URT
URT
7. Optimal Protection For Rectifier Equipment The criteria for selection of the fuse link providing optimal protection of your rectifier are itemized below. To guarantee trouble free operation all the given points have to be considered. 7.1 Selection Criteria I B I rated The fuse link load current I B has to be smaller than or equal to the fuse link rated current I rated . All influencing components (alternating load, impulse load, thermal influences) have to be considered. U B U rated The operating voltage U B calculated or determined from Figure 5.1 has to be smaller than or equal to the fuse link rated voltage U rated . If in doubt, the rated voltage of the component to be protected can be used as a basis. It has to be considered that during faults and regenerative loads, the voltage to be interrupted at the fuse link may reach 1.8 times the supply voltage. A semi The breaking integral value of the fuse link A has to be smaller than the limited load integral of the semiconductor cell. If necessary, the limited load integral can be calculated by indication of the peak current limit value ITSM of the semiconductor. U L U RRM / DRM The arc or switching voltage U L shall not exceed the value of the positive or negative blocking voltage of the semiconductor cell. I K" It should be checked whether the prospective short circuit current I K" resulting from the reactance of the installation is smaller than the tested maximum breaking capacity of the fuse link. 7.2 Selection Procedure The flow chart gives guidelines on how to select fuse links considering different conditions and influences. 7.3 Protection Analysis or Synthesis Available at SIBA A straightforward solution to designing the appropriate protection for your equipment is offered by the engineering staff in our company. Based on many years of research into semiconductor components, electrical tests and experience in rating fuse links in rectifier circuits, SIBA is in the position to elaborate maximum possible safety. Supported by a fuse calculating program, our engineers will consider your given maximum conditions and accordingly recommend the proper ratings and types for suitable protection. 7.4 Special Designs There may be applications that do not allow the use of standardized fuse links or fuse links of sizes offered in the catalogs. Our possibilities to meet your specifications include, for example, the specific design of contacts; decrease or increase of rated current offered in the data sheets, or specific characteristic of time-current behavior of a fuse link different from our sheets. Any variation is of, course, only practicable within physical limits. In any case, our engineers are prepared from our data to discuss and analyze your technical problems.
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