2,808
edits
Changes
→Silver–Molybdenum (SILMODUR) Materials
Fig. 2.137: Micro structure of Ag/Mo 35/65
[[File:Micro structure of Ag Mo 35 65.jpg|right|thumb|Micro structure of Ag/Mo 35/65]]
'''Table 2.36: Physical Properties of Contact Materials Based on Silver–Tungsten (SIWODUR),
[[File:Physical Properties of-Contact Materials Based.jpg|right|thumb|Physical Properties of Contact Materials Based on Silver–Tungsten (SIWODUR), Silver–Tungsten Carbide (SIWODUR C) and Silver Molybdenum (SILMODUR)]]
'''Table 2.37: Contact and Switching Properties of Contact Materials Based on Silver – Tungsten
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s12">Material/ DODUCO- Designation</p></td><td><p class="s12">Properties</p></td></tr><tr><td><p class="s12">Silver-Tungsten</p><p class="s12">SIWODUR</p><p class="s12">Silver-tungsten carbide SIWODUR C</p></td><td><p class="s12">Tendency to weld at high make currents in symmetrical pairing,</p><p class="s12">Higher contact resistance and higher temperature rise over increased number of operations through tungsten oxide and tungstate formation, especially for Ag/W,</p><p class="s12">High welding tendency of closed contacts during short circuit,</p><p class="s12">Very high arc erosion resistance, poor arc moving properties, High hardness and low formability,</p><p class="s12">Easy to braze and weld through Ag enriched backing layer</p></td></tr><tr><td><p class="s12">Silver-Tungsten Carbide plus Grafit SIWODUR C Plus</p></td><td><p class="s12">Low contact resistance and low temperature rise through graphite addition,</p><p class="s12">Lower tendency to contact welding, Lower arc erosion resistance than Ag/W</p></td></tr><tr><td><p class="s12">Silver-Molybdenum</p><p class="s12">SILMODUR</p></td><td><p class="s12">Better contact resistance stability due to less stable surface layers,</p><p class="s12">Lower arc erosion resistance than Ag/W</p></td></tr></table>
'''Table 2.38: Application Examples and Forms of Supply for Contact Materials Based
on Silver–Tungsten (SIWODUR), Silver–Tungsten Carbide (SIWODUR C) and Silver Molybdenum (SILMODUR)'''
{| class="twocolortable" style="text-align: left; font-size: 12px"
|-
!Material
!Application Examples
!Form of Supply
|-
|Ag/W<br />SIWODUR
|Circuit breakers (not current limiting)
||rowspan="3" | Contact tips, brazed and welded<br />contact parts
|-
|Ag/W<br />SIWODUR<br />Ag/WC<br />SIWODUR C<br />Ag/WC/C<br />SIWODUR C/C
|(Main) Power switches<br /> paired with Ag/C)<br />
Fault current circuit breakers<br />(paired with Ag/C)
|-
|Ag/Mo<br />SILMODUR
|Device protection switches
|}
=== Copper–Tungsten (CUWODUR) Materials===