Difference between revisions of "General Rules for Dimensioning of Contacts"

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===6.4.6 General Rules for Dimensioning of Contacts===
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===<!--6.4.6-->General Rules for Dimensioning of Contacts===
  
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*'''Recommended Minimum Contact Forces at Slightly Sliding
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'''Recommended Minimum Contact Forces at Slightly Sliding Contact Make:'''
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Contact Make:'''
 
  
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{| class="twocolortable" style="text-align: left; font-size: 12px;width:30%"
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<table class="twocolortable" style="text-align: left; font-size: 12px;width:40%">
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<tr>
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<td>Gold</td>     
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<td>0.03 N </td>
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</tr><tr>
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<td>Silver </td>
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<td>0.1 N</td>
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</tr><tr>
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<td>Tungsten  </td>
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<td>0.5 N</td>
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</tr>
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</table>
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'''Contact Force Recommendations:'''
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{| class="twocolortable" style="text-align: left; font-size: 12px;width:40%"
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|-
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|Signal relays   
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|&ge; 3 cN
 +
|-
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|AC power relays 
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|&ge; 20 cN
 +
|-
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|Automotive relays 
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|&ge; 20 cN
 +
|-
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|Motor switches (Contactors)<br />(Silver – Metal oxide contacts)
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|0.05 - 0.08 N/A
 
|-
 
|-
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|Gold     
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|Power switches 
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|0.03 N
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|0.1 - 0.2 N/A
 
|-
 
|-
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|Silver   
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|Connectors<br />(Gold coating)
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|0.1 N
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|&ge; 30 cN/contact element
 
|-
 
|-
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|Tungsten 
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|Connectors<br />(Silver coating)
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|0.5 N
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|&ge; 50 cN/contact element
 
|-
 
|-
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|Connectors<br />(Tin coating)
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|&ge; 1 N/contact element
 
|}
 
|}
  
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*'''Contact Force Recommendations:'''
 
  
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Signal relays >3 cN
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'''General Rules for Dimensioning of Contact Rivets'''
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AC power relays > 20 cN
 
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Automotive relays > 20 cN
 
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Motor switches (Contactors) 0.05 - 0.08 N/A
 
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(Silver – Metal oxide contacts)
 
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Power switches 0.1 - 0.2 N/A
 
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Connectors > 30 cN/contact element
 
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(Gold coating)
 
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Connectors > 50 cN/contact element
 
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(Silver coating)
 
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Connectors > 1 N/contact element
 
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(Tin coating)
 
  
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*'''General Rules for Dimensioning of Contact Rivets'''
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[[File:General Rules for Dimensioning of Contact Rivets.jpg|left|thumb|Figure 1: General Rules for Dimensioning of Contact Rivets]]
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bild
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{| class="twocolortable" style="text-align: left; font-size: 12px;width:100%"
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|-
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!Dimensioning
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!Solid Rivets (1)
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!Composite Rivets (2)
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|-
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|a : d     
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|1.5 : 1 bis 2.5 : 1
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|2 : 1 bis 2.5 : 1
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|-
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|a : b     
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|2.5 : 1 bis 10 : 1
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|3 : 1 bis 5 : 1
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|-
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|c : b     
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|&ge; 1 : 1
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|&ge; 1 : 1
 +
|-
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|b : s     
 +
|
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|&ge; 2 : 1
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|-
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|s<sub>min</sub>   
 +
|
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|&#8776; 0.3 mm
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|}
  
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*'''Head diameter for electrical loads'''
 
  
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For AC currents: approx. 1 – 1.5 A/mm²
 
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For 1 A min. 2 mm head diameter
 
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10 A approx. 3 – 3.5 mm head diameter
 
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20 A approx. 5 mm head diameter
 
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For DC currents: approx. 0.5 – 0.8 A/mm²
 
  
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*'''Head radius R for electrical loads'''
 
  
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for I < 1 A R 1,5 mm
 
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I = 6 A R 5 mm
 
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I = 10 A R 10 mm
 
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I = 20 A R 15 mm
 
  
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*'''Failure Probability of Single and Double (Bifurcated) Contacts''' (according to Thielecke)
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'''Failure Probability of Single and Double (Bifurcated) Contacts''' (according to Thielecke)
  
