Toroidal Cut Core

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Toroidal Cut Core

Description

Permanent Magnets Ltd. (PML) supplies Cut cores in soft magnetic Nickel alloy material to industries requiring High accuracy flux Concentrator used in current sensing application. Depending on the application, customers can select suitable Nickel or Silicon Iron alloy. PML maintains close control of magnetic properties by properly heat treating in a controlled hydrogen atmosphere furnace, which permits the most economical and efficient design for transformers. PML manufactures Cut cores in Toroid and Rectangular shape. The cut cores are made robust by finishing them with varnish coating.

We supply cut cores in a comprehensive range of sizes. Standard strip thickness used for cut cores are 0.1mm and 0.2mm.

Application of Toroidal Cut Core

Material Properties

Magnetic & Chemical Properties
Properties Measurement Unit 80% NiFe7
Permeability Permeability AC
Bs Tesla 0.751
Br Tesla 0.42
Hc 2(A.m)-1 Tesla 0.35
µ4 4 Tesla 550000
µ max Tesla 570000
Permeability AC
µ4z5 70000
µz86 -
µmax 95000
Core loss (W/Kg-1) 0.015
Chemical Composition % Ni - 78%-81%
% Mo - 4.5%-6%
% Si - 0.05%-0.4%
% Mn - 0%-0.5%
% C - 0.01%
% Fe - Balance
Physical
Properties 		Density (g.cm -3) 8.7
Specific Heat (J.Kg-1.˚C-1) 460
Thermal conductivity W.m-1.˚C-1 19
Mean CTE between -50 & +200˚C ˚C-1 12.10-6
Electrical resistivity µΩ.cm 60
Curie Point ᵒC 420
Coefficient of magnetostriction at Saturation ∆l / l - 1-3 x 10-6
Melting temperature ᵒC 1450
Saturation Induction Tesla -
Hardness Hv 325
In Cold worked
condition 		UTS MPa 1050
0.2% PS(Cold Worked) MPa 1030
Elongation % min 3
In Annealed
condition 		Hardness Hv 160
UTS MPa 650
0.2% PS MPa 280
Elongation % 35
Grain Size - 8

Key:

  1. Practical saturation measured for H = 800 A/m.
  2. Remanent induction Br and coercive field Hc measured from H = 80 A/m.
  3. Practical saturation Bs and Remanent induction Br measured for H = 800 A/m.
  4. Measured for H = 4 mA/cm (peak value).
  5. Sinusoidal excitation field H = 4 mA/cm (peak value).
  6. Impedance permeability for B = 0.8 T.
  7. Measurements made on 35X26X0.34 mm ring specimens after annealing in Pure
    & Dry Hydrogen for 4h at 1170°C followed by cooling at 200°C/h.
  8. Practical saturation measured for H=5000A/m.
  9. Core loss W/kg at 1.5T at 50Hz=3.90 max.
  10. Typical operating frequency - 50 hz to 400hz

Dimensions and tolerances:

DIMENSIONS AND TOLERANCE
Outer Diameter (mm) Tolerance (mm) Inner Diameter (mm) Tolerance (mm) Height Tolerance (mm)
< 10 ± 0.4 < 10 ± 0.3 ± 0.3
< 25 ± 0.5 < 25 ± 0.4 ± 0.4
< 50 ± 1.0 < 50 ± 0.5 ± 0.5
< 80 ± 1.25 < 80 ± 0.75 ± 0.8
< 100 ± 1.5 < 100 ± 0.8 ± 0.8
< 160 ± 2.0 < 160 ± 1.3 ± 1.5
< 200 ± 2.5 < 200 ± 1.5 ± 1.5
< 320 ± 2.5 < 320 ± 2.0 ± 2.0
NOTE: General Cutting gap tolerance will be ± 0.5mm

Applications

Current measurement for:
  • Automotive
  • Aerospace
  • Medical
  • Renewable energy

Testing

As a standard practice PML checks Toroidal core (before cutting) for magnetic properties by tracing the B-H properties of the core itself. Below are results of a sample core

Sample Core Geometry
  • Outer Diameter - 160 mm+/-2mm
  • Inner Diameter - 110 mm+/-1mm
  • Height - 30 mm+0.2 /- 0.0 mm

Application Toroidal core Hysteresis Loop Diagram

Ind Pk(T) Permeability Loss/kg (Wt) H EffPk (A/cm) H RMS (A/cm) Ind RMS (T) Hc (A/cm) Br (T)
0.1 127150.24 0 0.0083 0.0059 0.0672 0.0019 0.02
0.2 144038.48 0 0.0134 0.0095 0.1378 0.0073 0.0868
0.3 158385.11 0 0.0188 0.0133 0.2102 0.0125 0.1708
0.4 164657.89 0 0.0242 0.0171 0.277 0.0166 0.2839
0.5 115868.36 0.0061 0.1674 0.1183 0.352 0.0204 0.3449
0.6 41492.51 0.015 0.3746 0.2649 0.4307 0.024 0.3815
0.636 14717.2 0.0183 0.4492 0.3176 0.4591 0.0253 0.3947
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