Application areas: Measuring-level current transformer used in power system, transformer used on precision measuring instruments (such as watt-hour meter). According to the requirements of different measurement accuracy of the transformer, different soft magnetic materials can be chosen as iron core materials. The higher the permeability of the iron core is, the smaller the measurement error of the transformer is, hence the accuracy is higher. At present, the most common iron core material is cold-rolled silicon steel sheet, followed by Permalloy and nano-crystalline glass alloy. In recent years, demands for transformers with high-precision level (such as class 0.2, class 0.2Sand class0.5S) increased rapidly. When small ratio, low ampere turns are required or the iron core is restricted because of the small volume, the cold-rolled silicon steel often fails to meet the accuracy requirements. Although the Permalloy iron cores with high permeability can meet the required precision, its price is very high. However use of nano-crystalline alloy iron cores can both meet the accuracy requirements and be produced at lower cost than the Permalloy. Therefore, the demand of measuring level current transformer iron core made of nano-crystalline alloy rapidly increased domestically. The typical parameters comparison of the common soft magnetic materials used for current transformer iron cores: Basic parameters Nano-crystalline iron core Permalloy (1J85) iron core Silicon steel iron core Saturation magnetic flux density (Bs) 1.25T 0.75T 2.03T Initial permeability (¦Ì0) 8¡«12, 104 5¡«8, 104 103 Maximum permeability (¦Ìm) 60, 104 60, 104 4, 104 Curie Temperature (¡æ) 570 400 740 Density (g/cm3) 7.25 8.75 7.65 Lamination factor 0.7 0.9 0.95 Thickness (mm) 0.03 0.15 0.3 Features: It is made of the iron-based nano-crystalline strips with a moderate saturation magnetic induction, high permeability and low loss, which can effectively reduce ratio difference angle difference of the transformer. The saturation magnetic induction Bs of nano-crystalline alloy is between the silicon steel and Permalloy. The lower the Bs value is, the lower the security coefficient of the instrument is. When the system failure occurs and large current through the current transformer results therefore, the iron core is more easily filled, and the secondary current no longer increases in proportion, as can assure that the secondary instruments are well protected and not to be damaged. Permeability of nano-crystalline alloy is close to Permalloy and a magnitude higher than silicon steel, so it is suitable to be made as high-precision transformer iron core. The density and lamination coefficient of nano-crystalline is lower than that of Permalloy, under the condition of the same size and similar performance of the two. In this case the nano-crystalline iron core is 1/4 lighter in weight, and 1/3 lower in the manufacturing cost. In addition, the linear range of nano-crystalline alloy is wider than that of Permalloy .It can work for a long time at temperature of -55 ~ 130 ¡æ ,with a good temperature stability. Specifications a. Rectangular core: (mm) Iron Core Size(mm) (mm) The case size(mm) Weight of the iron Core (kg per piece) Turns Ratio N1: N2 Excitation current(mA) Excitation voltage(mV) 55*97/77*119, 25 50*92/82*114, 30 0.53 1:1 25 0.45 95 2.2 1500 53 70*90/100*120, 30 65*85/105*125, 36 0.81 1:1 200 15 1:1 500 50 75*95/105*125, 25 70*90/110*130, 30 0.7 1:1 70 2 1:1 175 8 80*95/120*135, 25 75*90/125*140, 30 1.09 1:1 80 1.7 1:1 600 41 90*90/160*160, 30 85*85/165*165, 36 2.4 1:1 100 6 1:1 500 100 1:1 1000 140 135*135/260*260, 10 130*130/265*265, 16 2.3 1:1 100 1.5 1:1 500 32 82*602/138*658, 45 75*595/145*665, 55 8.8 1:1 100 1.2 1:1 1000 45 1:1 2000 120 b. Ring core: No. The iron Core Size Case size(mm) The weight of the iron core (kg per piece) Turns ratio N1: N2 is 1:1; Input current (mA), 50Hz; Output voltage (mV) 1 1105/1165, 15 1095/1175, 25 8.35 Excitation current 450 1200 2000 Excitation voltage 0.59 2.36 5.28 2 415/520, 15 409/526, 23 6.08 Excitation current 50 250 700 Excitation voltage 0.4 3 11 3 305/490, 15 299/496, 23 9.1 Excitation current 350 900 ¡¡ Excitation voltage 5 20 ¡¡ 4 315/395, 35 309/401, 43 8.2 Excitation current 120 400 ¡¡ Excitation voltage 3 11 ¡¡ 5 198/248, 30 192/254, 37 2.76 Excitation current 100 200 500 1000 Excitation voltage 2 6 35 90 6 198/248, 20 192/254, 27 1.84 Excitation current 100 200 500 1000 Excitation voltage 1.5 3.5 25 60 7 155/200, 30 150/205, 36 2 Excitation current 100 190 1000 Excitation voltage 2.5 9.5 80 8 140/180, 30 135/185, 36 1.58 Excitation current 40 80 240 Excitation voltage 1 2.9 15 9 130/190, 30 125/195, 36 2.38 Excitation current 40 80 240 Excitation voltage 1.2 3.8 17 10 100/140, 30 95/145, 36 1.19 Excitation current 30 120 500 Excitation voltage 0.85 6.8 68 11 90/130, 30 85/135, 36 1.09 Excitation current 30 120 500 Excitation voltage 0.7 6 55 12 90/125, 25 85/130, 31 0.78 Excitation current 30 120 500 Excitation voltage 0.9 7 70 13 80/120, 30 75/125, 36 0.99 Excitation current 200 500 ¡¡ Excitation voltage 20 65 ¡¡ 14 85/115, 30 80/120, 36 0.74 Excitation current 30 120 500 Excitation voltage 0.7 6.5 55 15 85/125, 20 80/130, 26 0.7 Excitation current 30 120 500 Excitation voltage 0.62 5.5 50. wooden case+carton box.
