Danfoss VLT 2800 Quick Manual

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4.13 FusesBranch circuit protectionTo protect the installation against electrical and fire hazard,all branch circuits in an installation, switch gear, machinesetc., must be short-circuited and overcurrent protectedaccording to national/international regulations.Short circuit protectionDanfoss recommends using the fuses mentioned inTable 4.7 to protect service personnel and equipment incase of an internal failure in the unit or short-circuit onDC-link. The frequency converter provides full short-circuitprotection in case of a short circuit on the motor or brakeoutput.Overcurrent protectionProvide overload protection to avoid overheating of thecables in the installation. Overcurrent protection mustalways be carried out according to national regulations.Fuses must be designed for protection in a circuit capableof supplying a maximum of 100,000 Arms (symmetrical),480 V maximum.NonIf UL/cUL is not to be complied with, Danfoss recommendsusing the fuses mentioned in Table 4.7, which ensurescompliance with EN50178/IEC61800-5-1.In case of malfunction, not following the fuse recommen-dation may result in damage to the frequency converter.Alternative fuses 380-500 V drivesVLT 2800 BussmannE52273BussmannE4273BussmannE4273BussmannE4273BussmannE4273BussmannE4273SIBAE180276Little FuseE81895Ferraz-ShawmutE163267/E2137Ferraz-ShawmutE163267/E2137RK1/JDDZ J/JDDZ T/JDDZ CC/JDDZ CC/JDDZ CC/JDDZ RK1/JDDZ RK1/JDDZ CC/JDDZ RK1/JDDZ2805-2820 KTS-R20 JKS-20 JJS-20 FNQ-R-20 KTK-R-20 LP-CC-20 5017906-020KLS-R20 ATM-R25 A6K-20R2855-2875 KTS-R25 JKS-25 JJS-25 5017906-025KLS-R25 ATM-R20 A6K-25R2880-2882 KTS-R50 JKS-50 JJS-50 5014006-050KLS-R50 - A6K-50RAlternative Fuses 200-240 V drives2803-2822 KTN-R20 JKS-20 JJN-20 5017906-020KLS-R20 ATM-R25 A6K-20R2840 KTN-R25 JKS-25 JJN-25 5017906-025KLS-R25 ATM-R20 A6K-25RTable 4.7 Prefuses for UL/cUL4.14 RFI Switch (VLT 2880-2882 Only)Mains supply isolated from earthIf the frequency converter is supplied from an isolatedmains source ( IT mains) or TT/TN-S mains with groundedleg, the RFI switch is recommended to be turned off (OFF).For further reference, see IEC 364-3. If optimum EMCperformance is needed, parallel motors are connected orthe motor cable length is above 25 m, set the switch inON position.In OFF position, the internal RFI capacities (filter capacitors)between the chassis and the intermediate circuit are cutoff to avoid damage to the intermediate circuit and toreduce the ground capacity currents (according to IEC61800-3).Also refer to the application note VLT on IT mains. It isimportant to use isolation monitors that are capable foruse together with power electronics (IEC 61557-8).NOTICEThe RFI switch is not to be operated with mainsconnected to the unit. Check that the mains supply hasbeen disconnected before operating the RFI switch.The RFI switch disconnects the capacitors galvanicallyfrom ground.Remove the switch Mk9, placed next to terminal 96, todisconnect the RFI-filter.Electrical Installation Quick GuideMG28M202 Danfoss A/S © Rev. 2014-03-18 All rights reserved. 174 4