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Fig. 6.18: Failure probability of a contact as a
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{| class="twocolortable" style="text-align: left; font-size: 12px;width:100%"
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function of the voltage (according to Kirchdorfer);
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|-
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Ag/Ni10; 10 mA
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!Contact force[N]   
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!colspan="4" style="text-align:center"|'''Single contact'''
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|-
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!   
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!Ag
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!AuNi 5, Pt
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!Ag
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!AuNi 5, Pt
 +
|-
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|0.04 
 +
|
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|1 x 10<sup>-4</sup>
 +
|
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|2 x 10<sup>-8</sup>
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|-
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|0.1 
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|2 x 10<sup>-3</sup>
 +
|4 x 10<sup>-5</sup>
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|8 x 10<sup>-5</sup>
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|8 x 10<sup>-9</sup>
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|-
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|0.2
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|1 x 10<sup>-4</sup>
 +
|8 x 10<sup>-6</sup>
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|4 x 10<sup>-6</sup>
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|4 x 10<sup>-8</sup>
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|-
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|0.3
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|5.5 x 10<sup>-6</sup>
 +
|1.5 x 10<sup>-6</sup>
 +
|1.8 x 10<sup>-7</sup>
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|3.2 x 10<sup>-10</sup>
 +
|}
  
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Fig. 6.19: Failure probability of a contact as a
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function of the current (according to
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<div class="multiple-images">
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Kirchdorfer); Ag/Ni10; F = 0.45 N; U = 24 V
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<figure id="fig:Failure probability of a contact as a function of the voitage">
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[[File:Failure probability of a contact as a function of the voitage.jpg|left|thumb|Figure 2: Failure probability of a contact as a function of the voltage (according to Kirchdorfer); Ag/Ni10; 10 mA]]
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</figure>
 +
 
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<figure id="fig:Failure probability of a contact as a function of the current">
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[[File:Failure probability of a contact as a function of the current.jpg|left|thumb|Figure 3: Failure probability of a contact as a function of the current (according to Kirchdorfer); Ag/Ni10; F<sub>k</sub> = 0.45 N; U = 24 V]]
 +
</figure>
 +
</div>
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<div class="clear"></div>
  
 
==References==
 
==References==
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
 +
 +
[[de:Faustregeln_für_die_Kontaktdimensionierung]]

Latest revision as of 14:01, 26 January 2023

General Rules for Dimensioning of Contacts

Recommended Minimum Contact Forces at Slightly Sliding Contact Make:

Gold 0.03 N
Silver 0.1 N
Tungsten 0.5 N

Contact Force Recommendations:

Signal relays ≥ 3 cN
AC power relays ≥ 20 cN
Automotive relays ≥ 20 cN
Motor switches (Contactors)
(Silver – Metal oxide contacts) 		0.05 - 0.08 N/A
Power switches 0.1 - 0.2 N/A
Connectors
(Gold coating) 		≥ 30 cN/contact element
Connectors
(Silver coating) 		≥ 50 cN/contact element
Connectors
(Tin coating) 		≥ 1 N/contact element


General Rules for Dimensioning of Contact Rivets

Figure 1: General Rules for Dimensioning of Contact Rivets
Dimensioning Solid Rivets (1) Composite Rivets (2)
a : d 1.5 : 1 bis 2.5 : 1 2 : 1 bis 2.5 : 1
a : b 2.5 : 1 bis 10 : 1 3 : 1 bis 5 : 1
c : b ≥ 1 : 1 ≥ 1 : 1
b : s ≥ 2 : 1
smin ≈ 0.3 mm



Failure Probability of Single and Double (Bifurcated) Contacts (according to Thielecke)

Contact force[N] Single contact
Ag AuNi 5, Pt Ag AuNi 5, Pt
0.04 1 x 10-4 2 x 10-8
0.1 2 x 10-3 4 x 10-5 8 x 10-5 8 x 10-9
0.2 1 x 10-4 8 x 10-6 4 x 10-6 4 x 10-8
0.3 5.5 x 10-6 1.5 x 10-6 1.8 x 10-7 3.2 x 10-10


Figure 2: Failure probability of a contact as a function of the voltage (according to Kirchdorfer); Ag/Ni10; 10 mA
Figure 3: Failure probability of a contact as a function of the current (according to Kirchdorfer); Ag/Ni10; Fk = 0.45 N; U = 24 V

References

References

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