Human Safety Relay

Product Description

Relay Components-Diagram

What is Relay?

A relay is an Electro-Mechanical switch that changes a low release current into mechanical movement. A polarized relay consists of a soft-magnetic circuit formed by an Armature and a Yoke as shown in above fig.

Relay components for human safety

These parts are made in 80% NiFe or 48% NiFe material. These parts require very high permeability and the contact area needs to have very high surface finish, flatness and cleanliness. These parts are

used in Earth Circuit Leakage Breakers (ELCB) or Residual Current Devices (RCDs) for Human Safety.

Magnetic & Chemical Properties
Permeability Properties 80% NiFe(7) 48% NiFe(8)
Permeability DC
Bs (Tesla) 0.75(1) 1.5(3)
Br (Tesla) 0.4(2) 1.1(3)
Hc(2)(A.m-1) 0.35 2.8
μ4(4) 550000 -
μmax 570000 190000
Permeability AC
μ4z(5) 70000 10400
μz8(6) - 54000
μmax 95000 -
Core Loss (W.Kg-1) 0.015 0.4
Chemical
Composition
% Ni 78%-81% 47%-48%
% Mo 4.5%-6% Nil
% Si 0.05%-0.4% 0.1
% Mn 0% -0.5% 0.50%
% C 0.01% 0.005%
% Fe Balance Balance

Note:

  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. Measurement made on 35*26*0.34mm ring specimens after annealing in Pure & Dry Hydrogen for 4h at 1170°C followed by cooling at 200°C/h
  8. Measurement made on 36*25*0.34mm ring specimens after annealing in Pure & Dry Hydrogen for 4h at 1150°C

PML provides these components with high surface finish and excellent magnetic properties as follows:

  • Surface Finish:
    • Roughness value(Ra) = 0.02 microns max.
    • Flatness = 1 light band max.
  • Magnetic properties:
    • For 45% Ni:Fe : AC Permeability at 5 mOe = 12000
    • For 80% Ni:Fe : AC Permeability at 40 gauss = 85000
  • Cleanliness for checking:
    • Cleanliness level = Class 100

Relay components handled in such clean environment, with such high surface finish and magnetic properties ultimately serves as excellent relay.