Page 39 - Application Guide Semiconductor Fuse Link
P. 39

Selection-A-Fuse for Power Electronics



        Selection of the proper semiconductor fuse for the protection of power electronics circuits can be a
        time-consuming process. The fuse must have adequate a.c. and d.c. voltage ratings, carry the r.m.s.
        continuous current, withstand cyclic and surge overloads and clear short-circuit faults, while limiting
             2
        the I t and peak voltage values. The examples in the previous section showed that in practical
        applications the conditions are not the same as those which were used to determine the published
        fuse performance data. A lengthy set of calculations is required to adjust the standard data to apply
        to real world conditions. Often the initial choice of fuse turns out to be unsuitable, and then the
        calculations have to be repeated for an alternative product.


        Select-A-Fuse for Power Electronics software makes it simple. Just enter the application data, click
        on Search, and the program will give you a list of suitable fuses and their catalog numbers. Fuses are
        selected using the rules and procedures described in this guide.



                                                                                                        2
        The program also contains extensive reference data for Ferraz Shawmut products, such as ratings, I t
        values, time-current and peak let-through curves, and outline drawings.


        The data and results of your selections can be saved to a text fi le for subsequent printing. All graphics
        screens can be printed directly or copied to the Windows clipboard for pasting into your word-
        processor.


        Data is supplied with SAF/PE for the following semiconductor fuse product families:



              • North American (AMPTRAP) round-body fuses with rated a.c. voltages up to 1500V


              •  IEC standard (PROTISTOR) square and rectangular ceramic body fuses, up to 1250V a.c.



        The program is intended for routine applications and contains only part of Ferraz Shawmut’s large
        range of semiconductor fuse products. If you can’t fi nd what you need in SAF/PE, contact Ferraz
        Shawmut Technical Services.


        SAF/PE contains thirteen different power conversion circuits as follows:


































                                                                                                                   39
   34   35   36   37   38   39   40   41   42   43   44