USEFUL INFORMATION www.krausnaimer.com USEFUL INFO 245 MAIN CATALOG Definition Definition (References: EN 60947 und EN 60204) Utilization category of switchgear Standard utilization categories define the current making and breaking values for switches/contactors for the purpose to enable the selection for the proper switchgear for a particular application. Utilization Categories are depending on the following: • The type of load to be controlled (squirrel cage or slip ring motor, resistors) • The operating cycle conditions (motor running, stalled or starting, reverse operation, counter-current braking Control switch A device capable of making, carrying and breaking current within an electrical circuit under defined conditions. Disconnector A device capable of carrying current within an electrical circuit and providing OFFload isolation within that circuit in accordance with the specified requirements for safety isolation. Switch disconnector Switch disconnectors in their open position fulfil all of the functional demands of an isolator. Disconnect Functionality Functionality to disconnect an electrical systems completely or electrical sub parts of a system form the electrical power source for safety reasons. Main Switch (Power Disconnect) A main switch can be designed as a load break switch or disconnect switch. The load break switch has to fulfill all requirements of utilization category AC23B or higher. The selection of the disconnect switch happens according to the Thermal current. In addition the disconnect switch has to have an auxiliary contact to enable the load break via a contactor. The auxiliary contact has to have a sufficient AC-15 switching capacity. When using a load break switch as main switch the Breaking capacity has to be considered. The Breaking capacity has to match the current of the biggest motor in a system with blocked breaks additionally the sum of all nominal currents of all other electricity consumers in the machine or system. In addition to that the sum of the rated currents of all electricity consumers must not exceed the tolerable limit of the Thermal current of the switch. For main switches with emergency stop functionality the same selection criteria apply. Direct opening action Contact opening action which ensures that all contacts are in an open stage, when the switch handle is in „OFF“ position, according defined conditions. Positively driven operation Switching action which ensures that the Auxiliary contacts of a mechanical switch are matching the switch status of the main contacts („OPEN“ or „CLOSED“) indicated by the handle position („ON“ or „OFF“). Control switch (auxiliary circuit switch) Switch types intended for use as control switch for isolation with direct opening action according to Annex K of IEC 60947-5-1:2016, EN 60947-5-1:2017 and VDW 0660 Part 200:03:2018 referring to Low-Voltage Switchgear and Controlgear, Control Circuit Devices and Switching Elements. < Zurück zum Katalogverzeichnis >
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