 50 Hz frequency.
Wound cores of magnetic circuits produced by Liberty Technotron s.r.o. Company are manufactured form grain oriented transformer metal band with oriented structure. Thanks to this oriented structure these materials provide high magnetic orientation and are divided to several qualities, as you can see in the table below.
( mm )
|Quality||Max. specific losses ( W/kg )||Min. magnetic induction ( T )|
|EN 10107||DIN 46400||AISI||P1,5/50Hz||P1,7/50Hz||B800|
|0,23||M127 – 23S||23M3||0,8||1,27||1,75|
|0,27||M140 – 27S||VM 89 – 27N||27M4||0,89||1,40||1,75|
|0,30||M150 – 30S||VM 97 – 30N||30M5||0,97||1,50||1,75|
|0,35||M165 – 35S||VM 111 – 35N||35M6||1,11||1,65||1,75|
|0,23||M110 – 23S||0,73||1,1||1,78|
|0,23||M120 – 23S||0,77||1,20||1,78|
|0,27||M130 – 27S||VM 130 – 27S||0,85||1,30||1,78|
|0,30||M140 – 30S||VM 140 – 30S||0,92||1,40||1,78|
|0,35||M150 – 35S||VM 155 – 35S||1,05||1,50||1,78|
|0,23||M 100 – 23P||1,00||1,85|
|0,27||M 103 – 27P||27MOH||1,03||1,88|
|0,30||M 105 – 30P||30MOH||1,05||1,88|
|0,30||M 111 – 30P||VM 111 – 30P||30M1H||1,11||1,88|
|0,30||M 117 – 30P||VM 117 – 30P||30M2H||1,17||1,85|
FREQUENCIES OF 400 – 1000 HZ
To be able minimize weight and volume of magnetic circuits we need to increase frequency of supply voltage. When the supply voltage frequency increases we are able to decrease the magnetic circuit cross-section and consequently its weight and volume. Upon customer request we manufacture wound magnetic circuits from Fe – 3% Si band, nominal thickness 0.15 mm.
Elementary material properties as follows:
|Nominal thickness( mm )||Magnetizing frequency [Hz]||Nominal losses [W/kg]||Magnetic polarization J [T] at the magnetic field intensity H [A/m]||Initial permeability at magnetic field intensity|
The band used is ceramic insulated on both sides with the heat resistance up to 900 °C. Corresponding specific losses at frequency of 400 Hz/1T are 8 – 8.5 W/kg.
Magnetic wound circuits made of 0.15 mm material are cost-effective for electrical machinery producers even though the fact that when compared with the C/0.30 mm cores their price is about 100 % higher.