Page 136 - contactors_motor_protection_for_rolling_stock_application

AF09(Z)B ... AF370B 4-pole contactors

Electrical durability and utilization categories

General
Utilization categories determine the current making and breaking conditions relating to the characteristics of the loads to be
controlled by the contactors. International standard IEC 60947-4-1 and European standard EN 60947-4-1 are the standards
2 to be referred to. If Ic is the current to be broken by the contactor and Ie the rated operational current normally drawn by the
load, then Ic = Ie for category AC-1. The curve corresponding to category AC-1 represents the electrical durability variation of
standard contactors in relation to the breaking current Ic.
Electrical durability is expressed in millions of operating cycles.

Curve utilization mode
Electrical durability forecast and contactor selection for category AC-1
• Note the characteristics of the load to be controlled:
– Operational voltage ........................................................................... Ue
– Current normally drawn ..................................................................... Ie
– Utilization category ........................................................................... AC-1
– Breaking current ............................................................................... Ic = Ie for AC-1
• Define the number of operating cycles N required.
• On the diagram corresponding to the operational category, select the contactor with the curve immediately above the
intersection point (Ic ; N).

Case of uninterrupted duty
For uninterrupted duty, some verifications of preventing maintenance are necessary to check the functionality of the concerned
product (consult us). The combinated effect of environmental conditions and the proper temperature of the product may require
some disposals. As a matter of fact, for this duty, the use duration prevails over the number of operating cycles.

1SBC101843S0201 - Rev. A

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