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→13.4.2.1 Electrical Life
The electrical life of contactors, motor switches, and auxiliary current switches used in power engineering is classified into use categories which are shown in <xr id="tab:Important Use Categories and Their Typical Applications for Contactors and Power Switches"/> (Tab. 13.1).
The making and breaking currents for tests IEC/EN 60947-4-1 are shown in Table <xr id="tab:Verification of Electrical Life Conditions for Make and Break Tests of Contactors and Motor Starters by Utilization Category"/> (Tab. 13.2 ) for the different use categories.
The electrical life of a motor switch is influenced primarily by arc erosion which is generated during make and break arcs on the contact surface. During AC-3 testing, for which the make current is six time the nominal rated current, the arc erosion is mainly caused by the make arcs, especially if frequent contact bounces > 2 ms occur. Therefore the bounce characteristic of switching devices primarily used for “normal” use in switching on and off electrical motors is of critical importance. If make and break currents are the same, as in the ultilisation categories AC-1 and AC-4, the break erosion dominates the arc erosion so much that make erosion can be neglected.
|0.95
|-
|AC-2
|Alle Werte
|2.5
|1
|0.65
|2.5
|1
|0.65
|-
|AC-3
|Alle Werte
|I<sub>e</sub> < 17<br />I<sub>e</sub> > 17
|6<br />6
|1<br />1
|0.65<br />0.35
|1<br />1
|0.17<br />0.17
|0.65<br />0.35
|}
</figtable>
